Tire pressure sensors?

Hi all,

A friend has a '08 A4 Avant (U.S. spec), and we were wondering if
anyone knows how reliable and accurate the tire pressure sensors are.
Are they good enough to rely on to know that your tires are soft? Or
is a good tire gauge and a weekly/monthly check still the best route?

Thanks.
--

"Paul Dhuse" > wrote in message
news:t1kSDs33RET1-pn2-6Y1V5DEVQCWo@localhost...
> Hi all,
>
> A friend has a '08 A4 Avant (U.S. spec), and we were wondering if
> anyone knows how reliable and accurate the tire pressure sensors are.
> Are they good enough to rely on to know that your tires are soft? Or
> is a good tire gauge and a weekly/monthly check still the best route?
>
> Thanks.
> --
>
>

To register pressure they must come through a slip ring on each hub, so its
how good are the seals and how long will they last. This technology is a by
product of motor racing, where the cars are stripped down and rebuilt after
every race...........so how long will it last in a car that does not see
that treatment. The monthly check is easy and you can then compare figures.
Why not let one tyre down and compare the electronic reading to your manual
gauge.

On Sat, 4 Apr 2009 06:56:34 +0100, "Tom E" > wrote:

>
>"Paul Dhuse" > wrote in message
>news:t1kSDs33RET1-pn2-6Y1V5DEVQCWo@localhost...
>> Hi all,
>>
>> A friend has a '08 A4 Avant (U.S. spec), and we were wondering if
>> anyone knows how reliable and accurate the tire pressure sensors are.
>> Are they good enough to rely on to know that your tires are soft? Or
>> is a good tire gauge and a weekly/monthly check still the best route?
>>
>> Thanks.
>> --
>>
>>
>
>To register pressure they must come through a slip ring on each hub, so its
>how good are the seals and how long will they last. This technology is a by
>product of motor racing, where the cars are stripped down and rebuilt after
>every race...........so how long will it last in a car that does not see
>that treatment. The monthly check is easy and you can then compare figures.
>Why not let one tyre down and compare the electronic reading to your manual
>gauge.

Which manufacturers use "slip rings" to convey TPM data? That's the first I've
heard of that, as to this point the systems I've read about used on consumer
vehicles either use RF with direct TPM sensors on the tire valve stems, or use
the same axle rotation sensors used for electronic stability controls and
antilock braking controls to indirectly derive inflation status. And those
sensors do not utilize "slip rings"...

"daytripper" > wrote in message
...
> On Sat, 4 Apr 2009 06:56:34 +0100, "Tom E" > wrote:
>
>>
>>"Paul Dhuse" > wrote in message
>>news:t1kSDs33RET1-pn2-6Y1V5DEVQCWo@localhost...
>>> Hi all,
>>>
>>> A friend has a '08 A4 Avant (U.S. spec), and we were wondering if
>>> anyone knows how reliable and accurate the tire pressure sensors are.
>>> Are they good enough to rely on to know that your tires are soft? Or
>>> is a good tire gauge and a weekly/monthly check still the best route?
>>>
>>> Thanks.
>>> --
>>>
>>>
>>
>>To register pressure they must come through a slip ring on each hub, so
>>its
>>how good are the seals and how long will they last. This technology is a
>>by
>>product of motor racing, where the cars are stripped down and rebuilt
>>after
>>every race...........so how long will it last in a car that does not see
>>that treatment. The monthly check is easy and you can then compare
>>figures.
>>Why not let one tyre down and compare the electronic reading to your
>>manual
>>gauge.
>
> Which manufacturers use "slip rings" to convey TPM data? That's the first
> I've
> heard of that, as to this point the systems I've read about used on
> consumer
> vehicles either use RF with direct TPM sensors on the tire valve stems, or
> use
> the same axle rotation sensors used for electronic stability controls and
> antilock braking controls to indirectly derive inflation status. And those
> sensors do not utilize "slip rings"...
>

my Uncles Fordson tractor................

On Sat, 4 Apr 2009 16:48:20 +0100, "Tom E" > wrote:
>
>"daytripper" > wrote in message
.. .
>> On Sat, 4 Apr 2009 06:56:34 +0100, "Tom E" > wrote:
>>
>>>"Paul Dhuse" > wrote in message
>>>news:t1kSDs33RET1-pn2-6Y1V5DEVQCWo@localhost...
>>>> Hi all,
>>>>
>>>> A friend has a '08 A4 Avant (U.S. spec), and we were wondering if
>>>> anyone knows how reliable and accurate the tire pressure sensors are.
>>>> Are they good enough to rely on to know that your tires are soft? Or
>>>> is a good tire gauge and a weekly/monthly check still the best route?
>>>>
>>>> Thanks.
>>>
>>>To register pressure they must come through a slip ring on each hub, so
>>>its how good are the seals and how long will they last. This technology is a
>>>by product of motor racing, where the cars are stripped down and rebuilt
>>>after every race...........so how long will it last in a car that does not see
>>>that treatment. The monthly check is easy and you can then compare
>>>figures.
>>>Why not let one tyre down and compare the electronic reading to your
>>>manual gauge.
>>
>> Which manufacturers use "slip rings" to convey TPM data? That's the first
>> I've heard of that, as to this point the systems I've read about used on
>> consumer vehicles either use RF with direct TPM sensors on the tire valve stems, or
>> use the same axle rotation sensors used for electronic stability controls and
>> antilock braking controls to indirectly derive inflation status. And those
>> sensors do not utilize "slip rings"...
>>
>
>my Uncles Fordson tractor................
>

Um, ok. I rather doubt a 40 to 90 year old farm tractor is relevant to the
question, but it certainly explains your answer ;-)