On Sat, 30 Jun 2018 06:48:18 +0100, Richard
wrote:

On 29/06/18 18:41, T i m wrote:
On Fri, 29 Jun 2018 13:57:07 +0200, Thomas Prufer
wrote:

On Fri, 29 Jun 2018 11:39:41 +0100, Andy Burns wrote:

Well, my axle is 5mm closer to the road (when stationary, who know how
much centrifugal [let's not have *that* discussion] force negates that
when moving?)

I'll inject facts into the handwaving fest:-)

I'm not sure it will make any difference Tomas as 'some people' don't
believe the facts, imperial evidence (millions of cars with iTPMS) and
the 'experts'.

empirical

Dicky, thank's for that (that's what I was intending to type but the
spell checker changed and the character size is pretty small on that
dialogue box, especially when my eyes are tired).

Do us a favour though, if you are only going to correct one word in a
post, snip all the stuff that follows that ... (the rest left in to
demonstrate the point).


They would prefer (if ever) to come to the exact same conclusion
themselves but shroud it very carefully in a desperate attempt to make
it look like they understood it all along and thinking they can hide
the *fact* they are indeed 'stupid and arrogant tw*ts'. ;-)

A diagonally belted tire has 5% more travel per rotation at 180km/h than at
60km/h, a radially belted tire 1% more.

So, that's because of the pantographing effect (like the dragster
drive wheel I linked to ages ago) as it is spun up, opposite to that
of a deflation (or course).

This from the German Wiki page on the subject "Abrollumfang".

The article also contains the words "the dynamic rolling radius under load is
greater than the distance from the wheel middle to the road r sub(s)." and a
formula I can't be arsed to transcribe, but I'll toss in

;-)

r sub(0): unloaded wheel radius
r sub(s): static radius
r sub(D): dynamic radius

The left brainers will 'get' the direct stuff but won't get the stuff
that requires some imagination.

https://de.wikipedia.org/wiki/Abrollumfang

Thanks for trying though. ;-)

Cheers, T i m


Cheers, T i m

On Sat, 30 Jun 2018 13:15:45 +1000, "Jeff" wrote:

snip

Watching TNP going from denying that the circumference changes

He actually said originally that it changes by less than 1% and it turns
out that he was correct about that

But he also said in his OP:

"Does a tyre change its CIRCUMFERENCE when under inflated?

Answer. not by very much, if at all.

This seems to be a perpetual urban myth."

'If at all' and *a perpetual urban myth* that is making millions of
iTPMS systems work every day (as he finally comes to accept)?

However, because he is a tortured mind, he went on to say:

"It tyre pressure sensors are using this, it has to be a very very
complicated bit of software to detect - say - less than 1% change in
RPM relative to the other wheels."

He then spent the rest of the thread denying the concept of terms like
'rolling radius' when it was patently obvious to everyone who
understood how a tyres 'effective circumference' was less than it's
unloaded one so there must also be a 'loaded radius' that went with
that. Except he's a left brainer so he can't grasp things he can't
actually measure with a rule (but could easily calculate).

Are you looking to become one of his pet goblins, like Streater?

and it is now clear that the distance
between the axle and the road changes by much more than that,

Doh ... who said it didn't? Stop press, if you reduce the pressure in
a loaded tyre, the distance between the axle and the road drops!!! Who
would have thought eh?

3 times
more in fact, at least with that particular car and those tyre pressures.

Quite ... you can't draw any real conclusion re the actual distance
till you know all the other factors (like tirewall stiffness, pressure
drop and overall load etc).

If Turnip accepted how and why iTPMS systems worked, why did he post a
question about it (and argue the accepted facts of many throughout
it)?

Cheers, T i m

On 30/06/2018 04:15, Jeff wrote:

He actually said originally that it changes by less than 1% and it turns
out that he was correct about that and it is now clear that the distance
between the axle and the road changes by much more than that, 3 times
more in fact, at least with that particular car and those tyre pressures.

There have been a lot of posts where he and his supporters have said it
doesn't change, some where they have defined it as not changing as
though they think it doesn't obey the laws of physics.

Also there hasn't been any proof that it changes by less than 1% on a
flat tyre. We do know that some TPMS can detect a very small change when
the pressure drops from 39 to about 31 on one car from measurements done.

"T i m" wrote in message
...
On Sat, 30 Jun 2018 13:15:45 +1000, "Jeff" wrote:

snip

Watching TNP going from denying that the circumference changes

He actually said originally that it changes by less than 1% and it turns
out that he was correct about that

But he also said in his OP:

"Does a tyre change its CIRCUMFERENCE when under inflated?

Answer. not by very much, if at all.

This seems to be a perpetual urban myth."

'If at all' and *a perpetual urban myth* that is making millions of
iTPMS systems work every day (as he finally comes to accept)?

However, because he is a tortured mind, he went on to say:

"It tyre pressure sensors are using this, it has to be a very very
complicated bit of software to detect - say - less than 1% change in
RPM relative to the other wheels."

He then spent the rest of the thread denying the concept of terms like
'rolling radius' when it was patently obvious to everyone who
understood how a tyres 'effective circumference' was less than it's
unloaded one so there must also be a 'loaded radius' that went with
that. Except he's a left brainer so he can't grasp things he can't
actually measure with a rule (but could easily calculate).

Are you looking to become one of his pet goblins, like Streater?

and it is now clear that the distance
between the axle and the road changes by much more than that,

Doh ... who said it didn't? Stop press, if you reduce the pressure in
a loaded tyre, the distance between the axle and the road drops!!! Who
would have thought eh?

3 times
more in fact, at least with that particular car and those tyre pressures.

Quite ... you can't draw any real conclusion re the actual distance
till you know all the other factors (like tirewall stiffness, pressure
drop and overall load etc).

If Turnip accepted how and why iTPMS systems worked, why did he post a
question about it

He didn't, someone else asked how it works.

(and argue the accepted facts of many throughout
it)?

He didn't do that either.

"dennis@home" wrote in message
...
On 30/06/2018 04:15, Jeff wrote:

He actually said originally that it changes by less than 1% and it turns
out that he was correct about that and it is now clear that the distance
between the axle and the road changes by much more than that, 3 times
more in fact, at least with that particular car and those tyre pressures.

There have been a lot of posts where he and his supporters have said it
doesn't change,

I dont believe he has ever said that.

some where they have defined it as not changing as
though they think it doesn't obey the laws of physics.

Also there hasn't been any proof that it changes by less than 1% on a flat
tyre.

That wasnt what the OP asked about.

We do know that some TPMS can detect a very small change when
the pressure drops from 39 to about 31 on one car from measurements done.

It is unlikely that iTMPS doesnt work on any car with inflatable tyres.

On Sat, 30 Jun 2018 05:07:57 +1000, cantankerous geezer Rot Speed blabbered,
again:

I haven't had a flat since but there is always the chance.

There is no spare on the latest car nor anywhere to put one

Which car is that ? Stupid idea IMO.

so the AA can fix it next time.

Trouble with that approach is the annual cost of that and the much
longer time for them to show up than to change it yourself.

You do know what he thinks of you, don't you, senile Rot? Yet you are so
miserable and lonely that you STILL need to talk to him! BG

--
dennis@home to know-it-all Rot Speed:
"You really should stop commenting on things you know nothing about."
Message-ID:

On Sat, 30 Jun 2018 05:11:02 +1000, cantankerous geezer Rot Speed blabbered,
again:

It might be but unless you can measure it under the dynamic conditions it
is just a guess.
I think it would be hard to get an accurate measurement while driving

Not really, shouldn¢t be hard to have a laser mounted
on an arm outside the car, from the roof rack

and a rolling road isn't going to help either.

Correct.

I don't suppose you have a laser you can exactly centre on the wheel and
suspend a measure down from the wheel arch with a slow mo camera to record
what actually happens? Not serious BTW.

It wouldn¢t be hard to do.

You haven't yet realized that all these good people here prefer to ignore
your pesky trolls, Rot? You just don't give up easily, especially as most
people in real life seem to ignore you too! BG

--
dennis@home to know-it-all Rot Speed:
"You really should stop commenting on things you know nothing about."
Message-ID:

On Sat, 30 Jun 2018 04:00:36 +1000, cantankerous geezer Rot Speed blabbered,
again:

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.

They just don¢t see

They ALL see what the matter is with you, Rot!

--
dennis@home to know-it-all Rot Speed:
"You really should stop commenting on things you know nothing about."
Message-ID:

YVW

On 30/06/2018 10:36, Tim Streater wrote:

TNP can speak for himself but I've always accepted that it may change
1% or so between inflated and flat. But that difference is not what is
being argued about, as I have said before.


I'm not arguing about anything. I just stated the obvious, that it does
change and why it changes.
I haven't got the computer model that would be needed to work out what
change you would get from a particular tyre/wheel/car/road combination
and at what speeds and what pressures.
It is far from a simple exercise to work it out.

On Sat, 30 Jun 2018 19:29:02 +1000, "Jeff" wrote:



"dennis@home" wrote in message
...
On 30/06/2018 04:15, Jeff wrote:

He actually said originally that it changes by less than 1% and it turns
out that he was correct about that and it is now clear that the distance
between the axle and the road changes by much more than that, 3 times
more in fact, at least with that particular car and those tyre pressures.

There have been a lot of posts where he and his supporters have said it
doesn't change,

I don’t believe he has ever said that.

Are you in denial or something? What part of:

Turnip: "Does a tyre change its CIRCUMFERENCE when under inflated?

Answer. not by very much, if at all.

This seems to be a perpetual urban myth."

.... don't you understand (that Turnip wrote)?

some where they have defined it as not changing as
though they think it doesn't obey the laws of physics.

Also there hasn't been any proof that it changes by less than 1% on a flat
tyre.

That wasn’t what the OP asked about.

Again, that was *exactly* what he was asking about:

Turnip: "It tyre pressure sensors are using this, it has to be a very
very complicated bit of software to detect - say - less than 1% change
in RPM relative to the other wheels.

(Ok, the fact that it starts with a typo where Turnips 'It' should
have been an 'If' but I'd hope even you could work that one out). ;-(


We do know that some TPMS can detect a very small change when
the pressure drops from 39 to about 31 on one car from measurements done.

Yes, *we* know that direct TPMS's can detect fairly small increments
in pressure change whereas we also know that iTPMs systems can't. This
is why several car manufacturers don't use iTPMS.

It is unlikely that iTMPS doesn’t work on any car with inflatable tyres.

True, however iTPMS systems do need more driver intervention re
resetting (another reason why they are / were shunned by some
manufacturers) and rely on the vehicle having wheel rotation sensors
installed.

Cheers, T i m

On 30/06/2018 11:56, Tim Streater wrote:
In article , "dennis@home" wrote:

On 30/06/2018 10:36, Tim Streater wrote:

TNP can speak for himself but I've always accepted that it may change
1% or so between inflated and flat. But that difference is not what is
being argued about, as I have said before.


I'm not arguing about anything. I just stated the obvious, that it
does change and why it changes.

No it doesn't (apart from the 1%). And you haven't presented any
evidence or arguments to the contrary.


If you say so.
However what you say is not true, but IME it seldom is.

"dennis@home" wrote in message
...
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.

It isnt heat that sees the entire tread come off on a twin wheel tyre,
that is due to the retread coming off.

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.

"Andy Burns" wrote in message
...
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?

The inner one usually just has a much longer filler pipe so it can be
pumped up from outside the outer wheel, and that is from a mate of mine
that drives them for a living and you can check that by looking at them.

Jeff wrote:

Andy Burns wrote

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

The inner one usually just has a much longer filler pipe so it can be
pumped up from outside the outer wheel

That's the pipe I'd seen and assumed linked them ... seems you /can/ get
kits to link them, but that's not the norm.

On 01/07/2018 07:01, Jeff wrote:


"dennis@home" wrote in message
...
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.

It isnt heat that sees the entire tread come off on a twin wheel tyre,
that is due to the retread coming off.

Well why do you think it comes off?
Anyway quite often its the entire carcass too.

If you have driven million miles on motorways you tend to see a lot of
this stuff.

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

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

The inner one usually just has a much longer filler pipe so it can be
pumped up from outside the outer wheel

That's the pipe I'd seen and assumed linked them ... seems you /can/ get
kits to link them, but that's not the norm.

Yeah, you can have central electric systems that allow you to change
the pressure in all of them at once too, but again, not the norm.

"dennis@home" wrote in message
...
On 01/07/2018 07:01, Jeff wrote:


"dennis@home" wrote in message
...
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.

It isnt heat that sees the entire tread come off on a twin wheel tyre,
that is due to the retread coming off.

Well why do you think it comes off?

Because trucks still use retreads.

Anyway quite often its the entire carcass too.

Hardly ever.

If you have driven million miles on motorways you tend to see a lot of
this stuff.

Hardly ever the entire carcass.

On 01/07/2018 07:01, Jeff wrote:


"dennis@home" wrote in message
...
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.

It isnt heat that sees the entire tread come off on a twin wheel tyre,
that is due to the retread coming off.

Then some clown reports that they have seen a crocodile on the motorway.

--
Max Demian

On Sun, 1 Jul 2018 08:43:32 +0100, Andy Burns
wrote:

Jeff wrote:

Andy Burns wrote

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

The inner one usually just has a much longer filler pipe so it can be
pumped up from outside the outer wheel


That's the pipe I'd seen and assumed linked them ... seems you /can/ get
kits to link them, but that's not the norm.

As confirmed by my mate the HGV driver transport manager and
another (current) HGV driver. ;-)

A mate did a physical experiment with one of his spare tyres.

He pumped the tyre (Pirelli P6000 195/65 15) up to 50 PSI and ran some
galvanised steel wire around the central groove and twisted the ends
together till he could still feel a tiny amount of slack. Then he let
the tyre down to 10 PSI and noted that the slack had increased
significantly.

Now, whilst that confirms a tyre will 'expand' (or change profile)
under pressure, it doesn't go any way to confirming (or demonstrating
as we would see it) that the effective circumference is reduced at the
cord created by the distortion of the tyre under load.

Cheers, T i m