On Thu, 28 Jun 2018 19:24:21 +0100, "dennis@home"
wrote:

On 28/06/2018 16:40, Tim Streater wrote:
In article , "dennis@home" wrote:

On 28/06/2018 10:59, The Natural Philosopher wrote:

What I wouuld ask you is how a tyre, rotating at a differentent rate
from a wheel, so that its circumference does in fact get covered on
the ground by that rotaion, stays on the wheel without ripping the
tread off?

This "philosopher" hasn't ever noticed the tyre debris on the roads
where the tread has been ripped off.

Maybe he wants to explain why it happens to lorries with twin wheels
where only one tyre has gone flat but is being kept at about the
correct radius by the other wheel?

Ah, nice attempt at a shimmy there, Den. Our Dave would be proud of you.

What you're in fact admitting is that the wheel and the tire *must*
rotate at the same rate, otherwise the tread would come off.


How dumb can you be to think that is what I said?
I said the exact opposite of what you chose to claim I said.

Are you TNP ?

No, he is Turnips goblin and they obviously stick together in the
false sense that there is safety in numbers.

All that actually means ITRW is they will all fall into the moat at
the same time. ;-)

And the same freaks think they have all the answers to Brexit!

Cheers, T i m

The Natural Philosopher wrote:

we don't disagree that the rate changes. Only by how much

As there was nothing on telly tonight, I used my OBD cable to log the
four wheel speed sensors over a straight section of road with cruise
control set to 50mph, which was measured by VCDS as 77.6kph then let
some pressure out of the right rear, turned around, rinse and repeat
until the TPMS triggered.

Starting at 39psi the right rear was on average 0.1kph slower than the
other three wheels, it triggered after letting it down to 31psi by which
time it was on average 0.2kph faster than the other three wheels.

So it triggered on a increased wheel speed of 0.3/77.6 = 0.4%

and why.

The numbers don't help with that.

On Thu, 28 Jun 2018 16:20:07 +0100, "dennis@home"
wrote:

snip

Rubbish.

And most of the people (worth considering) agree.

The tread on the tyre and the side walls deform as the tyre rotates
changing the actual circumference.

Yup.

The change depends on the contact length which changes with pressure,
load, tread pattern, rubber compound, type of belts, etc.

Yup.

Even a steel tyre like those on trains deforms as it rotates.

Ere, tell Turnip and his goblin assistant (Streater) that a part of a
train goes backward as the train goes forward and watch their tiny
brains explode!

Cheers, T i m

"T i m" wrote in message
...

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either. Why would
the tyre 'spread more' as it gets flatter and why would the circumference
get shorter even if it did

A 27yr old girl gave the right answer instantly when the combined
brains of Turnip and his goblin Streater still cannot!

Bwhahahahahaha ... !!!

"Andy Burns" wrote in message
...
The Natural Philosopher wrote:

we don't disagree that the rate changes. Only by how much

As there was nothing on telly tonight, I used my OBD cable to log the four
wheel speed sensors over a straight section of road with cruise control
set to 50mph, which was measured by VCDS as 77.6kph then let some pressure
out of the right rear, turned around, rinse and repeat until the TPMS
triggered.

Starting at 39psi the right rear was on average 0.1kph slower than the
other three wheels, it triggered after letting it down to 31psi by which
time it was on average 0.2kph faster than the other three wheels.

So it triggered on a increased wheel speed of 0.3/77.6 = 0.4%

and why.

The numbers don't help with that.

They do in the sense that presumably the distance from the axle to the road
dropped
by rather more than the 0.4% that the ABS sensors recorded, so the effect
must
indeed be due to the circumference changing, not the dynamic rolling radius.

On Fri, 29 Jun 2018 06:48:50 +1000, "Jeff" wrote:



"Andy Burns" wrote in message
...
The Natural Philosopher wrote:

we don't disagree that the rate changes. Only by how much

As there was nothing on telly tonight, I used my OBD cable to log the four
wheel speed sensors over a straight section of road with cruise control
set to 50mph, which was measured by VCDS as 77.6kph then let some pressure
out of the right rear, turned around, rinse and repeat until the TPMS
triggered.

Starting at 39psi the right rear was on average 0.1kph slower than the
other three wheels, it triggered after letting it down to 31psi by which
time it was on average 0.2kph faster than the other three wheels.

So it triggered on a increased wheel speed of 0.3/77.6 = 0.4%

and why.

The numbers don't help with that.

They do in the sense that presumably the distance from the axle to the road
dropped
by rather more than the 0.4% that the ABS sensors recorded, so the effect
must
indeed be due to the circumference changing, not the dynamic rolling radius.

But the two are interlinked?

If you accept the circumference changes between the tyre carrying no
load, the tyre carrying load and inflated correctly and the tyre
running at a lower pressure, then in the first case there is a
conventional radius and in the last two, because the tyre is no longer
circular and because it shrinks under the footprint, we also have a
rolling radius.

What we can't say with any certainty is the actual distance between
the axle and the road is the same as the rolling radius (because by
definition the centre of the axle will be low of centre of the
effective circumference, simply because of how tyres work.

With iTPMS I believe some manufacturers shun (or shunned) it because
it is much more critical in it's calibration than the direct reading
TPMS.

A new tyre, tyre rotation, a managed change in pressure generally
require a 'reset' or the system could become unreliable. This is
considered 'too interactive by some manufacturers, having to rely on
human input to keep the system reliable.

This would confirm the concept of iTPMS working with very small
differences ... the sort you get when you change a tyre or get a
puncture. ;-)

Cheers, T i m

On Thu, 28 Jun 2018 21:19:41 +0100, Tim Streater
wrote:

In article , "dennis@home" wrote:

On 28/06/2018 16:40, Tim Streater wrote:
In article , "dennis@home" wrote:

On 28/06/2018 10:59, The Natural Philosopher wrote:

What I wouuld ask you is how a tyre, rotating at a differentent rate
from a wheel, so that its circumference does in fact get covered on
the ground by that rotaion, stays on the wheel without ripping the
tread off?

This "philosopher" hasn't ever noticed the tyre debris on the roads
where the tread has been ripped off.

Maybe he wants to explain why it happens to lorries with twin wheels
where only one tyre has gone flat but is being kept at about the
correct radius by the other wheel?

Ah, nice attempt at a shimmy there, Den. Our Dave would be proud of you.

What you're in fact admitting is that the wheel and the tire *must*
rotate at the same rate, otherwise the tread would come off.


How dumb can you be to think that is what I said?
I said the exact opposite of what you chose to claim I said.

Are you TNP ?

TNP says (above) that having a wheel rotating at a different rate to
the tire is only possible if the tread rips off.

And so he's talking BS.

You point out how much tire debris there is around.

For different reasons that you obviously don't have the IQ or interest
to understand.

QED.

Not to you it seems.

dennis quite clearly stated the scenario with a twin wheel lorry where
the 'effective circumferences' can become substantially different if
one tyre becomes deflated and *then* one tyre is likely to suffer
further damage. It's more likely to be the low pressure tyre because
it will be carrying less load and so more likely to scrub than the one
carrying all the load.

Except all this is just basic mechanics and common sense, not
characteristics generally found in 'artists' eh. ;-(

Cheers, T i m

On 28/06/2018 22:28, T i m wrote:

dennis quite clearly stated the scenario with a twin wheel lorry where
the 'effective circumferences' can become substantially different if
one tyre becomes deflated

Aren't twin lorry tyres linked by a pipe between the tyres? So they're
inflated as one?

On Thu, 28 Jun 2018 22:26:40 +0100, Tim Streater
wrote:

In article , Jeff
wrote:

"T i m" wrote in message
. ..

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either. Why would
the tyre 'spread more' as it gets flatter and why would the circumference
get shorter even if it did

Well it does spread a bit, see Fig 5 on:

http://the-contact-patch.com/book/road/c2020-the-contact-patch

But the circumference can't get shorter except for a small amount,

Bwhahaha ... what's this, the penny staring to drop with Turnips
goblin as well!!

much
less than the "rolling radius" people like Huge and T r o l l.

I personally haven't stated any numbers so even more BS and lies from
the goblin.

Fig 5 shows what *actually* happens when the tire is deflated (although
fig 5 is about higher speed effects, supposedly). You will see it
showing the bulge on each side of the flat part.

That is where the
extra circumference goes,

Ding! They all get there in the end ... even goblins!

Cheers, T i m

"T i m" wrote in message
news
On Fri, 29 Jun 2018 06:48:50 +1000, "Jeff" wrote:



"Andy Burns" wrote in message
...
The Natural Philosopher wrote:

we don't disagree that the rate changes. Only by how much

As there was nothing on telly tonight, I used my OBD cable to log the
four
wheel speed sensors over a straight section of road with cruise control
set to 50mph, which was measured by VCDS as 77.6kph then let some
pressure
out of the right rear, turned around, rinse and repeat until the TPMS
triggered.

Starting at 39psi the right rear was on average 0.1kph slower than the
other three wheels, it triggered after letting it down to 31psi by which
time it was on average 0.2kph faster than the other three wheels.

So it triggered on a increased wheel speed of 0.3/77.6 = 0.4%

and why.

The numbers don't help with that.

They do in the sense that presumably the distance from the axle to the
road
dropped
by rather more than the 0.4% that the ABS sensors recorded, so the effect
must
indeed be due to the circumference changing, not the dynamic rolling
radius.

But the two are interlinked?

Can't be by much given that you'd expect the axle to road distance to have
dropped by more than 0.4%, although he didn't actually measure that.

39psi is quite high so it may be a pretty big solid wheel and tyre, so
it would be interesting to have had that distance measured.

If you accept the circumference changes between the tyre carrying no
load, the tyre carrying load and inflated correctly and the tyre
running at a lower pressure, then in the first case there is a
conventional radius and in the last two, because the tyre is no longer
circular and because it shrinks under the footprint, we also have a
rolling radius.

What we can't say with any certainty is the actual distance between
the axle and the road is the same as the rolling radius (because by
definition the centre of the axle will be low of centre of the
effective circumference, simply because of how tyres work.

With iTPMS I believe some manufacturers shun (or shunned) it because
it is much more critical in it's calibration than the direct reading
TPMS.

A new tyre, tyre rotation, a managed change in pressure generally
require a 'reset' or the system could become unreliable. This is
considered 'too interactive by some manufacturers, having to rely on
human input to keep the system reliable.

But it should be possible to reset it automatically when it is clear
that a wheel has been changed, say because it had to be to pass the
MOT or the tyre pressure had been changed at the service station

This would confirm the concept of iTPMS working with very small
differences ... the sort you get when you change a tyre or get a
puncture. ;-)

A slow leak too.

On Fri, 29 Jun 2018 06:43:35 +1000, "Jeff" wrote:



"T i m" wrote in message
.. .

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either.

Then come up with a more credible one?

the tyre 'spread more' as it gets flatter and why would the circumference
get shorter even if it did

What part of 'pantographing' don't you get OOI?

Have you ever seen one of those expanding pop rivet guns ... of the
joke boxing glove on an expanding arm?

When those things get wider they get shorter.

Imagine one bent round into a circle (like the internal structure of a
tyre). What would you get if it was made out of flexible materials at
the flat section at the bottom, where the thing spreads out?

I really can't think of any other way to make it any simpler for you?

Cheers, T i m

Jeff wrote:

"T i m" wrote:

But the two are interlinked?

Can't be by much given that you'd expect the axle to road distance to have
dropped by more than 0.4%, although he didn't actually measure that.

I can drop the pressure back to 31 and measure the drop of the axle,
certainly it was visibly more than 0.4%, of course I won't be inside the
car adding weight while I measure it ...

On Fri, 29 Jun 2018 07:35:45 +1000, "Jeff" wrote:

snip

They do in the sense that presumably the distance from the axle to the
road
dropped
by rather more than the 0.4% that the ABS sensors recorded, so the effect
must
indeed be due to the circumference changing, not the dynamic rolling
radius.

But the two are interlinked?

Can't be by much given that you'd expect the axle to road distance to have
dropped by more than 0.4%, although he didn't actually measure that.

I didn't watch whatever you are referring to as it doesn't matter. I
don't need to because I know iTPMS does work and therefore the only
way it can work. ;-)

39psi is quite high so it may be a pretty big solid wheel and tyre, so
it would be interesting to have had that distance measured.

Possibly.

If you accept the circumference changes between the tyre carrying no
load, the tyre carrying load and inflated correctly and the tyre
running at a lower pressure, then in the first case there is a
conventional radius and in the last two, because the tyre is no longer
circular and because it shrinks under the footprint, we also have a
rolling radius.

What we can't say with any certainty is the actual distance between
the axle and the road is the same as the rolling radius (because by
definition the centre of the axle will be low of centre of the
effective circumference, simply because of how tyres work.

With iTPMS I believe some manufacturers shun (or shunned) it because
it is much more critical in it's calibration than the direct reading
TPMS.

A new tyre, tyre rotation, a managed change in pressure generally
require a 'reset' or the system could become unreliable. This is
considered 'too interactive by some manufacturers, having to rely on
human input to keep the system reliable.

But it should be possible to reset it automatically when it is clear
that a wheel has been changed, say because it had to be to pass the
MOT or the tyre pressure had been changed at the service station

Yup, possibly it could be automatic, especially if it could cross
reference the iTPMS with GPS etc.

This would confirm the concept of iTPMS working with very small
differences ... the sort you get when you change a tyre or get a
puncture. ;-)

A slow leak too.

Quite.

Cheers, T i m

On Thu, 28 Jun 2018 22:31:36 +0100, Andy Burns
wrote:

On 28/06/2018 22:28, T i m wrote:

dennis quite clearly stated the scenario with a twin wheel lorry where
the 'effective circumferences' can become substantially different if
one tyre becomes deflated

Aren't twin lorry tyres linked by a pipe between the tyres? So they're
inflated as one?

Some may be Andy but many I have seen have a long valve that brings
the rear tyre and if they were linked there wouldn't be any redundancy
would there (and that was part of the point).

A mate had a single wheel recovery truck and they banned them because
of the consequences of the only wheel failing on one side.

I'm sure there are linked systems these days, especially with the
introduction of TPMS etc?

Cheers, T i m

On Thu, 28 Jun 2018 22:42:18 +0100, Andy Burns
wrote:

Jeff wrote:

"T i m" wrote:

But the two are interlinked?

Can't be by much given that you'd expect the axle to road distance to have
dropped by more than 0.4%, although he didn't actually measure that.

I can drop the pressure back to 31 and measure the drop of the axle,
certainly it was visibly more than 0.4%,

I don't think anyone questions the fact the most of the load is
carried at the bottom of a tyre g and so it will be there more than
anywhere else that will change as the load increases or the pressure
drops. Personally I'm not suggesting there is a direct relationship
between the height of the axle over the road and the 'rolling radius'
but there could be.

of course I won't be inside the
car adding weight while I measure it ...

;-)

Cheers, T i m

On 28/06/2018 21:43, Jeff wrote:


"T i m" wrote in message
...

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either. Why would
the tyre 'spread more' as it gets flatter and why would the circumference
get shorter even if it did

Well that is the obvious bit, less pressure means more of the tyre has
to be in contact with the road to take the load.

The circumference of a tyre is not a fixed length.
Its flexible blocks (the tread) mounted on a flexible base mounted on a
flexible core of wires/nylon (the plys).

As the tyre hits the road the blocks get closer together so the
circumference decreases.

Even slicks compress because they usually use a soft rubber.

Shame TNP is so fixed he can't understand that this is too complex for
his closed mind.

On 28/06/2018 22:26, Tim Streater wrote:
In article , Jeff
wrote:

"T i m" wrote in message
...

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either. Why would
the tyre 'spread more' as it gets flatter and why would the circumference
get shorter even if it did

Well it does spread a bit, see Fig 5 on:

Â*http://the-contact-patch.com/book/road/c2020-the-contact-patch

But the circumference can't get shorter except for a small amount, much
less than the "rolling radius" people like Huge andÂ* T r o l l.

Fig 5 shows what *actually* happens when the tire is deflated (although
fig 5 is about higher speed effects, supposedly). You will see it
showing the bulge on each side of the flat part. That is where the
extra circumference goes, the part that supposedly vanishes according
to fig 6. AISB, fig 6 doesn't have anything to do with reality.


Why the sudden change? Now TNP has claimed that the circumference can
change you also change to say it can.

You are a mug if you think TNP is right all the time, he isn't.
And neither are you.

On 28/06/2018 21:19, Tim Streater wrote:
In article , "dennis@home" wrote:

On 28/06/2018 16:40, Tim Streater wrote:
In article , "dennis@home" wrote:

On 28/06/2018 10:59, The Natural Philosopher wrote:

What I wouuld ask you is how a tyre, rotating at a differentent
rate from a wheel, so that its circumference does in fact get
covered on the ground by that rotaion, stays on the wheel without
ripping the tread off?

This "philosopher" hasn't ever noticed the tyre debris on the roads
where the tread has been ripped off.

Maybe he wants to explain why it happens to lorries with twin wheels
where only one tyre has gone flat but is being kept at about the
correct radius by the other wheel?

Ah, nice attempt at a shimmy there, Den. Our Dave would be proud of you.

What you're in fact admitting is that the wheel and the tire *must*
rotate at the same rate, otherwise the tread would come off.


How dumb can you be to think that is what I said?
I said the exact opposite of what you chose to claim I said.

Are you TNP ?

TNP says (above) that having a wheel rotating at a different rate to
the tire is only possible if the tread rips off.

You point out how much tire debris there is around.

QED.


You are just hoping nobody bothers to think about what you claim.

TNP says if they rotate at different rates the treads fall off..
I say treads do fall of.
You think it means I am agreeing with TNP.

Just think for a second instead of parroting TNP..
The tread changes length when it hits the road so that bit of the tyre
is rotating at a different rate to the rest so yes tyres do rotate at
different rates to the wheel some bits at one rate some at another and
some at all the values in between.
Now sod off if you can't be bothered to think for yourself.

On 28/06/2018 22:31, Andy Burns wrote:
On 28/06/2018 22:28, T i m wrote:

dennis quite clearly stated the scenario with a twin wheel lorry where
the 'effective circumferences' can become substantially different if
one tyre becomes deflated

Aren't twin lorry tyres linked by a pipe between the tyres? So they're
inflated as one?

Certainly not all, I have seen them with the tread and cassing stripped
from one tyre and the other is still inflated.

"T i m" wrote in message
...
On Fri, 29 Jun 2018 06:43:35 +1000, "Jeff" wrote:



"T i m" wrote in message
. ..

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either.

Then come up with a more credible one?

I prefer to measure, not speculate.

the tyre 'spread more' as it gets flatter and why would the circumference
get shorter even if it did

What part of 'pantographing' don't you get OOI?

I've never been convinced by your pantograph line.
The steel belts arent panto graphs.

Have you ever seen one of those expanding pop rivet guns ... of the
joke boxing glove on an expanding arm?

When those things get wider they get shorter.

Yes, but the steel belts in car tyres are nothing like that.

Imagine one bent round into a circle (like the internal structure of a
tyre). What would you get if it was made out of flexible materials at
the flat section at the bottom, where the thing spreads out?

I really can't think of any other way to make it any simpler for you?

Trouble is that it nothing like a real steel belt in a car tyre and is
encased in rubber too.

"Andy Burns" wrote in message
...
Jeff wrote:

"T i m" wrote:
But the two are interlinked?

Can't be by much given that you'd expect the axle to road distance to
have
dropped by more than 0.4%, although he didn't actually measure that.

I can drop the pressure back to 31 and measure the drop of the axle,

Yes please.

certainly it was visibly more than 0.4%, of course I won't be inside the
car adding weight while I measure it ...

Sounds like a relatively heavy vehicle given the 39 psi tyre pressure so
that
may not matter much.

"T i m" wrote in message
...
On Fri, 29 Jun 2018 07:35:45 +1000, "Jeff" wrote:

snip

They do in the sense that presumably the distance from the axle to the
road
dropped
by rather more than the 0.4% that the ABS sensors recorded, so the
effect
must
indeed be due to the circumference changing, not the dynamic rolling
radius.

But the two are interlinked?

Can't be by much given that you'd expect the axle to road distance to have
dropped by more than 0.4%, although he didn't actually measure that.

I didn't watch whatever you are referring to

Nothing to watch, I was referring to Andy's report of what he saw
reported by the ABS wheel sensors on the OBD2 system.

as it doesn't matter. I
don't need to because I know iTPMS does work and therefore the only
way it can work. ;-)

39psi is quite high so it may be a pretty big solid wheel and tyre, so
it would be interesting to have had that distance measured.

Possibly.

If you accept the circumference changes between the tyre carrying no
load, the tyre carrying load and inflated correctly and the tyre
running at a lower pressure, then in the first case there is a
conventional radius and in the last two, because the tyre is no longer
circular and because it shrinks under the footprint, we also have a
rolling radius.

What we can't say with any certainty is the actual distance between
the axle and the road is the same as the rolling radius (because by
definition the centre of the axle will be low of centre of the
effective circumference, simply because of how tyres work.

With iTPMS I believe some manufacturers shun (or shunned) it because
it is much more critical in it's calibration than the direct reading
TPMS.

A new tyre, tyre rotation, a managed change in pressure generally
require a 'reset' or the system could become unreliable. This is
considered 'too interactive by some manufacturers, having to rely on
human input to keep the system reliable.

But it should be possible to reset it automatically when it is clear
that a wheel has been changed, say because it had to be to pass the
MOT or the tyre pressure had been changed at the service station

Yup, possibly it could be automatic, especially if it could cross
reference the iTPMS with GPS etc.

This would confirm the concept of iTPMS working with very small
differences ... the sort you get when you change a tyre or get a
puncture. ;-)

A slow leak too.

Quite.

Tim Streater wrote:

It can change *shape* but not *length* (except by 1% or so, which no
one is disputing), and that is what I say above.

Now that we know that we're talking about detecting speed changes under
0.5% you can't discount a circumference change of 1%

On Fri, 29 Jun 2018 08:24:47 +0100, Tim Streater
wrote:

snip

Why the sudden change? Now TNP has claimed that the circumference can
change you also change to say it can.

It can change *shape* but not *length* (except by 1% or so, which no
one is disputing), and that is what I say above.

So it can't change it's length but can change it's length?

Typical Brexiteer.

Cheers, T i m

On Fri, 29 Jun 2018 10:00:30 +1000, "Jeff" wrote:



"T i m" wrote in message
.. .
On Fri, 29 Jun 2018 06:43:35 +1000, "Jeff" wrote:



"T i m" wrote in message
...

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either.

Then come up with a more credible one?

I prefer to measure, not speculate.

Come up with the measurements then?

the tyre 'spread more' as it gets flatter and why would the circumference
get shorter even if it did

What part of 'pantographing' don't you get OOI?

I've never been convinced by your pantograph line.

It's not mine, it's what those people who know know.

The steel belts arent panto graphs.

Ok. The belts are woven between the beads in a ziz-zag, working their
way round the tyre till they join up again. these cross at roughly 90
degrees and form a parallelogram. When you load a tyre that causes it
to widen, it has to get the material from somewhere and because the
rubber is 'bound' to some degree by the bets, the only way that can
happen is some foreshortening of the length of the tread from where
it's distorted.

What do you have as an alternative explanation?

Have you ever seen one of those expanding pop rivet guns ... of the
joke boxing glove on an expanding arm?

When those things get wider they get shorter.

Yes, but the steel belts in car tyres are nothing like that.

They are everything like that (but maybe you just don't realise it)?

Imagine one bent round into a circle (like the internal structure of a
tyre). What would you get if it was made out of flexible materials at
the flat section at the bottom, where the thing spreads out?

I really can't think of any other way to make it any simpler for you?

Trouble is that it nothing like a real steel belt in a car tyre and is
encased in rubber too.

You are Rod aren't you ... ;-(

Cheers, T i m

On Fri, 29 Jun 2018 08:22:25 +0100, Tim Streater
wrote:

In article , "dennis@home" wrote:

On 28/06/2018 21:43, Jeff wrote:


"T i m" wrote in message
...

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either. Why would
the tyre 'spread more' as it gets flatter and why would the circumference
get shorter even if it did

Well that is the obvious bit, less pressure means more of the tyre has
to be in contact with the road to take the load.

The circumference of a tyre is not a fixed length.

For the purposes of this discussion, it is.

It's exactly for the purpose of this discussion IT ISN'T!!

Brexiteers eh ... ;-(

Cheers, T i m

On Fri, 29 Jun 2018 08:26:56 +0100, Tim Streater
wrote:

snip

TNP says if they rotate at different rates the treads fall off..
I say treads do fall of.
You think it means I am agreeing with TNP.

You are.

Aww Bless. The poor goblin is so confused now ... glimmers of
understanding but can't_actually_say_it for fear of upsetting his
goblin master, the great Turnip. ;-)

Just think for a second instead of parroting TNP..
The tread changes length when it hits the road so that bit of the tyre
is rotating at a different rate to the rest so yes tyres do rotate at
different rates to the wheel some bits at one rate some at another and
some at all the values in between.

And over a revolution, the rate must be the same, else the tread would
come off.

Whoosh.

The rate of shrinkage of the tyre is fixed (it's not of course as the
load on the tyre is dynamic in use but that would be a step way too
far for the Streater goblin's tiny brain) for a good (non punctured)
tyre but the location of the shrinkage moves round the tyre. The bit
that is causing the tyre to shrink is the bit sat stationary on the
road so no damage to the tyre occurs.

So, you can have an effective circumference that is smaller than the
unloaded one that does not put the tread under any additional stress.

*That* is QED.

Cheers, T i m

On 29/06/2018 08:22, Tim Streater wrote:
In article , "dennis@home" wrote:

On 28/06/2018 21:43, Jeff wrote:


"T i m" wrote in message
...

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either. Why would
the tyre 'spread more' as it gets flatter and why would the
circumference
get shorter even if it did

Well that is the obvious bit, less pressure means more of the tyre has
to be in contact with the road to take the load.

The circumference of a tyre is not a fixed length.

For the purposes of this discussion, it is.


So that you can prove something that actually wors doesn't and for you
to win a false argument!
Then you claim to be using physics.
You must be a failed climate scientist who thinks proving the impossible
by changing the laws of physics is a good thing.

On 28/06/18 19:27, Jeff wrote:


"The Natural Philosopher" wrote in message
news
On 28/06/18 12:11, Jeff wrote:
What matters is the rotation rate of the wheel, because that
is what the ABS sensors are measuring.
No. In the context iof this thread it is utterly irrelvant.#

But we don't disagree that the rate changes. Only by how much, and why.

And when you measure how much the rate changes, that will
tell you if it is changing due to the change in circumference or
the change in the distance between the axle and the road because
one changes much more than the other with under pressure.

And others have indeed done this, and there is a videos showing it tghat
proves my point

But you dont need to do the experiment, correctly applied mecahanics
gives the correct naswer.



--
When plunder becomes a way of life for a group of men in a society, over
the course of time they create for themselves a legal system that
authorizes it and a moral code that glorifies it.

Frédéric Bastiat

On 28/06/18 21:24, Andy Burns wrote:
The Natural Philosopher wrote:

we don't disagree that the rate changes. Only by how much

As there was nothing on telly tonight, I used my OBD cable to log the
four wheel speed sensors over a straight section of road with cruise
control set to 50mph, which was measured by VCDS as 77.6kph then let
some pressure out of the right rear, turned around, rinse and repeat
until the TPMS triggered.

Starting at 39psi the right rear was on average 0.1kph slower than the
other three wheels, it triggered after letting it down to 31psi by which
time it was on average 0.2kph faster than the other three wheels.

So it triggered on a increased wheel speed of 0.3/77.6 = 0.4%

and why.

The numbers don't help with that.

Oh but they do.

now measure the distance between the axle and the road on te inflated
and deflateted side and tell me oif they are 0.4%
different or a far larger number.



--
When plunder becomes a way of life for a group of men in a society, over
the course of time they create for themselves a legal system that
authorizes it and a moral code that glorifies it.

Frédéric Bastiat

On 28/06/18 21:43, Jeff wrote:


"T i m" wrote in message
...

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either. Why would
the tyre 'spread more' as it gets flatter and why would the circumference
get shorter even if it did

A 27yr old girl gave the right answer instantly when the combined
brains of Turnip and his goblin Streater still cannot!

Bwhahahahahaha ... !!!


Just shows that a 27 year old gorl is completely unable to have a basic
comprehension of engineering anmd mechanical sciences just as much as
her benighted stupid dad.



--
"And if the blind lead the blind, both shall fall into the ditch".

Gospel of St. Mathew 15:14

On 29/06/2018 08:51, Andy Burns wrote:
Tim Streater wrote:

It can change *shape* but not *length* (except by 1% or so, which no
one is disputing), and that is what I say above.

Now that we know that we're talking about detecting speed changes under
0.5% you can't discount a circumference change of 1%

A flat will change by more than 0.5% as shown empirically by another poster.

Its also fairly obvious that it will from the destruction of one twin
wheel tyre on a lorry. If it only changed by say 1% the tyre wouldn't
generate enough heat to destroy it and its the heat that does it.

On single wheels the friction between the slower moving inner bit of the
tyre and the outer will generate plenty of heat and wear to destroy the
tyre.

The twin wheel one won't have this contact so the heat generated in
compressing and stretching the tread is what does it.

On 29/06/18 08:51, Andy Burns wrote:
Tim Streater wrote:

It can change *shape* but not *length* (except by 1% or so, which no
one is disputing), and that is what I say above.

Now that we know that we're talking about detecting speed changes under
0.5% you can't discount a circumference change of 1%.


We dont.

That sort of change is about what one would expect from steel or kevlar
cables.



--
Microsoft : the best reason to go to Linux that ever existed.

On 29/06/18 08:22, Tim Streater wrote:
In article , "dennis@home" wrote:

On 28/06/2018 21:43, Jeff wrote:


"T i m" wrote in message
...

Bingo.

I was walking round the park with our daughter earlier and I gave her
the nutshell iTPMS overview and asked her how she thought it might
work ... how the circumference could become shorter for the iTPMS to
'sense' the increased RPM.

"As the tyre gets flatter it spreads more and that makes the
circumference shorter and so the revs higher?"

Not convinced and that summary makes no sense either. Why would
the tyre 'spread more' as it gets flatter and why would the
circumference
get shorter even if it did

Well that is the obvious bit, less pressure means more of the tyre has
to be in contact with the road to take the load.

The circumference of a tyre is not a fixed length.

For the purposes of this discussion, it is.

It is far more fixed than the distance of te axle from the road....

--
The theory of Communism may be summed up in one sentence: Abolish all
private property.

Karl Marx

dennis@home wrote:

A flat will change by more than 0.5%

what aspect of it?

as shown empirically by another poster.

who, where? I might have missed it ...

The Natural Philosopher wrote:

Andy Burns wrote:

you can't discount a circumference change of 1%.

We dont.

That sort of change is about what one would expect from steel or kevlar
cables.

we seem to have some people saying
"it doesn't happen, but it does happen a bit"

others saying "it does happen but it's insignificant"

others saying "it happens and it's enough to be significant"

is there anyone left saying "it doesn't happen fullstop" ?

On 29/06/2018 08:26, Tim Streater wrote:
In article , "dennis@home" wrote:

On 28/06/2018 21:19, Tim Streater wrote:
In article , "dennis@home" wrote:

On 28/06/2018 16:40, Tim Streater wrote:
In article , "dennis@home" wrote:

On 28/06/2018 10:59, The Natural Philosopher wrote:

What I wouuld ask you is how a tyre, rotating at a differentent
rate from a wheel, so that its circumference does in fact get
covered on the ground by that rotaion, stays on the wheel without
ripping the tread off?

This "philosopher" hasn't ever noticed the tyre debris on the
roads where the tread has been ripped off.

Maybe he wants to explain why it happens to lorries with twin
wheels where only one tyre has gone flat but is being kept at
about the correct radius by the other wheel?

Ah, nice attempt at a shimmy there, Den. Our Dave would be proud of
you.

What you're in fact admitting is that the wheel and the tire *must*
rotate at the same rate, otherwise the tread would come off.


How dumb can you be to think that is what I said?
I said the exact opposite of what you chose to claim I said.

Are you TNP ?

TNP says (above) that having a wheel rotating at a different rate to
the tire is only possible if the tread rips off.

You point out how much tire debris there is around.

QED.

You are just hoping nobody bothers to think about what you claim.

TNP says if they rotate at different rates the treads fall off..
I say treads do fall of.
You think it means I amÂ* agreeing with TNP.

You are.

Just think for a second instead of parroting TNP..
The tread changes length when it hits the road so that bit of the tyre
is rotating at a different rate to the rest so yes tyres do rotate at
different rates to the wheel some bits at one rate some at another and
some at all the values in between.

And over a revolution, the rate must be the same, else the tread would
come off.


You are being obtuse to troll.
The above says the rate varies around the tyre, the average is one rev
of the tyre is one rev of the wheel. The distance covered will be the
average.
The average will change depending on the static load, the pressure and
the dynamic load.
The reason it changes is because the circumference changes when all
these forces are acting on it.

Now snip that to try and prove I said something else but remember
everyone else has already read it except for the idiots like TNP that
have killfiled me because they can't argue with someone that is correct.

You shouldn't listen to TNP, he claims to understand engineering and
physics but as you can see from this thread he is closed minded and will
fight his position long after it has been shown to be wrong, just like you.

You, TNP, and harry have that in common. I guess thats why you still
support brexit as you can't see the problems that it is producing and
will keep you "solutions" in your mind no matter how wrong they are
proven to be.

On Fri, 29 Jun 2018 09:46:12 +0100, Andy Burns
wrote:

The Natural Philosopher wrote:

Andy Burns wrote:

you can't discount a circumference change of 1%.

We dont.

That sort of change is about what one would expect from steel or kevlar
cables.

we seem to have some people saying
"it doesn't happen, but it does happen a bit"

others saying "it does happen but it's insignificant"

others saying "it happens and it's enough to be significant"

is there anyone left saying "it doesn't happen fullstop" ?

;-)

As I said, they will all get there in the end Andy ... they will have
to because:

1) It's obviously *the* answer

2) They don't have any alternative explanation

3) They will (therefore) have to to stand any chance of retaining any
credibility (even they get some stuff right sometimes). ;-)


Cheers, T i m

On Fri, 29 Jun 2018 09:25:38 +0100, "dennis@home"
wrote:

On 29/06/2018 08:22, Tim Streater wrote:
snip

For the purposes of this discussion, it is.


So that you can prove something that actually wors doesn't and for you
to win a false argument!

Sounds par for the course.

Then you claim to be using physics.

The actual names for it are 'guesswork' and 'hunches'. Same rules as
the used for Brexit of course.

You must be a failed climate scientist who thinks proving the impossible
by changing the laws of physics is a good thing.

No, he's a failed Media Studies student who had to then do Fine Arts.
;-)

What he isn't is an Engineer, that's for sure as some of the stuff
he's be coming out with are soooo bizarre easily demonstrate.

Cheers, T i m

On 29/06/18 09:46, Andy Burns wrote:
The Natural Philosopher wrote:

Andy Burns wrote:

you can't discount a circumference change of 1%.

We dont.

That sort of change is about what one would expect from steel or
kevlar cables.

we seem to have some people saying
"it doesn't happen, but it does happen a bit"

others saying "it does happen but it's insignificant"

others saying "it happens and it's enough to be significant"

is there anyone left saying "it doesn't happen fullstop" ?

Nope.

I say its insiginicant in terms of ordinary measurements. You beed veruy
careful speed monitoring to detecte it - a simple exoeriment wont.

My thesis has always been to try and illustrate the erroneous thinking
of those who think in terms of radius rather than circmference.

Because its an intersting engineering problem and has highlighted a very
intersteing psychological and educational issue.


--
"Women actually are capable of being far more than the feminists will
let them."