Clare - are smaller car tires easier to balance than SUV tires?
https://i.postimg.cc/kG1M7cLd/mount15.jpg

A neighbor was in need of tires who knew that I had bought a few extra for
her long ago where they've been sitting outside in the rain & mud for
months waiting for her to need them.
https://i.postimg.cc/7L8HPbtb/mount16.jpg

She finally wore through the belts and had to stop over for an "emergency"
tire change, which I did for her, but she was in a rush so we did it in
about 20 minutes from start to finish.

I had to do it so fast that I didn't see the yellow dot until I looked at
this picture, where I mounted the red dot to the valve stem instead of the
yellow dot as you had recommended for when there are no match mounting
marks.

I did statically balance and she reported no vibration whatsoever. I didn't
spend a lot of time cleaning up things so I'm surprised there's no
imbalance given how quickly I did the job for her.

Just wondering if you've found that these tiny 14-inch tires are a piece of
cake compared to the normal truck SUV tires (like the Optimo's that I'm
used to) both in terms of mounting and balancing?

On 6/12/19 1:52 AM, Arlen G. Holder wrote:
she was in a rush so we did it in
about 20 minutes from start to finish.

Now that's a quickie!

On 6/12/2019 6:24 AM, devnull wrote:
On 6/12/19 1:52 AM, Arlen G. Holder wrote:
she was in a rush so we did it in
about 20 minutes from start to finish.

Now that's a quickie!


Yeah, but it was 19 minutes foreplay.

On 6/12/19 4:17 PM, Ed Pawlowski wrote:
On 6/12/2019 6:24 AM, devnull wrote:
On 6/12/19 1:52 AM, Arlen G. Holder wrote:
she was in a rush so we did it in
about 20 minutes from start to finish.

Now that's a quickie!


Yeah, but it was 19 minutes foreplay.


If the nuts are rusty, sometimes you got to heat up the stud to get them off.

On 6/12/2019 4:43 PM, devnull wrote:
On 6/12/19 4:17 PM, Ed Pawlowski wrote:
On 6/12/2019 6:24 AM, devnull wrote:
On 6/12/19 1:52 AM, Arlen G. Holder wrote:
she was in a rush so we did it in
about 20 minutes from start to finish.

Now that's a quickie!


Yeah, but it was 19 minutes foreplay.


If the nuts are rusty, sometimes you got to heat up the stud to get them
off.


Better than having them bleed
https://nypost.com/2019/06/11/florid...hey-bled-cops/

On Wed, 12 Jun 2019 05:52:33 -0000 (UTC), "Arlen G. Holder"
wrote:

Clare - are smaller car tires easier to balance than SUV tires?
https://i.postimg.cc/kG1M7cLd/mount15.jpg

A neighbor was in need of tires who knew that I had bought a few extra for
her long ago where they've been sitting outside in the rain & mud for
months waiting for her to need them.
https://i.postimg.cc/7L8HPbtb/mount16.jpg

She finally wore through the belts and had to stop over for an "emergency"
tire change, which I did for her, but she was in a rush so we did it in
about 20 minutes from start to finish.

I had to do it so fast that I didn't see the yellow dot until I looked at
this picture, where I mounted the red dot to the valve stem instead of the
yellow dot as you had recommended for when there are no match mounting
marks.

I did statically balance and she reported no vibration whatsoever. I didn't
spend a lot of time cleaning up things so I'm surprised there's no
imbalance given how quickly I did the job for her.

Just wondering if you've found that these tiny 14-inch tires are a piece of
cake compared to the normal truck SUV tires (like the Optimo's that I'm
used to) both in terms of mounting and balancing?


Yes and no. The smaller tire has less total mass so a small amount
of weight has more effect than it would on a bigger tire - but it is
not as far from the center (shorter moment arm) so it has less effect.

GOOD tires of any size are easier to ballance than crappy tires. Ealy
Hankooks were a real pain to ballance. Apparentlythey have gotten
better.

On Wed, 12 Jun 2019 21:37:49 -0400, Clare Snyder wrote:

Yes and no. The smaller tire has less total mass so a small amount
of weight has more effect than it would on a bigger tire - but it is
not as far from the center (shorter moment arm) so it has less effect.

Thanks Clare as I never mounted and balanced a tire so fast on purpose, not
even taking time to clean the wheel or even remove the old weights until
AFTER I put it on the static balance stand.

These tires are Lexani LXTR 203 model tires, of size P185/65R14 with load
range 86 and speed range H (traction A, temperature A, and treadwear 500),
where I don't know WHAT specific thing makes these so easy to balance, but
they're so easy that something is very different.

I was surprised that I skipped a bunch of steps, and yet, the wheel _still_
didn't cause any perceptible vibration, according to the driver, even as
it's a front wheel drive vehicle with the tire being the driver side front
tire.

I had told the owner to take it to Costco for the $5 wheel balancing, but
that wasn't even necessary, even as I skipped a bunch of balancing steps.

The old tires on her car were model "Grand Prix" of size P185/65R14 load
range 86 and speed of T (traction A, temperature B, and treadwear 500)
which seem to be wearing on both edges, where here are the front two tires
of this FWD vehicle with the tires set up in the appropriate position.
https://i.postimg.cc/JzvTyjKg/mount18.jpg

I had previously replaced her passenger front tire due to this gouge
https://i.postimg.cc/4dTBPZDQ/mount19.jpg

Where the driver front tire wore into the steel belts which jutted out
https://i.postimg.cc/85Bwn9DQ/mount20.jpg

She needed to be somewhere so I was in such a rush, that I didn't even
_see_ the yellow (weight) dot when I mounted the valve stem to the red
(uniformity) dot:
https://i.postimg.cc/7L8HPbtb/mount16.jpg

Where I only noticed the yellow dot when I looked at this picture!
https://i.postimg.cc/kG1M7cLd/mount15.jpg

Back to how easy it was to statically balance these tires, not only did
this tiny car have the only four-lug wheel I've ever worked on, but popping
the first bead of this tiny 14-inch P185 tire was so simple that it took
only a couple of pumps and about triple that to break the second bead.

Removing the third bead and fourth bead was, likewise, surprisingly simple.
Popping on the fifth bead was almost entirely done by hand, it was that
easy, where only the sixth bead took any effort whatsoever that required a
force that any teenager could exert.

With two wheel weights already on the rim, and by match mounting the red
dot (I didn't even _see_ that yellow dot until I looked at the picture
afterward), the balance was spot on in the middle of the bubble level.

So I didn't even remove the _old_ wheel weights, which I normally would
have done as part of the wheel prep after breaking the bead and removing
the old tire. I didn't even replace the valve stem, as I recently used up
the four valve stems I had bought after speaking to you about getting the
bolt-in kind so I didn't have any available.

The tires have been waiting for her outside in the mud and rain, so I
simply bounced and blew out the leaves and crud where I would have cleaned
the tires more had I more time, where I might have noticed that yellow dot
which was slightly worn away from being outside all winter.

GOOD tires of any size are easier to ballance than crappy tires. Ealy
Hankooks were a real pain to ballance. Apparentlythey have gotten
better.

Funny you mention the Hankook's where I just snapped this for you!
https://i.postimg.cc/zGVtXxwK/mount17.jpg

Those are Hancook Optimo H724 model tires of size P225/75R15, with the load
range of 102 and speed range of S (traction A, temperature B, and treadwear
500), which were MUCH HARDER to mount and dismount and harder to balance
too, it seems.

I'm planning on mounting and balancing them this weekend on an SUV which
keeps wearing out the front tires which I have to get alignment tools to
check the camber mostly since they're wearing on the outside edge.

When I mount those thick-sided Hancooks, on steel wheels, I will mount by
the _yellow_ (minimum weight) dot for the first time, instead of by the red
(maximum runout) dot, as I recall you recommended for when there's no match
mounting mark on the rims.

Thanks for being helpful where you're just about the only guy on this
newsgroup who knows anything about this subject matter, which I greatly
appreciate your advice, and where I try to remember it all over the years,
where I'm starting to lose count of how many tires I've done in the past
five years with the crappy Harbor Freight tools (they work, but they suck).

On 13/6/19 2:32 pm, Arlen G. Holder wrote:
On Wed, 12 Jun 2019 21:37:49 -0400, Clare Snyder wrote:

Yes and no. The smaller tire has less total mass so a small amount
of weight has more effect than it would on a bigger tire - but it is
not as far from the center (shorter moment arm) so it has less effect.

Thanks Clare as I never mounted and balanced a tire so fast on purpose, not
even taking time to clean the wheel or even remove the old weights until
AFTER I put it on the static balance stand.

These tires are Lexani LXTR 203 model tires, of size P185/65R14 with load
range 86 and speed range H (traction A, temperature A, and treadwear 500),
where I don't know WHAT specific thing makes these so easy to balance, but
they're so easy that something is very different.

I was surprised that I skipped a bunch of steps, and yet, the wheel _still_
didn't cause any perceptible vibration, according to the driver, even as
it's a front wheel drive vehicle with the tire being the driver side front
tire.

I had told the owner to take it to Costco for the $5 wheel balancing, but
that wasn't even necessary, even as I skipped a bunch of balancing steps.

The old tires on her car were model "Grand Prix" of size P185/65R14 load
range 86 and speed of T (traction A, temperature B, and treadwear 500)
which seem to be wearing on both edges, where here are the front two tires
of this FWD vehicle with the tires set up in the appropriate position.
https://i.postimg.cc/JzvTyjKg/mount18.jpg

I had previously replaced her passenger front tire due to this gouge
https://i.postimg.cc/4dTBPZDQ/mount19.jpg

Where the driver front tire wore into the steel belts which jutted out
https://i.postimg.cc/85Bwn9DQ/mount20.jpg

She needed to be somewhere so I was in such a rush, that I didn't even
_see_ the yellow (weight) dot when I mounted the valve stem to the red
(uniformity) dot:
https://i.postimg.cc/7L8HPbtb/mount16.jpg

Where I only noticed the yellow dot when I looked at this picture!
https://i.postimg.cc/kG1M7cLd/mount15.jpg

Back to how easy it was to statically balance these tires, not only did
this tiny car have the only four-lug wheel I've ever worked on, but popping
the first bead of this tiny 14-inch P185 tire was so simple that it took
only a couple of pumps and about triple that to break the second bead.

Removing the third bead and fourth bead was, likewise, surprisingly simple.
Popping on the fifth bead was almost entirely done by hand, it was that
easy, where only the sixth bead took any effort whatsoever that required a
force that any teenager could exert.

With two wheel weights already on the rim, and by match mounting the red
dot (I didn't even _see_ that yellow dot until I looked at the picture
afterward), the balance was spot on in the middle of the bubble level.

So I didn't even remove the _old_ wheel weights, which I normally would
have done as part of the wheel prep after breaking the bead and removing
the old tire. I didn't even replace the valve stem, as I recently used up
the four valve stems I had bought after speaking to you about getting the
bolt-in kind so I didn't have any available.

The tires have been waiting for her outside in the mud and rain, so I
simply bounced and blew out the leaves and crud where I would have cleaned
the tires more had I more time, where I might have noticed that yellow dot
which was slightly worn away from being outside all winter.

GOOD tires of any size are easier to ballance than crappy tires. Ealy
Hankooks were a real pain to ballance. Apparentlythey have gotten
better.

Funny you mention the Hankook's where I just snapped this for you!
https://i.postimg.cc/zGVtXxwK/mount17.jpg

Those are Hancook Optimo H724 model tires of size P225/75R15, with the load
range of 102 and speed range of S (traction A, temperature B, and treadwear
500), which were MUCH HARDER to mount and dismount and harder to balance
too, it seems.

I'm planning on mounting and balancing them this weekend on an SUV which
keeps wearing out the front tires which I have to get alignment tools to
check the camber mostly since they're wearing on the outside edge.

You can check the camber all you like but the answer is more likely in
the SAI angles and you will be able to do SFA about that. Quiz the owner
about type of use instead. If it is all city and suburban driving, tyre
wear on the outside of the tread can be considered 100% normal.
Turn the wheels to a high level of lock and the obvious will confront
you. The type of feathering will tell you what the actual cause is.

When I mount those thick-sided Hancooks, on steel wheels, I will mount by
the _yellow_ (minimum weight) dot for the first time, instead of by the red
(maximum runout) dot, as I recall you recommended for when there's no match
mounting mark on the rims.

Thanks for being helpful where you're just about the only guy on this
newsgroup who knows anything about this subject matter, which I greatly
appreciate your advice, and where I try to remember it all over the years,
where I'm starting to lose count of how many tires I've done in the past
five years with the crappy Harbor Freight tools (they work, but they suck).



--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

On Thu, 13 Jun 2019 04:32:45 -0000 (UTC), "Arlen G. Holder"
wrote:

On Wed, 12 Jun 2019 21:37:49 -0400, Clare Snyder wrote:

Yes and no. The smaller tire has less total mass so a small amount
of weight has more effect than it would on a bigger tire - but it is
not as far from the center (shorter moment arm) so it has less effect.

Thanks Clare as I never mounted and balanced a tire so fast on purpose, not
even taking time to clean the wheel or even remove the old weights until
AFTER I put it on the static balance stand.

These tires are Lexani LXTR 203 model tires, of size P185/65R14 with load
range 86 and speed range H (traction A, temperature A, and treadwear 500),
where I don't know WHAT specific thing makes these so easy to balance, but
they're so easy that something is very different.

I was surprised that I skipped a bunch of steps, and yet, the wheel _still_
didn't cause any perceptible vibration, according to the driver, even as
it's a front wheel drive vehicle with the tire being the driver side front
tire.

I had told the owner to take it to Costco for the $5 wheel balancing, but
that wasn't even necessary, even as I skipped a bunch of balancing steps.

The old tires on her car were model "Grand Prix" of size P185/65R14 load
range 86 and speed of T (traction A, temperature B, and treadwear 500)
which seem to be wearing on both edges, where here are the front two tires
of this FWD vehicle with the tires set up in the appropriate position.
https://i.postimg.cc/JzvTyjKg/mount18.jpg

I had previously replaced her passenger front tire due to this gouge
https://i.postimg.cc/4dTBPZDQ/mount19.jpg

Running the dang things half flat or cornering like an idiot - - -

Where the driver front tire wore into the steel belts which jutted out
https://i.postimg.cc/85Bwn9DQ/mount20.jpg

Driving on tires like that should be criminal

She needed to be somewhere so I was in such a rush, that I didn't even
_see_ the yellow (weight) dot when I mounted the valve stem to the red
(uniformity) dot:
https://i.postimg.cc/7L8HPbtb/mount16.jpg

Where I only noticed the yellow dot when I looked at this picture!
https://i.postimg.cc/kG1M7cLd/mount15.jpg

Back to how easy it was to statically balance these tires, not only did
this tiny car have the only four-lug wheel I've ever worked on, but popping
the first bead of this tiny 14-inch P185 tire was so simple that it took
only a couple of pumps and about triple that to break the second bead.

Removing the third bead and fourth bead was, likewise, surprisingly simple.
Popping on the fifth bead was almost entirely done by hand, it was that
easy, where only the sixth bead took any effort whatsoever that required a
force that any teenager could exert.

With two wheel weights already on the rim, and by match mounting the red
dot (I didn't even _see_ that yellow dot until I looked at the picture
afterward), the balance was spot on in the middle of the bubble level.

So I didn't even remove the _old_ wheel weights, which I normally would
have done as part of the wheel prep after breaking the bead and removing
the old tire. I didn't even replace the valve stem, as I recently used up
the four valve stems I had bought after speaking to you about getting the
bolt-in kind so I didn't have any available.

The tires have been waiting for her outside in the mud and rain, so I
simply bounced and blew out the leaves and crud where I would have cleaned
the tires more had I more time, where I might have noticed that yellow dot
which was slightly worn away from being outside all winter.

GOOD tires of any size are easier to ballance than crappy tires. Ealy
Hankooks were a real pain to ballance. Apparentlythey have gotten
better.

Funny you mention the Hankook's where I just snapped this for you!
https://i.postimg.cc/zGVtXxwK/mount17.jpg

Those are Hancook Optimo H724 model tires of size P225/75R15, with the load
range of 102 and speed range of S (traction A, temperature B, and treadwear
500), which were MUCH HARDER to mount and dismount and harder to balance
too, it seems.

I'm planning on mounting and balancing them this weekend on an SUV which
keeps wearing out the front tires which I have to get alignment tools to
check the camber mostly since they're wearing on the outside edge.

When I mount those thick-sided Hancooks, on steel wheels, I will mount by
the _yellow_ (minimum weight) dot for the first time, instead of by the red
(maximum runout) dot, as I recall you recommended for when there's no match
mounting mark on the rims.

Thanks for being helpful where you're just about the only guy on this
newsgroup who knows anything about this subject matter, which I greatly
appreciate your advice, and where I try to remember it all over the years,
where I'm starting to lose count of how many tires I've done in the past
five years with the crappy Harbor Freight tools (they work, but they suck).

On Thu, 13 Jun 2019 11:45:55 -0400, Clare Snyder wrote:

Running the dang things half flat or cornering like an idiot

Hi Clare,

Thanks for that advice, as I am "trying" to "read" the story of tires, but
I'm not doing well as most of it is cryptic to me, while it might be
obvious to you - so I appreciate any insight you can give on how you read
tire wear.

I agree with you that it's unusual for a gouge that big that the treads
were visible underneath, as shown below...
https://i.postimg.cc/hjgtsc3Z/mount21.jpg
and where the tire finally just deflated in split second while she was
pulling out of her driveway.
https://i.postimg.cc/4dTBPZDQ/mount19.jpg

Driving on tires like that should be criminal

I have two more tires to put on for her for her rears, which are worn more
evenly (she probably doesn't rotate?) so I told her to wait until she
needed them since they are just sitting outside (I moved them into the
garage as they were getting dirty in the rain over the winter).

I have never owned a FWD vehicle so I'm not sure yet how the wear patterns
differ, but this set of tires seems to be worn on both outside edges with
the actual edge being hit the hardest.
https://i.postimg.cc/RCRdRMWd/mount22.jpg

On Thu, 13 Jun 2019 17:11:14 +1000, Xeno wrote:

You can check the camber all you like but the answer is more likely in
the SAI angles and you will be able to do SFA about that.

Hi Xeno,

Thanks for your purposefully helpful advice on kingpin inclination angle
(aka steering axis inclination), and perhaps included angle, neither of
which have I delved into yet (as I'm starting with camber, which is the
basis for caster calculations, and where toe is relatively simple).
http://www.valleyofhastings.com/WheelAlignment2.pdf

Other than Clare, you and maybe one or two other folks here are
knowledgeable in the important details of home alignment checks &
adjustments, where I don't usually disagree with anything you guys say, as
you know more than I do.

We have to remember a home DIY alignment check & adjust is sort of like
doing a DIY tuneup versus a complete engine overhaul
o A DIY caster/camber/toe check/adjust is to a professional alignment
o as a DIY tuneup is to a professional engine blueprinting overhaul

The fact is that the SIA is a "non adujstable" angle:
https://www.freeasestudyguides.com/included-angle.html

The fact it's not adjustable means it is in a different category than
o caster
o camber
o toe

While SIA is not normally adjustable, looking this up anyway for more
insight, it seems SIA checks generally simply need yet _another_ magnetic
bubble gauge, much like the camber gauge apparently, but offset by 90
degrees, according to this cite:
o Checking the Steering Axis Inclination Angle
http://route66hotrodhigh.com/Inclination.html
Which says:
"To measure steering axis inclination, the method is identical to caster
measurement except that you use the steering axis inclination guage [sic]
which is at a 90 deg angle to the caster gauge. The wheel is turned 20 deg
inward. The steering axis inclination gauge is centered for 0 deg caster.
There is an adjustment screw on the back of the gauge that allows you to
set it for 0 deg. The wheel is then turned to 20 deg outward for a total
movement of 40 degrees. The steering axis inclination angle is read off the
gauge."

The key question is where to get that SIA gauge, which, apparently, can be
replaced with a normal magnetic caster gauge according to this patent:
o Device & method for measuring SAI on a steerable wheel (#4,546,548)
http://www.freepatentsonline.com/4546548.pdf

In short, if we're aligning a vehicle that we own and drive often, then we
don't have any reason to suspect SIA changes (which will only occur with
bent or worn parts), and hence, they aren't part of what typically changes
(which is caster, camber, and toe).
https://www.motor.com/magazinepdfs/062002_05.pdf

about type of use instead. If it is all city and suburban driving, tyre
wear on the outside of the tread can be considered 100% normal.

On this mountain, everyone wears tires sooner than people who drive in
flatland do, where there is just "something" horrific about five miles of
steep driving,

Most seem to wear on the outside edge, which I still haven't figured out
exactly why. The road is about 5 miles at about a 9 percent angle with very
many 180 degree and even 270 degree switchbacks, but the speeds are rather
slow, where the road is too narrow to even have panted centerlines and
where the nominal speed limit for such roads is 25mph.

Given nobody drives 25 mph anywhere, we can figure it's something like 30
mph to 40 mph top speed but there's a lot of braking in between. Me? I just
put the tranny in neutral and roll down the entire five miles by giving up
potential energy, where I only brake when I must and I take the turns very
wide (as most people do) which helps maintain speed.

Somehow, _that_ process (which most people do, I think, but in gear most
likely), wears tires out like you can't believe, where tires get half the
stated mileage, as far as I can tell by aggregate conversations.

Turn the wheels to a high level of lock and the obvious will confront
you. The type of feathering will tell you what the actual cause is.

I do admit that I can't 'read' a tire very well. I've tried, but rotations
screw up the readings, and certainly there can be multiple causes.

The type of feathering I mostly see is the kind you can feel after only
about 1000 miles on the outside edge, for about 3 inches of tread, where
there is a sharp lip that is feathered into that outside tread that you can
only feel moving your hand clockwise over the front tire tread on the
outside 3 inches.

I need to learn more, but I think that's "normal" since it happens even
after I get a professional alignment. I'm due for one soon for a couple of
cars, which is why, instead of paying the $150 per vehicle, which for the 3
cars I want to do first, will be almost five hundred bucks, I'd rather buy
the tools to do it myself for that same five hundred bucks.
o Caster gauge (to measure caster & calculate camber)
o Caster jig (to lock onto the wheel for the caster gauge to be accurate)
o Wheel plates (to move the wheels for adjustment under suspension loading)
o Toe plates (to enable single-person linear measurement to centerline)

After having discussed this with Clare in the past, I know we can redneck
some of that, but overall, those four items seem to be the key items needed
for a home DIY check/change of caster, camber, & toe, do you agree?

On Thu, 13 Jun 2019 20:28:06 -0000 (UTC), "Arlen G. Holder"
wrote:

On Thu, 13 Jun 2019 11:45:55 -0400, Clare Snyder wrote:

Running the dang things half flat or cornering like an idiot

Hi Clare,

Thanks for that advice, as I am "trying" to "read" the story of tires, but
I'm not doing well as most of it is cryptic to me, while it might be
obvious to you - so I appreciate any insight you can give on how you read
tire wear.

I agree with you that it's unusual for a gouge that big that the treads
were visible underneath, as shown below...
https://i.postimg.cc/hjgtsc3Z/mount21.jpg
and where the tire finally just deflated in split second while she was
pulling out of her driveway.
https://i.postimg.cc/4dTBPZDQ/mount19.jpg

Driving on tires like that should be criminal

I have two more tires to put on for her for her rears, which are worn more
evenly (she probably doesn't rotate?) so I told her to wait until she
needed them since they are just sitting outside (I moved them into the
garage as they were getting dirty in the rain over the winter).

I have never owned a FWD vehicle so I'm not sure yet how the wear patterns
differ, but this set of tires seems to be worn on both outside edges with
the actual edge being hit the hardest.
https://i.postimg.cc/RCRdRMWd/mount22.jpg
I always try to run my front tires aver placard pressure by a few
pounds - ESPECIALLY on front wheel drive vehicles that will be
cornered hard (basically anything I drive except for the baby Fiat I'm
currently (babysitting) driving - which is a rear engine rear drive
swing axle car with bad rear shocks - - -

On Thu, 13 Jun 2019 20:28:17 -0000 (UTC), "Arlen G. Holder"
wrote:

On Thu, 13 Jun 2019 17:11:14 +1000, Xeno wrote:

You can check the camber all you like but the answer is more likely in
the SAI angles and you will be able to do SFA about that.

Hi Xeno,

Thanks for your purposefully helpful advice on kingpin inclination angle
(aka steering axis inclination), and perhaps included angle, neither of
which have I delved into yet (as I'm starting with camber, which is the
basis for caster calculations, and where toe is relatively simple).
http://www.valleyofhastings.com/WheelAlignment2.pdf

Other than Clare, you and maybe one or two other folks here are
knowledgeable in the important details of home alignment checks &
adjustments, where I don't usually disagree with anything you guys say, as
you know more than I do.

We have to remember a home DIY alignment check & adjust is sort of like
doing a DIY tuneup versus a complete engine overhaul
o A DIY caster/camber/toe check/adjust is to a professional alignment
o as a DIY tuneup is to a professional engine blueprinting overhaul

The fact is that the SIA is a "non adujstable" angle:
https://www.freeasestudyguides.com/included-angle.html

The fact it's not adjustable means it is in a different category than
o caster
o camber
o toe

While SIA is not normally adjustable, looking this up anyway for more
insight, it seems SIA checks generally simply need yet _another_ magnetic
bubble gauge, much like the camber gauge apparently, but offset by 90
degrees, according to this cite:
o Checking the Steering Axis Inclination Angle
http://route66hotrodhigh.com/Inclination.html
Which says:
"To measure steering axis inclination, the method is identical to caster
measurement except that you use the steering axis inclination guage [sic]
which is at a 90 deg angle to the caster gauge. The wheel is turned 20 deg
inward. The steering axis inclination gauge is centered for 0 deg caster.
There is an adjustment screw on the back of the gauge that allows you to
set it for 0 deg. The wheel is then turned to 20 deg outward for a total
movement of 40 degrees. The steering axis inclination angle is read off the
gauge."

The key question is where to get that SIA gauge, which, apparently, can be
replaced with a normal magnetic caster gauge according to this patent:
o Device & method for measuring SAI on a steerable wheel (#4,546,548)
http://www.freepatentsonline.com/4546548.pdf

In short, if we're aligning a vehicle that we own and drive often, then we
don't have any reason to suspect SIA changes (which will only occur with
bent or worn parts), and hence, they aren't part of what typically changes
(which is caster, camber, and toe).
https://www.motor.com/magazinepdfs/062002_05.pdf

about type of use instead. If it is all city and suburban driving, tyre
wear on the outside of the tread can be considered 100% normal.

On this mountain, everyone wears tires sooner than people who drive in
flatland do, where there is just "something" horrific about five miles of
steep driving,

I'd be cranking in a couple degrees of negative camber for extensive
downhill twisties. And running about 36PSI minimum pressure in the
front tires.

Most seem to wear on the outside edge, which I still haven't figured out
exactly why. The road is about 5 miles at about a 9 percent angle with very
many 180 degree and even 270 degree switchbacks, but the speeds are rather
slow, where the road is too narrow to even have panted centerlines and
where the nominal speed limit for such roads is 25mph.

Given nobody drives 25 mph anywhere, we can figure it's something like 30
mph to 40 mph top speed but there's a lot of braking in between. Me? I just
put the tranny in neutral and roll down the entire five miles by giving up
potential energy, where I only brake when I must and I take the turns very
wide (as most people do) which helps maintain speed.

Somehow, _that_ process (which most people do, I think, but in gear most
likely), wears tires out like you can't believe, where tires get half the
stated mileage, as far as I can tell by aggregate conversations.

Turn the wheels to a high level of lock and the obvious will confront
you. The type of feathering will tell you what the actual cause is.

I do admit that I can't 'read' a tire very well. I've tried, but rotations
screw up the readings, and certainly there can be multiple causes.

The type of feathering I mostly see is the kind you can feel after only
about 1000 miles on the outside edge, for about 3 inches of tread, where
there is a sharp lip that is feathered into that outside tread that you can
only feel moving your hand clockwise over the front tire tread on the
outside 3 inches.

I need to learn more, but I think that's "normal" since it happens even
after I get a professional alignment. I'm due for one soon for a couple of
cars, which is why, instead of paying the $150 per vehicle, which for the 3
cars I want to do first, will be almost five hundred bucks, I'd rather buy
the tools to do it myself for that same five hundred bucks.
o Caster gauge (to measure caster & calculate camber)

You got that backwards - - - - You MEASURE camber and calculate
caster (unless you have PROPER equipment which measures both)
o Caster jig (to lock onto the wheel for the caster gauge to be accurate)
o Wheel plates (to move the wheels for adjustment under suspension loading)
o Toe plates (to enable single-person linear measurement to centerline)

After having discussed this with Clare in the past, I know we can redneck
some of that, but overall, those four items seem to be the key items needed
for a home DIY check/change of caster, camber, & toe, do you agree?


It might take a REAL PRO to modify the camber properly likely require
installation of either camber plates or long lower control arms (or
offset bushings)

On 14/6/19 6:28 am, Arlen G. Holder wrote:
On Thu, 13 Jun 2019 17:11:14 +1000, Xeno wrote:

You can check the camber all you like but the answer is more likely in
the SAI angles and you will be able to do SFA about that.

Hi Xeno,

Thanks for your purposefully helpful advice on kingpin inclination angle
(aka steering axis inclination), and perhaps included angle, neither of
which have I delved into yet (as I'm starting with camber, which is the
basis for caster calculations, and where toe is relatively simple).
http://www.valleyofhastings.com/WheelAlignment2.pdf

Use the term Steering Axis Inclination (SAI) as your vehicle likely does
not have kingpins. They are only found on trucks these days. I am of the
old school so I still use KPI but I found, when teaching apprentices,
the term is meaningless to them because most have never seen kingpins
much less worked on a vehicle so equipped.

Other than Clare, you and maybe one or two other folks here are
knowledgeable in the important details of home alignment checks &
adjustments, where I don't usually disagree with anything you guys say, as
you know more than I do.

We have to remember a home DIY alignment check & adjust is sort of like
doing a DIY tuneup versus a complete engine overhaul
o A DIY caster/camber/toe check/adjust is to a professional alignment
o as a DIY tuneup is to a professional engine blueprinting overhaul

The fact is that the SIA is a "non adujstable" angle:
https://www.freeasestudyguides.com/included-angle.html

The fact it's not adjustable means it is in a different category than
o caster
o camber
o toe

SAI, to the serviceman, is a *diagnosis angle* in much the same way as
*toe out on turns* (TOOT) is a diagnosis angle. If your toe is correct
but TOOT is incorrect, you can be assured that you have something that
is *bent*, usually a steering arm. Note, you cannot *adjust* TOOT in
cars as it is *designed in* as part of the Ackermann Angle.

While SIA is not normally adjustable, looking this up anyway for more
insight, it seems SIA checks generally simply need yet _another_ magnetic
bubble gauge, much like the camber gauge apparently, but offset by 90
degrees, according to this cite:
o Checking the Steering Axis Inclination Angle
http://route66hotrodhigh.com/Inclination.html
Which says:
"To measure steering axis inclination, the method is identical to caster
measurement except that you use the steering axis inclination guage [sic]
which is at a 90 deg angle to the caster gauge. The wheel is turned 20 deg
inward. The steering axis inclination gauge is centered for 0 deg caster.
There is an adjustment screw on the back of the gauge that allows you to
set it for 0 deg. The wheel is then turned to 20 deg outward for a total
movement of 40 degrees. The steering axis inclination angle is read off the
gauge."

The key question is where to get that SIA gauge, which, apparently, can be
replaced with a normal magnetic caster gauge according to this patent:
o Device & method for measuring SAI on a steerable wheel (#4,546,548)
http://www.freepatentsonline.com/4546548.pdf

In short, if we're aligning a vehicle that we own and drive often, then we
don't have any reason to suspect SIA changes (which will only occur with
bent or worn parts), and hence, they aren't part of what typically changes
(which is caster, camber, and toe).
https://www.motor.com/magazinepdfs/062002_05.pdf

about type of use instead. If it is all city and suburban driving, tyre
wear on the outside of the tread can be considered 100% normal.

On this mountain, everyone wears tires sooner than people who drive in
flatland do, where there is just "something" horrific about five miles of
steep driving,

Steep driving, urban driving, same thing really. You are at a greater
lock more often, even at slow speed, than when you are out on the
highways and freeways.

Most seem to wear on the outside edge, which I still haven't figured out
exactly why.

The term is Camber Scrub, and it caused a particular type of feathered
wear (for and aft feather IIRC) on the outside of the tyre, but it isn't
caused by the *camber angle* per se. It is caused by what SAI does to
the camber angles in a turn. Here is a video clip describing *one* of
the reasons for SAI.

https://www.youtube.com/watch?v=IZLiP_37Oso

The narrator focuses on the need to reduce unwanted feedback through the
steering. No mention is made of the other major reasons for SAI and that
is steering self centering and torque steer reduction. There are a
number of factors involved in steering stability and self centering
including; SAI, Caster, Camber, mechanical trail and tyre trail.

In this video clip he mentions the self centering effect at the end. He
states that turning the steering forces the axle (and wheel) down and,
in effect, lifts the front of the car. That provides the self centering
effect as the weight of the car will tend to return the steering to its
central or straight ahead position. That downward force also creates a
change in the *camber angle*.

https://www.youtube.com/watch?v=IUcZ63unEyU

But it is the camber angle the wheel adopts when at the turn position,
caused by SAI, that causes *camber scrub*.

This clip https://www.youtube.com/watch?v=VbReLNi2JP4 provides a very
good description of the steering functions. Skip to 13:50 for a
graphical display of the camber angle change when turning.

The road is about 5 miles at about a 9 percent angle with very
many 180 degree and even 270 degree switchbacks, but the speeds are rather
slow, where the road is too narrow to even have panted centerlines and
where the nominal speed limit for such roads is 25mph.

Definitely camber scrub territory.

Given nobody drives 25 mph anywhere, we can figure it's something like 30
mph to 40 mph top speed but there's a lot of braking in between. Me? I just
put the tranny in neutral and roll down the entire five miles by giving up
potential energy, where I only brake when I must and I take the turns very
wide (as most people do) which helps maintain speed.

Somehow, _that_ process (which most people do, I think, but in gear most
likely), wears tires out like you can't believe, where tires get half the
stated mileage, as far as I can tell by aggregate conversations.

Do the same distance on straight roads and you will have fairly even
tyre wear.

Turn the wheels to a high level of lock and the obvious will confront
you. The type of feathering will tell you what the actual cause is.

I do admit that I can't 'read' a tire very well. I've tried, but rotations
screw up the readings, and certainly there can be multiple causes.

It takes practice and, since I haven't operated a wheel aligner for a
very long time, I am *out of practice* but I've had the priciples
hammered into me over the decades ably assisted by having taught the
principles for some 20 years.

The type of feathering I mostly see is the kind you can feel after only
about 1000 miles on the outside edge, for about 3 inches of tread, where
there is a sharp lip that is feathered into that outside tread that you can
only feel moving your hand clockwise over the front tire tread on the
outside 3 inches.

That sounds like camber scrub feathering - if I'm reading your
description correctly.

I need to learn more, but I think that's "normal" since it happens even
after I get a professional alignment. I'm due for one soon for a couple of

A *professional alignment* cannot fix a *symptom* that is considered
*normal* for the kind of driving you do. Any changes made to mitigate
camber scrub will cause a reduction in handling capability at speed.

cars, which is why, instead of paying the $150 per vehicle, which for the 3
cars I want to do first, will be almost five hundred bucks, I'd rather buy
the tools to do it myself for that same five hundred bucks.
o Caster gauge (to measure caster & calculate camber)
o Caster jig (to lock onto the wheel for the caster gauge to be accurate)
o Wheel plates (to move the wheels for adjustment under suspension loading)
o Toe plates (to enable single-person linear measurement to centerline)

After having discussed this with Clare in the past, I know we can redneck
some of that, but overall, those four items seem to be the key items needed
for a home DIY check/change of caster, camber, & toe, do you agree?

Yes, that is basically all the small service station had next door to
where I did my apprenticeship. You have missed the primary requisite
however - a guaranteed dead flat and level garage floor. Also a lock to
lock the steering wheel to the desired centre position;
https://i.ebayimg.com/images/g/sJIAA...58p/s-l225.jpg



--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

On Thu, 13 Jun 2019 21:17:18 -0400, Clare Snyder wrote:

I'd be cranking in a couple degrees of negative camber for extensive
downhill twisties. And running about 36PSI minimum pressure in the
front tires.

Hi Clare,
Good idea. I had her bring it over today where I cranked her up to 40psi on
all four tires. I'll keep an eye on it as I see her every day.

o Caster gauge (to measure caster & calculate camber)

You got that backwards - - - - You MEASURE camber and calculate
caster (unless you have PROPER equipment which measures both)

Yeah. That was a thinko. Thanks for catching it. We measure camber, which
is then used to calculate caster, which isn't adjustable in many cases
anyway.

One tool I might also need is a leveling tool so that all four wheels are
on a screw-mounted plate. Do you have a recommendation for that tool?

It might take a REAL PRO to modify the camber properly likely require
installation of either camber plates or long lower control arms (or
offset bushings)

There is a difference between a tuneup and an engine overhaul, where the
caster, camber, and toe measurements will likely only result in the need
for changes if they're well off the spec, and if the OEM setup allows for
it.

For example, while you can measure anything, on the bimmer, the only thing
an OEM setup can change is rear camber & toe, and then front toe, in that
order - and that's it.

On Fri, 14 Jun 2019 12:58:31 +1000, Xeno wrote:

Use the term Steering Axis Inclination (SAI) as your vehicle likely does
not have kingpins.

Hi Xeno,
I typed up a super detailed response, after viewing every second of those
three videos, where the first and last seem to have the same graphics, and
the middle (whiteboard) one was a bit different - and where that wheelcam
shot of the tire literally bending away from the rim - and the temperature
methods of determining footprint on hard cornering were illuminating.

I hate losing data, but I lost it when the PC rebooted, so suffice to say I
appreciate the videos, from which I learned good stuff, particularly about
that "scrub radius".

I didn't find a lot on the net about "camber scrub", and those videos
didn't cover specific tire wear on the slow speed (less than 40mph)
constantly lock-to-lock turns we perform on the mountain, where the goal
is how to modify the set up for the vehicle in a compromise to minimize
that 'camber scrub' on FWD and RWD vehicles without adversely affecting
straight-line handling.

Yes, that is basically all the small service station had next door to
where I did my apprenticeship. You have missed the primary requisite
however - a guaranteed dead flat and level garage floor. Also a lock to
lock the steering wheel to the desired centre position;
https://i.ebayimg.com/images/g/sJIAA...58p/s-l225.jpg


Everyone says you need a perfectly flat garage floor, which, as far as I
know, mine is pretty flat based on putting a level on it - but I don't
really know how flat is flat enough.

Given that a millimeter or two of height adjustment in any one corner might
be necessary for most garages, I guess your suggestion above adds two
nice-to-have tools to the home DIY alignment check mix...
o Steering wheel centering lock
o Some kind of way to put the 4 wheels on a wormscrew-adjusted plate

Googling found the first, but the second was in the thousand dollar range.

Are there good redneck solutions for leveling the four tires?

Ed Pawlowski posted for all of us...



On 6/12/2019 4:43 PM, devnull wrote:
On 6/12/19 4:17 PM, Ed Pawlowski wrote:
On 6/12/2019 6:24 AM, devnull wrote:
On 6/12/19 1:52 AM, Arlen G. Holder wrote:
she was in a rush so we did it in
about 20 minutes from start to finish.

Now that's a quickie!


Yeah, but it was 19 minutes foreplay.


If the nuts are rusty, sometimes you got to heat up the stud to get them
off.


Better than having them bleed
https://nypost.com/2019/06/11/florid...hey-bled-cops/

Remember Lorena Bobbitt? (How appropriate is the last name? 8~(

--
Tekkie

Clare Snyder posted for all of us...



On Wed, 12 Jun 2019 05:52:33 -0000 (UTC), "Arlen G. Holder"
wrote:

Clare - are smaller car tires easier to balance than SUV tires?
https://i.postimg.cc/kG1M7cLd/mount15.jpg

A neighbor was in need of tires who knew that I had bought a few extra for
her long ago where they've been sitting outside in the rain & mud for
months waiting for her to need them.
https://i.postimg.cc/7L8HPbtb/mount16.jpg

She finally wore through the belts and had to stop over for an "emergency"
tire change, which I did for her, but she was in a rush so we did it in
about 20 minutes from start to finish.

I had to do it so fast that I didn't see the yellow dot until I looked at
this picture, where I mounted the red dot to the valve stem instead of the
yellow dot as you had recommended for when there are no match mounting
marks.

I did statically balance and she reported no vibration whatsoever. I didn't
spend a lot of time cleaning up things so I'm surprised there's no
imbalance given how quickly I did the job for her.

Just wondering if you've found that these tiny 14-inch tires are a piece of
cake compared to the normal truck SUV tires (like the Optimo's that I'm
used to) both in terms of mounting and balancing?


Yes and no. The smaller tire has less total mass so a small amount
of weight has more effect than it would on a bigger tire - but it is
not as far from the center (shorter moment arm) so it has less effect.

GOOD tires of any size are easier to ballance than crappy tires. Ealy
Hankooks were a real pain to ballance. Apparentlythey have gotten
better.

I had a set of early Hankooks and could not get rid of the vibration. IIRC I
got Conti's with very good results.

--
Tekkie

Clare Snyder posted for all of us...



Running the dang things half flat or cornering like an idiot - - -


Looked to me to be major under-inflation.

--
Tekkie

Arlen G. Holder posted for all of us...



I have two more tires to put on for her for her rears, which are worn more
evenly (she probably doesn't rotate?) so I told her to wait until she
needed them since they are just sitting outside (I moved them into the
garage as they were getting dirty in the rain over the winter).


The better tires should-by tire manufacturers recommendation-be mounted on
the back.

--
Tekkie

On Fri, 14 Jun 2019 16:44:46 -0000 (UTC), "Arlen G. Holder"
wrote:

On Thu, 13 Jun 2019 21:17:18 -0400, Clare Snyder wrote:

I'd be cranking in a couple degrees of negative camber for extensive
downhill twisties. And running about 36PSI minimum pressure in the
front tires.

Hi Clare,
Good idea. I had her bring it over today where I cranked her up to 40psi on
all four tires. I'll keep an eye on it as I see her every day.

o Caster gauge (to measure caster & calculate camber)

You got that backwards - - - - You MEASURE camber and calculate
caster (unless you have PROPER equipment which measures both)

Yeah. That was a thinko. Thanks for catching it. We measure camber, which
is then used to calculate caster, which isn't adjustable in many cases
anyway.

One tool I might also need is a leveling tool so that all four wheels are
on a screw-mounted plate. Do you have a recommendation for that tool?

It might take a REAL PRO to modify the camber properly likely require
installation of either camber plates or long lower control arms (or
offset bushings)

There is a difference between a tuneup and an engine overhaul, where the
caster, camber, and toe measurements will likely only result in the need
for changes if they're well off the spec, and if the OEM setup allows for
it.

For example, while you can measure anything, on the bimmer, the only thing
an OEM setup can change is rear camber & toe, and then front toe, in that
order - and that's it.
What kind of heap is she driving????

On Fri, 14 Jun 2019 16:55:19 -0000 (UTC), "Arlen G. Holder"
wrote:

On Fri, 14 Jun 2019 12:58:31 +1000, Xeno wrote:

Use the term Steering Axis Inclination (SAI) as your vehicle likely does
not have kingpins.

Hi Xeno,
I typed up a super detailed response, after viewing every second of those
three videos, where the first and last seem to have the same graphics, and
the middle (whiteboard) one was a bit different - and where that wheelcam
shot of the tire literally bending away from the rim - and the temperature
methods of determining footprint on hard cornering were illuminating.

I hate losing data, but I lost it when the PC rebooted, so suffice to say I
appreciate the videos, from which I learned good stuff, particularly about
that "scrub radius".

I didn't find a lot on the net about "camber scrub", and those videos
didn't cover specific tire wear on the slow speed (less than 40mph)
constantly lock-to-lock turns we perform on the mountain, where the goal
is how to modify the set up for the vehicle in a compromise to minimize
that 'camber scrub' on FWD and RWD vehicles without adversely affecting
straight-line handling.

Yes, that is basically all the small service station had next door to
where I did my apprenticeship. You have missed the primary requisite
however - a guaranteed dead flat and level garage floor. Also a lock to
lock the steering wheel to the desired centre position;
https://i.ebayimg.com/images/g/sJIAA...58p/s-l225.jpg


Everyone says you need a perfectly flat garage floor, which, as far as I
know, mine is pretty flat based on putting a level on it - but I don't
really know how flat is flat enough.

Given that a millimeter or two of height adjustment in any one corner might
be necessary for most garages, I guess your suggestion above adds two
nice-to-have tools to the home DIY alignment check mix...
o Steering wheel centering lock
o Some kind of way to put the 4 wheels on a wormscrew-adjusted plate

Googling found the first, but the second was in the thousand dollar range.

Are there good redneck solutions for leveling the four tires?
A concrete grinder and a laser level

On Fri, 14 Jun 2019 14:51:53 -0400, Tekkie®
wrote:

Clare Snyder posted for all of us...



On Wed, 12 Jun 2019 05:52:33 -0000 (UTC), "Arlen G. Holder"
wrote:

Clare - are smaller car tires easier to balance than SUV tires?
https://i.postimg.cc/kG1M7cLd/mount15.jpg

A neighbor was in need of tires who knew that I had bought a few extra for
her long ago where they've been sitting outside in the rain & mud for
months waiting for her to need them.
https://i.postimg.cc/7L8HPbtb/mount16.jpg

She finally wore through the belts and had to stop over for an "emergency"
tire change, which I did for her, but she was in a rush so we did it in
about 20 minutes from start to finish.

I had to do it so fast that I didn't see the yellow dot until I looked at
this picture, where I mounted the red dot to the valve stem instead of the
yellow dot as you had recommended for when there are no match mounting
marks.

I did statically balance and she reported no vibration whatsoever. I didn't
spend a lot of time cleaning up things so I'm surprised there's no
imbalance given how quickly I did the job for her.

Just wondering if you've found that these tiny 14-inch tires are a piece of
cake compared to the normal truck SUV tires (like the Optimo's that I'm
used to) both in terms of mounting and balancing?


Yes and no. The smaller tire has less total mass so a small amount
of weight has more effect than it would on a bigger tire - but it is
not as far from the center (shorter moment arm) so it has less effect.

GOOD tires of any size are easier to ballance than crappy tires. Ealy
Hankooks were a real pain to ballance. Apparentlythey have gotten
better.

I had a set of early Hankooks and could not get rid of the vibration. IIRC I
got Conti's with very good results.
Could never figure out exactly how many corners Hankook figured
there were in a circle - - - -

On Fri, 14 Jun 2019 15:05:56 -0400, Tekkie®
wrote:

Arlen G. Holder posted for all of us...



I have two more tires to put on for her for her rears, which are worn more
evenly (she probably doesn't rotate?) so I told her to wait until she
needed them since they are just sitting outside (I moved them into the
garage as they were getting dirty in the rain over the winter).


The better tires should-by tire manufacturers recommendation-be mounted on
the back.
That is only true for ONE risk - the risk of the rear tires breaking
away on a corner due to hydroplaning or poor traction.

In his case if he always put the best tires on the rear he would
continually be putting half worn tires on the axle that is eating
tires and requires the most traction (the downhill steering wheels and
the uphill "scrambling" wheels.

Doesn't make a LICK of sense in either case.

On 15/6/19 7:04 am, Clare Snyder wrote:
On Fri, 14 Jun 2019 15:05:56 -0400, Tekkie®
wrote:

Arlen G. Holder posted for all of us...



I have two more tires to put on for her for her rears, which are worn more
evenly (she probably doesn't rotate?) so I told her to wait until she
needed them since they are just sitting outside (I moved them into the
garage as they were getting dirty in the rain over the winter).


The better tires should-by tire manufacturers recommendation-be mounted on
the back.
That is only true for ONE risk - the risk of the rear tires breaking
away on a corner due to hydroplaning or poor traction.

In his case if he always put the best tires on the rear he would
continually be putting half worn tires on the axle that is eating
tires and requires the most traction (the downhill steering wheels and
the uphill "scrambling" wheels.

Doesn't make a LICK of sense in either case.

The best tyres to the rear is for handling, keep the oversteer under
control. In that case, we're referring to the best *type* of tyre.
Radial versus crossply or steel belted radial versus textile radial.
Most run steel radials now so the basic premise is academic but the
basic rule is the best handling tyre when mixing tyre types.
When it comes to tread depth, yes, you are dealing then with the risk of
aquaplaning. More weight on the front means better water removal even on
lower tread depths. At the rear, on a FWD, there may be very minimal
mass on the rear tyres so pushing through water may be more difficult.
In summary, the best place for the newest tyres on a FWD is the rear.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

On Sat, 15 Jun 2019 09:55:05 +1000, Xeno
wrote:

On 15/6/19 7:04 am, Clare Snyder wrote:
On Fri, 14 Jun 2019 15:05:56 -0400, Tekkie®
wrote:

Arlen G. Holder posted for all of us...



I have two more tires to put on for her for her rears, which are worn more
evenly (she probably doesn't rotate?) so I told her to wait until she
needed them since they are just sitting outside (I moved them into the
garage as they were getting dirty in the rain over the winter).


The better tires should-by tire manufacturers recommendation-be mounted on
the back.
That is only true for ONE risk - the risk of the rear tires breaking
away on a corner due to hydroplaning or poor traction.

In his case if he always put the best tires on the rear he would
continually be putting half worn tires on the axle that is eating
tires and requires the most traction (the downhill steering wheels and
the uphill "scrambling" wheels.

Doesn't make a LICK of sense in either case.

The best tyres to the rear is for handling, keep the oversteer under
control. In that case, we're referring to the best *type* of tyre.
Radial versus crossply or steel belted radial versus textile radial.
Most run steel radials now so the basic premise is academic but the
basic rule is the best handling tyre when mixing tyre types.

NOT.

You NEVER mix types from axle to axle - for MANY reasons - one of
which is legal.
When it comes to tread depth, yes, you are dealing then with the risk of
aquaplaning. More weight on the front means better water removal even on
lower tread depths. At the rear, on a FWD, there may be very minimal
mass on the rear tyres so pushing through water may be more difficult.
In summary, the best place for the newest tyres on a FWD is the rear.

For cornering in wet weather or loose surfaces, yes. For powering
through corners or straight-line accelleration on clean dry pavement?
Mabee not.

Anywhere understeer is a possible problem , more than oversteer, you
want the best rubber on the front. On a FWD vehicle it is quite
difficult to induce oversteer to combat understeer - and FWD vehicles
tend towards understeer where you do NOT want bald front tires - - - .
On SEVERE trailing throttle you don't want bald tires on the rear
either.

Personally, I virtually ALWAYS replace tires in sets of 4 - and WELL
before the thread is gone !!! I don't put miles on fast enough any
more to wear good tires out before they "time out"

"Xeno" wrote in message
...
On 15/6/19 7:04 am, Clare Snyder wrote:
On Fri, 14 Jun 2019 15:05:56 -0400, Tekkie®
wrote:

Arlen G. Holder posted for all of us...



I have two more tires to put on for her for her rears, which are worn
more
evenly (she probably doesn't rotate?) so I told her to wait until she
needed them since they are just sitting outside (I moved them into the
garage as they were getting dirty in the rain over the winter).


The better tires should-by tire manufacturers recommendation-be mounted
on
the back.
That is only true for ONE risk - the risk of the rear tires breaking
away on a corner due to hydroplaning or poor traction.

In his case if he always put the best tires on the rear he would
continually be putting half worn tires on the axle that is eating
tires and requires the most traction (the downhill steering wheels and
the uphill "scrambling" wheels.

Doesn't make a LICK of sense in either case.

The best tyres to the rear is for handling, keep the oversteer under
control. In that case, we're referring to the best *type* of tyre. Radial
versus crossply or steel belted radial versus textile radial. Most run
steel radials now so the basic premise is academic but the basic rule is
the best handling tyre when mixing tyre types.
When it comes to tread depth, yes, you are dealing then with the risk of
aquaplaning. More weight on the front means better water removal even on
lower tread depths. At the rear, on a FWD, there may be very minimal mass
on the rear tyres so pushing through water may be more difficult.
In summary, the best place for the newest tyres on a FWD is the rear.

otoh you dont see a fwd aquaplane much at all even with the tires
with the least tread on the rear wheels.

On 15/6/19 2:55 am, Arlen G. Holder wrote:
On Fri, 14 Jun 2019 12:58:31 +1000, Xeno wrote:

Use the term Steering Axis Inclination (SAI) as your vehicle likely does
not have kingpins.

Hi Xeno,
I typed up a super detailed response, after viewing every second of those
three videos, where the first and last seem to have the same graphics, and
the middle (whiteboard) one was a bit different - and where that wheelcam
shot of the tire literally bending away from the rim - and the temperature
methods of determining footprint on hard cornering were illuminating.

Yes, I learnt a couple of points from those videos too so it seems you
can teach old dogs new tricks. I have found, in order to gain a better
appreciation of steering geometry and suspension systems, one needs to
look at those places that are extreme. In this case, it's in motor racing.

I hate losing data, but I lost it when the PC rebooted, so suffice to say I
appreciate the videos, from which I learned good stuff, particularly about
that "scrub radius".

I didn't find a lot on the net about "camber scrub", and those videos

You won't. Information on it is scarce since it is an undesired effect.
However, if you look at what the wheel is doing vis a vis camber during
high angle (note - not high speed) cornering, then you can visualise the
issue. Note too that tread blocks have a limited degree of flexibility
and, as such, are likely to exceed that during high angle cornering
resulting in tread scrubbing.

didn't cover specific tire wear on the slow speed (less than 40mph)
constantly lock-to-lock turns we perform on the mountain, where the goal
is how to modify the set up for the vehicle in a compromise to minimize
that 'camber scrub' on FWD and RWD vehicles without adversely affecting
straight-line handling.

The reality is that you are faced with a *compromise* and there are many
such in steering and suspension geometry. Any gain in the tyre wear
scenario will negatively affect high speed. If you happen to see a
Porsche Cayenne in a parking lot with its wheels turned at a high angle,
the camber angle displayed will amaze you. I know it amazed me. Of
course, when you realise that vehicle's suspension is *optimised* for
high speed and high power operation in a very narrow band either side of
straight ahead, it all makes sense.

Yes, that is basically all the small service station had next door to
where I did my apprenticeship. You have missed the primary requisite
however - a guaranteed dead flat and level garage floor. Also a lock to
lock the steering wheel to the desired centre position;
https://i.ebayimg.com/images/g/sJIAA...58p/s-l225.jpg


Everyone says you need a perfectly flat garage floor, which, as far as I
know, mine is pretty flat based on putting a level on it - but I don't
really know how flat is flat enough.

A level will only give you a localised point. You need something that
can verify any point in the garage floor against a common datum point.
These can be used for that purpose and aren't expensive;
https://www.bosch-do-it.com/au/en/di...898-199931.jsp
Or you could hire one for a day just to verify your garage floor. A
professional one of these should have been used when the floor was
poured and leveled anyway.

Given that a millimeter or two of height adjustment in any one corner might
be necessary for most garages, I guess your suggestion above adds two
nice-to-have tools to the home DIY alignment check mix...
o Steering wheel centering lock
o Some kind of way to put the 4 wheels on a wormscrew-adjusted plate

Googling found the first, but the second was in the thousand dollar range.

Are there good redneck solutions for leveling the four tires?

Most wheel aligners that I have used come with ramps that have the added
benefit of raising the vehicle a couple of feet off the floor. Ramps,
even without the aligner heads, provide a relatively easy means of
leveling the required work area. They don't even need to be raised more
than an inch or two. If the floor area is really out of whack, two or
four ramps made of wood of varying thicknesses might suffice. You can
even check the level easily these days with laser levels as I mentioned
above. My brother has one of the professional units since he is a
concreter but cheaper DIY versions, like the one in the link, should
suffice for this purpose.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

On 15/6/19 10:30 am, Clare Snyder wrote:
On Sat, 15 Jun 2019 09:55:05 +1000, Xeno
wrote:

On 15/6/19 7:04 am, Clare Snyder wrote:
On Fri, 14 Jun 2019 15:05:56 -0400, Tekkie®
wrote:

Arlen G. Holder posted for all of us...



I have two more tires to put on for her for her rears, which are worn more
evenly (she probably doesn't rotate?) so I told her to wait until she
needed them since they are just sitting outside (I moved them into the
garage as they were getting dirty in the rain over the winter).


The better tires should-by tire manufacturers recommendation-be mounted on
the back.
That is only true for ONE risk - the risk of the rear tires breaking
away on a corner due to hydroplaning or poor traction.

In his case if he always put the best tires on the rear he would
continually be putting half worn tires on the axle that is eating
tires and requires the most traction (the downhill steering wheels and
the uphill "scrambling" wheels.

Doesn't make a LICK of sense in either case.

The best tyres to the rear is for handling, keep the oversteer under
control. In that case, we're referring to the best *type* of tyre.
Radial versus crossply or steel belted radial versus textile radial.
Most run steel radials now so the basic premise is academic but the
basic rule is the best handling tyre when mixing tyre types.

NOT.

You NEVER mix types from axle to axle - for MANY reasons - one of
which is legal.

Yes, I am well aware of that but it used to be legal, within limits, and
some unknowing individuals still do it.

When it comes to tread depth, yes, you are dealing then with the risk of
aquaplaning. More weight on the front means better water removal even on
lower tread depths. At the rear, on a FWD, there may be very minimal
mass on the rear tyres so pushing through water may be more difficult.
In summary, the best place for the newest tyres on a FWD is the rear.

For cornering in wet weather or loose surfaces, yes. For powering
through corners or straight-line accelleration on clean dry pavement?
Mabee not.

Anywhere understeer is a possible problem , more than oversteer, you
want the best rubber on the front. On a FWD vehicle it is quite
difficult to induce oversteer to combat understeer - and FWD vehicles
tend towards understeer where you do NOT want bald front tires - - - .

I am not referring to *bald* tyres. I don't even let my tyres get to the
wear indicators as a rule. I like wet weather handling to be as optimal
as possible.

On SEVERE trailing throttle you don't want bald tires on the rear
either.

You do not want *bald* tyres anywhere on a vehicle. I am not referring
to bald tyres, just relative tread depth.

Personally, I virtually ALWAYS replace tires in sets of 4 - and WELL
before the thread is gone !!! I don't put miles on fast enough any
more to wear good tires out before they "time out"

As I said before, ditto for me. I do clock up the mileage however. I am
25-30% above average mileage now in my 3 year old car.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

On 15/6/19 11:39 am, Rod Speed wrote:


"Xeno" wrote in message
...
On 15/6/19 7:04 am, Clare Snyder wrote:
On Fri, 14 Jun 2019 15:05:56 -0400, Tekkie®
wrote:

Arlen G. Holder posted for all of us...



I have two more tires to put on for her for her rears, which are
worn more
evenly (she probably doesn't rotate?) so I told her to wait until she
needed them since they are just sitting outside (I moved them into the
garage as they were getting dirty in the rain over the winter).


The better tires should-by tire manufacturers recommendation-be
mounted on
the back.
Â*Â* That is only true for ONE risk - the risk of the rear tires breaking
away on a corner due to hydroplaning or poor traction.

In his case if he always put the best tires on the rear he would
continually be putting half worn tires on the axle that is eating
tires and requires the most traction (the downhill steering wheels and
the uphill "scrambling" wheels.

Doesn't make a LICK of sense in either case.

The best tyres to the rear is for handling, keep the oversteer under
control. In that case, we're referring to the best *type* of tyre.
Radial versus crossply or steel belted radial versus textile radial.
Most run steel radials now so the basic premise is academic but the
basic rule is the best handling tyre when mixing tyre types.
When it comes to tread depth, yes, you are dealing then with the risk
of aquaplaning. More weight on the front means better water removal
even on lower tread depths. At the rear, on a FWD, there may be very
minimal mass on the rear tyres so pushing through water may be more
difficult.
In summary, the best place for the newest tyres on a FWD is the rear.

otoh you dont see a fwd aquaplane much at all even with the tires
with the least tread on the rear wheels.

It is the manufacturers who are recommending newest to the rears. I
understand their logic since I also understand the handling dynamics of
a car.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

"Xeno" wrote in message
...
On 15/6/19 11:39 am, Rod Speed wrote:


"Xeno" wrote in message
...
On 15/6/19 7:04 am, Clare Snyder wrote:
On Fri, 14 Jun 2019 15:05:56 -0400, Tekkie®
wrote:

Arlen G. Holder posted for all of us...



I have two more tires to put on for her for her rears, which are worn
more
evenly (she probably doesn't rotate?) so I told her to wait until she
needed them since they are just sitting outside (I moved them into
the
garage as they were getting dirty in the rain over the winter).


The better tires should-by tire manufacturers recommendation-be
mounted on
the back.
That is only true for ONE risk - the risk of the rear tires breaking
away on a corner due to hydroplaning or poor traction.

In his case if he always put the best tires on the rear he would
continually be putting half worn tires on the axle that is eating
tires and requires the most traction (the downhill steering wheels and
the uphill "scrambling" wheels.

Doesn't make a LICK of sense in either case.

The best tyres to the rear is for handling, keep the oversteer under
control. In that case, we're referring to the best *type* of tyre.
Radial versus crossply or steel belted radial versus textile radial.
Most run steel radials now so the basic premise is academic but the
basic rule is the best handling tyre when mixing tyre types.
When it comes to tread depth, yes, you are dealing then with the risk of
aquaplaning. More weight on the front means better water removal even on
lower tread depths. At the rear, on a FWD, there may be very minimal
mass on the rear tyres so pushing through water may be more difficult.
In summary, the best place for the newest tyres on a FWD is the rear.

otoh you dont see a fwd aquaplane much at all even with the tires
with the least tread on the rear wheels.

It is the manufacturers who are recommending newest to the rears.

But given that I dont see any aquaplaning with the rear wheels on my FWD,
I dont buy their recommendation. Clare's comment covers that well.

I understand their logic since I also understand the handling dynamics of
a car.

Not with aquaplaning on the rear wheels of FWD cars you dont.

On Sat, 15 Jun 2019 16:16:41 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


It is the manufacturers who are recommending newest to the rears.

But given that I don¢t see any aquaplaning with the rear wheels on my FWD,
I don¢t buy their recommendation.

Of COURSE not, auto-contradicting senile Rodent! LOL

--
Kerr-Mudd,John addressing senile Rot:
"Auto-contradictor Rod is back! (in the KF)"
MID:

On Sat, 15 Jun 2019 11:39:38 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

lower tread depths. At the rear, on a FWD, there may be very minimal mass
on the rear tyres so pushing through water may be more difficult.
In summary, the best place for the newest tyres on a FWD is the rear.

otoh you don¢t see a fwd aquaplane much at all even with the tires
with the least tread on the rear wheels.

In auto-contradicting mode again, senile asshole? LOL

--
Kerr-Mudd,John addressing senile Rot:
"Auto-contradictor Rod is back! (in the KF)"
MID:

On 15/6/19 4:16 pm, Rod Speed wrote:


"Xeno" wrote in message
...
On 15/6/19 11:39 am, Rod Speed wrote:


"Xeno" wrote in message
...
On 15/6/19 7:04 am, Clare Snyder wrote:
On Fri, 14 Jun 2019 15:05:56 -0400, Tekkie®
wrote:

Arlen G. Holder posted for all of us...



I have two more tires to put on for her for her rears, which are
worn more
evenly (she probably doesn't rotate?) so I told her to wait until
she
needed them since they are just sitting outside (I moved them
into the
garage as they were getting dirty in the rain over the winter).


The better tires should-by tire manufacturers recommendation-be
mounted on
the back.
Â*Â* That is only true for ONE risk - the risk of the rear tires
breaking
away on a corner due to hydroplaning or poor traction.

In his case if he always put the best tires on the rear he would
continually be putting half worn tires on the axle that is eating
tires and requires the most traction (the downhill steering wheels and
the uphill "scrambling" wheels.

Doesn't make a LICK of sense in either case.

The best tyres to the rear is for handling, keep the oversteer under
control. In that case, we're referring to the best *type* of tyre.
Radial versus crossply or steel belted radial versus textile radial.
Most run steel radials now so the basic premise is academic but the
basic rule is the best handling tyre when mixing tyre types.
When it comes to tread depth, yes, you are dealing then with the
risk of aquaplaning. More weight on the front means better water
removal even on lower tread depths. At the rear, on a FWD, there may
be very minimal mass on the rear tyres so pushing through water may
be more difficult.
In summary, the best place for the newest tyres on a FWD is the rear.

otoh you dont see a fwd aquaplane much at all even with the tires
with the least tread on the rear wheels.

It is the manufacturers who are recommending newest to the rears.

But given that I dont see any aquaplaning with the rear wheels on my FWD,
I dont buy their recommendation. Clare's comment covers that well.

I understand their logic since I also understand the handling dynamics
of a car.

Not with aquaplaning on the rear wheels of FWD cars you dont.

Did I not say that it isn't just for *aquaplaning*? The idea is to
reduce slip angles at the rear to control oversteer tendencies. This is
all the time, not just when aquaplaning. All cars are designed with
inbuilt understeer - even rear wheel drive cars. If you want to argue
the toss, then take it up with the tyre manufacturers. After all, it's
their recommendation for their own product so I feel safe in assuming
they would have a better idea than Joe Blow off the street.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

On Sat, 15 Jun 2019 14:24:27 +1000, Xeno
wrote:

On 15/6/19 10:30 am, Clare Snyder wrote:


You NEVER mix types from axle to axle - for MANY reasons - one of
which is legal.

Yes, I am well aware of that but it used to be legal, within limits, and
some unknowing individuals still do it.
OI t was illegal already back in 1969

"Xeno" wrote in message
...
On 15/6/19 4:16 pm, Rod Speed wrote:


"Xeno" wrote in message
...
On 15/6/19 11:39 am, Rod Speed wrote:


"Xeno" wrote in message
...
On 15/6/19 7:04 am, Clare Snyder wrote:
On Fri, 14 Jun 2019 15:05:56 -0400, Tekkie®
wrote:

Arlen G. Holder posted for all of us...



I have two more tires to put on for her for her rears, which are
worn more
evenly (she probably doesn't rotate?) so I told her to wait until
she
needed them since they are just sitting outside (I moved them into
the
garage as they were getting dirty in the rain over the winter).


The better tires should-by tire manufacturers recommendation-be
mounted on
the back.
That is only true for ONE risk - the risk of the rear tires
breaking
away on a corner due to hydroplaning or poor traction.

In his case if he always put the best tires on the rear he would
continually be putting half worn tires on the axle that is eating
tires and requires the most traction (the downhill steering wheels
and
the uphill "scrambling" wheels.

Doesn't make a LICK of sense in either case.

The best tyres to the rear is for handling, keep the oversteer under
control. In that case, we're referring to the best *type* of tyre.
Radial versus crossply or steel belted radial versus textile radial.
Most run steel radials now so the basic premise is academic but the
basic rule is the best handling tyre when mixing tyre types.
When it comes to tread depth, yes, you are dealing then with the risk
of aquaplaning. More weight on the front means better water removal
even on lower tread depths. At the rear, on a FWD, there may be very
minimal mass on the rear tyres so pushing through water may be more
difficult.
In summary, the best place for the newest tyres on a FWD is the rear.

otoh you dont see a fwd aquaplane much at all even with the tires
with the least tread on the rear wheels.

It is the manufacturers who are recommending newest to the rears.

But given that I dont see any aquaplaning with the rear wheels on my
FWD,
I dont buy their recommendation. Clare's comment covers that well.

I understand their logic since I also understand the handling dynamics
of a car.

Not with aquaplaning on the rear wheels of FWD cars you dont.

Did I not say that it isn't just for *aquaplaning*?

The other effects are even less likely.

The idea is to reduce slip angles at the rear to control oversteer
tendencies.

Oversteer just isnt a problem with fwd cars.

This is all the time, not just when aquaplaning. All cars are designed
with inbuilt understeer - even rear wheel drive cars.

fwd cars understeer regardless of the design.

If you want to argue the toss, then take it up with the tyre
manufacturers.

My tire manufacture isnt stupid enough to say that.

After all, it's their recommendation for their own product

It isnt with mine.

so I feel safe in assuming they would have a better idea than Joe Blow off
the street.

Its basic physics and trivial to prove that the
car doesnt do any better with the new tires
on the back with a fwd car.

On Sun, 16 Jun 2019 05:47:57 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


Its basic physics and trivial to prove that the
car doesn¢t do any better with the new tires
on the back with a fwd car.

What could be more trivial than your senile trolling on all these groups,
you abnormal senile pest?

--
FredXX to Rot Speed:
"You are still an idiot and an embarrassment to your country. No wonder
we shipped the likes of you out of the British Isles. Perhaps stupidity
and criminality is inherited after all?"
Message-ID:

On 16/6/19 3:46 am, Clare Snyder wrote:
On Sat, 15 Jun 2019 14:24:27 +1000, Xeno
wrote:

On 15/6/19 10:30 am, Clare Snyder wrote:


You NEVER mix types from axle to axle - for MANY reasons - one of
which is legal.

Yes, I am well aware of that but it used to be legal, within limits, and
some unknowing individuals still do it.
OI t was illegal already back in 1969

It wasn't illegal in this country back in 1969. There were specific
limits to what you could do but the only legal requirement, as I recall,
was the tyres had to be the same on the same *axle*.

I found, even though you could in that era have different tread patterns
front to rear, you needed to ensure the best *handling* tyre was at the
rear. This was not always easy to determine as I found out when I
couldn't buy tyres to match the tread pattern on a car I owned and
bought two tyres which looked very similar tread wise to the existing
pair. Both types were textile radials and I fitted the new ones to the
front. The rear tyre tread depth was very close to that of the new front
tyres. What I found however was that the new tyres were way too precise
with very low slip angles. When in even moderate cornering situations,
the front would spear into a corner with minimal understeer
characteristics whilst the rear displayed tail happy behaviour. The car
felt *pigeon toed* as if the front wheels had extreme toe in settings. I
couldn't leave it like that because my wife was the primary driver of
that car so I reversed the set and it made the car stable once more. Not
long afterwards I bought another 2 tyres and matched the existing new
ones to give much more balanced handling and used the originals on a
trailer. Whilst it appeared only to be a tread pattern difference, it
soon became obvious that handling characteristics were vastly different
between the two types and probably involved much more than the tread
pattern alone. It wasn't possible to deduce this from merely looking at
the tyres, it required a run on the road to discern the characteristics.

When I first entered the automotive industry, crossply tyres were king
and radials were just entering general use. It was the recommendation at
that time, if mixing types, to place crossplies at the front, the
radials at the rear. As steel belted radials entered the scene, it was
recommended that, if mixing the two radial types, that the steel belted
radials were fitted to the rear and textile radials to the front. The
reasoning back then was simple - cross ply tyres had the greatest slip
angle characteristics, textile radials had lower slip angle
characteristics and steel belted radials had the lowest slip angle
characteristics of all. It was always mandatory to have tyres matched on
the same axle according to roadworthy laws but the front to rear
placement was Ok if you followed the above guidelines. As I found
however, it wasn't always that simple and there were situations which
were a case of try it and see. Since that time I have always bought
tyres as a set of four at a minimum, fitted them all at the same time
and followed tyre rotation procedures.

As for the legality of different tyres front to rear, some new vehicles
would fall afoul of that since they have a larger rim size at the rear,
usually in width but occasionally in diameter. Some small vans have a
larger diameter wheel at the front, a smaller on at the rear for a
flatter cargo space but, in these cases, the rear are *duals*.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

On Sat, 15 Jun 2019 14:14:27 +1000, Xeno wrote:

You won't. Information on it is scarce since it is an undesired effect.
However, if you look at what the wheel is doing vis a vis camber during
high angle (note - not high speed) cornering, then you can visualise the
issue. Note too that tread blocks have a limited degree of flexibility
and, as such, are likely to exceed that during high angle cornering
resulting in tread scrubbing.

Hi Xeno,

While I don't race, our conditions are "extreme" enough, in that constant
incessant repeated nearly full back-to-back wheel locks are causing
"something" to scrape away rubber, so this "camber scrub" is intriguing.

I snapped this photo of tires that I mounted about a month ago, which only
have about 1000 miles on them, where they clearly show this pattern which
"might" be what you've been referring to as "camber scrub".
https://i.postimg.cc/zvvyL2tq/mount24.jpg

Does _that_ feathering look like what you're referring to as "camber scrub"?

On 16/6/19 4:31 pm, Arlen G. Holder wrote:
On Sat, 15 Jun 2019 14:14:27 +1000, Xeno wrote:

You won't. Information on it is scarce since it is an undesired effect.
However, if you look at what the wheel is doing vis a vis camber during
high angle (note - not high speed) cornering, then you can visualise the
issue. Note too that tread blocks have a limited degree of flexibility
and, as such, are likely to exceed that during high angle cornering
resulting in tread scrubbing.

Hi Xeno,

While I don't race, our conditions are "extreme" enough, in that constant
incessant repeated nearly full back-to-back wheel locks are causing
"something" to scrape away rubber, so this "camber scrub" is intriguing.

That is also considered *extreme* even though you aren't doing it fast.

I snapped this photo of tires that I mounted about a month ago, which only
have about 1000 miles on them, where they clearly show this pattern which
"might" be what you've been referring to as "camber scrub".
https://i.postimg.cc/zvvyL2tq/mount24.jpg

Does _that_ feathering look like what you're referring to as "camber scrub"?

It does indeed! Same kind of feathering I'm getting on my Toyota's front
tyres - a feathering that you can easily feel in the early stages as you
run your hands for and aft along that section of tread area. Now try to
imagine what those tread blocks are doing as they roll around in a tight
circle with heaps of camber gain. It's not pretty and, worse, there is
SFA you can do about it.

BTW, positive caster will accentuate the camber scrub. Caster is
generally not a tyre wearing angle. However, the more caster your
steering has, the more camber *change* you will get when turning the
steering. Positive caster will give you a beneficial gain in terms of
handling. You will get more camber gain (more +ve) on the inside wheel
but the outside wheel will experience camber *loss* and become more
vertical or even negative. Since the more vertical tyre is on the
outside, the tread will get more grip with reduced slip angle aided by
weight transfer. This is great for cornering at speed. However when
travelling at slow speeds, weight transfer is not as significant and the
camber angle on the inside wheel, the one at the tightest lock, heads
towards positive extremes. It is, in effect, riding heavily on the outer
edge of the tread and this is where, and why, the damage is being done.
The tread blocks have only so much flex before they are forced to break
contact with the road and slide. You've seen the evidence of what that does.

Caster specifications are usually given as a range, say between 1 and 2
degrees with a side to side variation limit. All you can really do to
mitigate the effect is to set your caster to the low end of the
specified range.



--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)