I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the tyre that communicates wirelessly with the car's systems?

Murmansk wrote:

I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the
tyre that communicates wirelessly with the car's systems?

That's one type, a battery, sensor and transmitter in a lump inside the
tyre, e.g.

https://www.eurofrance.pl/userdata/gfx/0f53520cb6b93802b9dd618dcafedc1b.jpg

The other type have no actual pressure sensor at all, but monitor the
relative speeds of the wheels from the ABS sensors, and spot slow (or
rapid) deflation based on that.

Tim Streater wrote:

Last winter on a couple of frosty mornings the pressure sensor came on,
went off later in the day. I wondered what it was at first.

I've had about a dozen warnings from TMPS (the ABS type) over the last
7+ years, not one of them false.

On 21/06/2018 21:51, Andy Burns wrote:
Tim Streater wrote:

Last winter on a couple of frosty mornings the pressure sensor came on,
went off later in the day. I wondered what it was at first.

I've had about a dozen warnings from TMPS (the ABS type) over the last
7+ years, not one of them false.

How flat were the tyres? How much pressure had they lost? 12 flat tyres
in 7+ years is much more than I would expect.


--
Michael Chare

On Sat, 23 Jun 2018 00:54:54 +0100, Michael Chare wrote:

On 21/06/2018 21:51, Andy Burns wrote:
Tim Streater wrote:

Last winter on a couple of frosty mornings the pressure sensor came
on,
went off later in the day. I wondered what it was at first.

I've had about a dozen warnings from TMPS (the ABS type) over the last
7+ years, not one of them false.

How flat were the tyres? How much pressure had they lost? 12 flat tyres
in 7+ years is much more than I would expect.

I had a spate of flattening tyres a few years ago. Turned out to be
peeling varnish on the allow wheels, spoiling the seal.

--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

On 23/06/2018 01:03, Bob Eager wrote:
On Sat, 23 Jun 2018 00:54:54 +0100, Michael Chare wrote:

On 21/06/2018 21:51, Andy Burns wrote:
Tim Streater wrote:

Last winter on a couple of frosty mornings the pressure sensor came
on,
went off later in the day. I wondered what it was at first.

I've had about a dozen warnings from TMPS (the ABS type) over the last
7+ years, not one of them false.

How flat were the tyres? How much pressure had they lost? 12 flat tyres
in 7+ years is much more than I would expect.

I had a spate of flattening tyres a few years ago. Turned out to be
peeling varnish on the allow wheels, spoiling the seal.


I do wonder about the benefits of alloy wheels. There was a recent
thread about the tyres on them sometimes not staying inflated and they
are quite easy to damage.

--
Michael Chare

"Michael Chare" wrote in message
news
On 21/06/2018 21:51, Andy Burns wrote:
Tim Streater wrote:

Last winter on a couple of frosty mornings the pressure sensor came on,
went off later in the day. I wondered what it was at first.

I've had about a dozen warnings from TMPS (the ABS type) over the last 7+
years, not one of them false.

How flat were the tyres? How much pressure had they lost? 12 flat tyres
in 7+ years is much more than I would expect.

Doesnt need to be flat, just under inflated. I've had lots of
those where when checking the tyre pressure at the service
station does see some more air needed in a particular tyre.

And my Getz is a real bugger with a true flat tyre, very hard
to even notice its gone flat and that means most of the flats
result in a buggered tyre since you drive on it flat long
enough to **** the tyre so that fixing the leak wont work.

On Sat, 23 Jun 2018 13:45:57 +1000, cantankerous geezer Rot Speed blabbered,
again:

result in a buggered tyre since you drive on it flat long
enough to **** the tyre so that fixing the leak wont work.

Who/what drove YOU long enough that you became completely ****ed, you
self-opinionated bigmouthed asshole? Or were you born that way?

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

Michael Chare wrote:

Andy Burns wrote:

I've had about a dozen warnings from TMPS (the ABS type) over the last
7+ years, not one of them false.

How flat were the tyres? How much pressure had they lost?

Varied ...

Several (yellow warning) times when tyres had just gradually lost
pressure without a puncture, maybe 43 down to 38psi, which would be
detected at about the same level as when I started to notice going over
speed humps was a bit softer than usual.

Several normal slow punctures from nails/screws (also yellow warning)

Once (red warning) where it picked up a fast puncture on the motorway
before I had noticed it, and by the time I had come to rest on the hard
shoulder the tyre was completely flat.

12 flat tyres in 7+ years is much more than I would expect.

Overall I think 5 were punctures (all except one were repairable) two
were from kerbs, the rest were just reminders to top-up pressures.

Several of the punctures occurred in the first year of buying the car, I
was half convinced there were nail-magnets fitted.

On 23/06/2018 06:38, Andy Burns wrote:
Michael Chare wrote:

Andy Burns wrote:

I've had about a dozen warnings from TMPS (the ABS type) over the
last 7+ years, not one of them false.

How flat were the tyres? How much pressure had they lost?

Varied ...

Several (yellow warning) times when tyres had just gradually lost
pressure without a puncture, maybe 43 down to 38psi, which would be
detected at about the same level as when I started to notice going over
speed humps was a bit softer than usual.

Several normal slow punctures from nails/screws (also yellow warning)

Once (red warning) where it picked up a fast puncture on the motorway
before I had noticed it, and by the time I had come to rest on the hard
shoulder the tyre was completely flat.

12 flat tyres in 7+ years is much more than I would expect.

Overall I think 5 were punctures (all except one were repairable) two
were from kerbs, the rest were just reminders to top-up pressures.

Several of the punctures occurred in the first year of buying the car, I
was half convinced there were nail-magnets fitted.

I thought I was prone to getting punctures but not as bad as that. I had
one wheel which vibrated a bit so I fitted it to the rear. Even then I
noticed a vibration at about 75mph. Eventually I had to stop for a flat
tyre and found that the tyre had developed a bulge say a couple of
inches in diameter which had then worn completely through. I wonder if
the pressure sensors in the tyres of my new car would have noticed that
before the tyre became completely flat.

--
Michael Chare

On 21/06/2018 20:54, Murmansk wrote:
I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the tyre that communicates wirelessly with the car's systems?


On mine I believe it uses the ABS sensors to determine if one wheel
(presumably over a period of time) is rotating faster than the others. A
deflated tyre will be smaller in circumference.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 21/06/18 21:02, alan_m wrote:
On 21/06/2018 20:54, Murmansk wrote:
I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the
tyre that communicates wirelessly with the car's systems?


On mine I believe it uses the ABS sensors to determine if one wheel
(presumably over a period of time) is rotating faster than the others. A
deflated tyre will be smaller in circumference.

Radius perhaps, but circumference - not much. The steel belts in the
tread take care of that.


--
€œA leader is best When people barely know he exists. Of a good leader,
who talks little,When his work is done, his aim fulfilled,They will say,
€œWe did this ourselves.€�

ۥ Lao Tzu, Tao Te Ching

alan_m wrote:
On 21/06/2018 20:54, Murmansk wrote:
I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the tyre
that communicates wirelessly with the car's systems?


On mine I believe it uses the ABS sensors to determine if one wheel
(presumably over a period of time) is rotating faster than the others. A
deflated tyre will be smaller in circumference.

Does it *really* work like that? Tyres have steel or nylon bracing in
them to *stop* them stretching much. If you run on a flat tyre it
squishes somewhat but, unless it's actually skidding on the road
surface, the same circumferance will roll along the road surface for
each rotation.

The difference in revs/metre between a tyre at (say) 2.5bar and one at
(say) 2.2bar must be really tiny.

Our tyre pressure warning goes off immediately you turn the ignition
on whichsuggest to me some sort of pressure sensor in the rim or
valve.

--
Chris Green
·

On 22/06/18 20:40, Chris Green wrote:
alan_m wrote:
On 21/06/2018 20:54, Murmansk wrote:
I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the tyre
that communicates wirelessly with the car's systems?


On mine I believe it uses the ABS sensors to determine if one wheel
(presumably over a period of time) is rotating faster than the others. A
deflated tyre will be smaller in circumference.

Does it *really* work like that? Tyres have steel or nylon bracing in
them to *stop* them stretching much. If you run on a flat tyre it
squishes somewhat but, unless it's actually skidding on the road
surface, the same circumferance will roll along the road surface for
each rotation.

The difference in revs/metre between a tyre at (say) 2.5bar and one at
(say) 2.2bar must be really tiny.

Our tyre pressure warning goes off immediately you turn the ignition
on whichsuggest to me some sort of pressure sensor in the rim or
valve.


I've had the light come on on the missus' Mini so it does work.

Chris Green wrote:

alan_m wrote:

uses the ABS sensors to determine if one wheel
(presumably over a period of time) is rotating faster than the others.

Does it *really* work like that?

Some absolutely do work that way, search "indirect TPMS"

Our tyre pressure warning goes off immediately you turn the ignition
on whichsuggest to me some sort of pressure sensor in the rim or
valve.

Sounds like yours is the "direct TPMS" type with pressure sensors.

On 22/06/2018 20:40, Chris Green wrote:
Does it*really* work like that? Tyres have steel or nylon bracing in
them to*stop* them stretching much. If you run on a flat tyre it
squishes somewhat but, unless it's actually skidding on the road
surface, the same circumferance will roll along the road surface for
each rotation.

Some of that circumference must rotate while it's off the ground.

The _radius_ at the bit on the ground is reduced, so it must spin the
tyre faster.

Andy

Vir Campestris wrote:

The _radius_ at the bit on the ground is reduced, so it must spin the
tyre faster.

Apparently 2nd generation indirect TPMS can use spectrum analysis
instead of simple rotation speed

https://niradynamics.se/products/tpi

On 22/06/18 22:01, Vir Campestris wrote:
On 22/06/2018 20:40, Chris Green wrote:
Does it*really*Â* work like that?Â* Tyres have steel or nylon bracing in
them to*stop*Â* them stretching much.Â* If you run on a flat tyre it
squishes somewhat but, unless it's actually skidding on the road
surface, the same circumferance will roll along the road surface for
each rotation.

Some of that circumference must rotate while it's off the ground.

The _radius_ at the bit on the ground is reduced, so it must spin the
tyre faster.


It would if a flat tyre was circular.

Since it isn't, you are talking relative ********

What is the radius of a tank track?


Andy


--
"A point of view can be a dangerous luxury when substituted for insight
and understanding".

Marshall McLuhan

On Sat, 23 Jun 2018 06:26:27 +0100, The Natural Philosopher
wrote:

snip

Since it isn't, you are talking relative ********

What is the radius of a tank track?

Just how distortable is a tank track, how many ply is it?

Do the lay of the plies form a mobile parallelogram allowing the
tracks themselves to change size under different circumstances
(including load bearing rotation)?

Cheers, T i m

On 23/06/2018 06:26, The Natural Philosopher wrote:
On 22/06/18 22:01, Vir Campestris wrote:
On 22/06/2018 20:40, Chris Green wrote:
Does it*really*Â* work like that?Â* Tyres have steel or nylon bracing in
them to*stop*Â* them stretching much.Â* If you run on a flat tyre it
squishes somewhat but, unless it's actually skidding on the road
surface, the same circumferance will roll along the road surface for
each rotation.

Some of that circumference must rotate while it's off the ground.

The _radius_ at the bit on the ground is reduced, so it must spin the
tyre faster.


It would if a flat tyre was circular.

Since it isn't, you are talking relative ********

What is the radius of a tank track?


I'll take this slowly, but only once.

Imagine a wheel that was flat at the bottom so that it had half its
original radius. The rolling radius of the wheel is the radius where it
touches the ground - half the normal radius.

This bit at the bottom is the only bit that counts. The rest is not on
the road.

A tank track doesn't have a radius. It isn't a circle. The effective
rolling radius of tank wheels is exactly the same as it would be if the
track wasn't there - it's just they are rolling along a track, not the
road. This is why it is called a track laying vehicle.

Andy

On Fri, 22 Jun 2018 20:40:22 +0100, Chris Green wrote:

snip

On mine I believe it uses the ABS sensors to determine if one wheel
(presumably over a period of time) is rotating faster than the others. A
deflated tyre will be smaller in circumference.

Does it *really* work like that? Tyres have steel or nylon bracing in
them to *stop* them stretching much. If you run on a flat tyre it
squishes somewhat but, unless it's actually skidding on the road
surface, the same circumferance will roll along the road surface for
each rotation.

It's not the circumference that determines the rotational speed but
the 'rolling radius. If you had a solid wheel (nearer to a cart or
train wheel) then the two would be pretty close but there would still
be some slight compression (in the spokes / rim / tyre of a cart wheel
and in the 'tyre' on a train wheel).

If you imagine the diameter of the tyre getting smaller as the tyre is
getting compressed at the bottom then the effective circumference
would change accordingly.

The difference in revs/metre between a tyre at (say) 2.5bar and one at
(say) 2.2bar must be really tiny.

Yes, it probably is, but it might still be enough to be 'sensed'
compared with the other wheel(s).

Our tyre pressure warning goes off immediately you turn the ignition
on whichsuggest to me some sort of pressure sensor in the rim or
valve.

That sounds most likely.

I believe the most common is a unit that is part of the valve that
contains a pressure sensor, battery and wireless transmitter and I
don't think you can replace the battery.

I always wondered why it couldn't have a rechargeable battery with
some sort of inertial charger but I guess that would make it too heavy
/ complicated.

Cheers, T i m

"Chris Green" wrote in message
...
alan_m wrote:
On 21/06/2018 20:54, Murmansk wrote:
I understand some new cars can tell you when their tyres need
inflating?

How do they work? Is there some kind of pressure sensor inside the tyre
that communicates wirelessly with the car's systems?


On mine I believe it uses the ABS sensors to determine if one wheel
(presumably over a period of time) is rotating faster than the others. A
deflated tyre will be smaller in circumference.

Does it *really* work like that? Tyres have steel or nylon bracing in
them to *stop* them stretching much. If you run on a flat tyre it
squishes somewhat but, unless it's actually skidding on the road
surface, the same circumferance will roll along the road surface for
each rotation.

The difference in revs/metre between a tyre at (say) 2.5bar and one at
(say) 2.2bar must be really tiny.

But the radius of the tyre at the position where it
contacts the road does change much more than that.

Our tyre pressure warning goes off immediately you turn the ignition
on whichsuggest to me some sort of pressure sensor in the rim or valve.

On Sat, 23 Jun 2018 13:10:16 +1000, cantankerous geezer Rot Speed blabbered,
again:


Does it *really* work like that? Tyres have steel or nylon bracing in
them to *stop* them stretching much. If you run on a flat tyre it
squishes somewhat but, unless it's actually skidding on the road
surface, the same circumferance will roll along the road surface for
each rotation.

The difference in revs/metre between a tyre at (say) 2.5bar and one at
(say) 2.2bar must be really tiny.

But the radius of the tyre at the position where it
contacts the road does change much more than that.

AGAIN: that was already mentioned, so what makes you believe that everyone
was waiting for your confirmation again, you self-opinionated senile
asshole?

--
Richard addressing Rot Speed:
"**** you're thick/pathetic excuse for a troll."
MID:

On 21/06/2018 20:54, Murmansk wrote:
I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the tyre that communicates wirelessly with the car's systems?


You could actually use google, you know ...

Anyway, there are two systems AFAIK. (I'd know more if I'd googled it,
but if you couldn't be bothered ...)

System 1: Uses a pressure sensor.

System 2: Senses if one of the wheels is going round more often than the
others = that wheel is flatter than the others. But if they are all
going flat together, that doesn't work. Also, you'll get a false reading
if you keep doing left turns and never turning right, like on the Indie 500.

GB wrote:
On 21/06/2018 20:54, Murmansk wrote:
I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the
tyre that communicates wirelessly with the car's systems?


You could actually use google, you know ...

Anyway, there are two systems AFAIK. (I'd know more if I'd googled it,
but if you couldn't be bothered ...)

System 1: Uses a pressure sensor.

System 2: Senses if one of the wheels is going round more often than the
others = that wheel is flatter than the others. But if they are all
going flat together, that doesn't work. Also, you'll get a false reading
if you keep doing left turns and never turning right, like on the Indie
500.



Some use bluetooth from sensors associated or near the filler nipple

Murmansk wrote

I understand some new cars can tell you when their tyres need inflating?

Yep.

How do they work? Is there some kind of pressure sensor inside
the tyre that communicates wirelessly with the car's systems?

In the wheel, yep.

On Fri, 22 Jun 2018 07:04:42 +1000, cantankerous geezer Rot Speed blabbered,
again:

I understand some new cars can tell you when their tyres need inflating?

Yep.

How do they work? Is there some kind of pressure sensor inside
the tyre that communicates wirelessly with the car's systems?

In the wheel, yep.

His questions were already answered, Rot. So why did you feel everyone was
waiting for your confirmation, you braindamaged senile cretin?

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

I don't think its wireless.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Murmansk" wrote in message
...
I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the tyre
that communicates wirelessly with the car's systems?

Brian Gaff wrote

I don't think its wireless.

It is with some of them.

Murmansk wrote

I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the tyre
that communicates wirelessly with the car's systems?

Rod Speed wrote:
Brian Gaff wrote

I don't think its wireless.

It is with some of them.

If it's not wireless what could it possibly be? ESP?

--
Chris Green
·

On 22/06/18 20:41, Chris Green wrote:
Rod Speed wrote:
Brian Gaff wrote

I don't think its wireless.

It is with some of them.

If it's not wireless what could it possibly be? ESP?


Tyre rotation based usually via the ABS sensors. Not really "pressure"
but more "your tyre's completely shagged".

On 22/06/2018 21:01, Tim Watts wrote:
On 22/06/18 20:41, Chris Green wrote:
Rod Speed wrote:
Brian Gaff wrote

I don't think its wireless.

It is with some of them.

If it's not wireless what could it possibly be?Â* ESP?


Tyre rotation based usually via the ABS sensors. Not really "pressure"
but more "your tyre's completely shagged".

That's the most basic version.

The "better" versions use low-powered, battery transmitters. Which of
course can fail; be wrecked by a flat; be wrecked by emergency sealant,
etc. One not working will now be an MOT failure, so that'll be a nice
little earner for the dealers.

SteveW

"Chris Green" wrote in message
...
Rod Speed wrote:
Brian Gaff wrote

I don't think its wireless.

It is with some of them.

If it's not wireless what could it possibly be? ESP?

In theory it could be done with slip rings
but in practice that isnt feasible in real life.

On 21/06/18 20:54, Murmansk wrote:
I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the tyre that communicates wirelessly with the car's systems?


2 ways:

1) Relative rotation - very hit and miss and tells you if one's heading
towards being a flatty but not much more;

2) There is a pressure sensor built into the valve in each tyre - long
life battery and radio transmission to one or more receivers.

On 22/06/2018 08:15, Tim Watts wrote:
On 21/06/18 20:54, Murmansk wrote:
I understand some new cars can tell you when their tyres need inflating?

How do they work? Is there some kind of pressure sensor inside the
tyre that communicates wirelessly with the car's systems?


2 ways:

1) Relative rotation - very hit and miss and tells you if one's heading
towards being a flatty but not much more;

2) There is a pressure sensor built into the valve in each tyre - long
life battery and radio transmission to one or more receivers.

I assume that the tyre pressure check in the new MOT is actually
checking that the system is not reporting an error because, say, the
battery in the sensor has gone flat.

--
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