Tire Pressue Monitoring System.......
 

Who has installed a tire pressure monitoring system on their Pcar? There are a number of different systems on the market. Some use sensors strapped to the center of the wheel, some use sensors built into the valve stems and some simply replace the valve stem cap with a special sensor cap. The monitor mounts on or under the dash. The technology has gotten pretty refined over the last couple of years and is likely to be required on new cars soon.

I'd personally shy away from the valve stem cap type. Too prone to theft, leakage, etc.

A unit like this http://www.amazon.com/Hella-Pressure-Monitoring-Adjustable-Background/dp/B000QSDZQC

seems pretty nice....

I used the (now very old) Johnson Controls ones, which were valve stem type, on my street & track SHOs. The TPMS control was a replacement rearview mirror, which was very slick - warnings at low & no pressure, ability to cycle through the corners, and it really didn't throw the balance off on the wheels that much (nothing that couldn't easily be countered anyway).

What I didn't like about it was the stem didn't come out QUITE as far as I would have liked. The JC version never really made it to marketing, a buddy of mine worked for an engineering test company & had a bunch that sort of, uh, fell off a truck. :)

http://www.sae.org/automag/topprod/12-2002/index.htm

Nicest thing was quick & easy swaps of tires at the track - a couple of button presses on the unit, a magnet on each valve stem, & that set was ready to go. It was pretty accurate too, so that I didn't need to check pressures externally in the paddock after a session.


EDIT: The sensors are nearly identical to the Hella link in the post above mine, FWIW.

a tpms came standard on my cayman. while the absolute values may not be quite accurate (since it guesses what atmospheric pressure is) it is quite useful to monitor pressure rise during "spirited" driving.

Has anyone used these?

Analog:
[img]http://www.************//assets/product_images/prod/kw44444.jpg[/img]
Tirecheck Valve Stem Caps See at a glance when your tires need air! Just like a stoplight, when the indicator ...

or Battery Powered:
http://img.photobucket.com/albums/v5.../TireGuage.jpg
TireCheck - Flashing LED Tire Pressure Sensor
Flashes when tire pressure is too low! It’s hard to miss this warning device that starts

The problem with the valve stem caps is they introduce another point of failure into the tire/wheel assembly. They rely on releasing the pressure at the valve stem into a measuring device that monitors the tire pressure. I have tried various brands, and I have always experienced a failure.

In lieu of something more reliable, I'll stick to checking my pressure manually.