Sresites

I have a spare set of Carrera Classic wheels I've decided to use for track events. Those of you that have a track set, do you have tire pressure sensors in use. I was going to have the TPSs installed at the dealer. But with mounting my spare 295s on the rears with new TPSs, paired and balanced came to $280 per wheel. Ouch. Thoughts.

The Fat Kid

Use the IM feature on Tire Rack and provide the make, model, and year of your car. They will provide a link to the correct HUF/Beru sensors. I think I paid ~$74/sensor (no tax/shipping), which was the best deal I found.

You should be looking at no more than $125/wheel all-in cost, even with Hunter Road Force balancing and TPMS installation.

991carreradriver

Others may disagree, but I have TPMS on my dedicated track wheels. I find it is very comforting to know when my tires are heating up and can be pushed (MSPC2's). I figure a failing tire due to heat can kill me, a failed engine won't. In fact, I set the PCM to monitor tire pressures during the entire track session. I use the Cobb Accessport to monitor all other functions, such as engine oil temp, fuel pressure, etc..

BradB

This is exactly what I do, too.

Vise

100% agreed, I do the same and tire pressures (ie. temps) are obviously super important when tracking a car.

In terms of the cost, $280 per wheel is absolute robbery. For my Forgelines I ordered the Huf Intellisens from TPMS.com... roughly $60 each and for an extra $5 I got to spec it with gunmetal valve stems. Works flawlessly too of course.

Looks like they are even cheaper now, just put in your year/model on the site...

http://www.tpms.com/2015_Porsche_911...PMS_s/6773.htm

Loud223

Funny I just bought a set of carrera S wheels yesterday for the track and was wondering the same thing about the tpms. I check the pressure after each session with a gauge but monitor tp during the session so I'll be installing the tpms on the track wheels.

Verboden

I'll be the odd one out, I don't run the sensors. I am not disputing all the points raised, just never felt the benefit was worth it.

I check pressure after every session, at least for the first few runs I am adjusting the pressure so knowing from inside the car that I will need to bleed is a moot point.

I'm gonna believe that if a tire has a fast enough leak to be an issue on the track I will begin to feel it and be able to come in. If its catastrophic then I'm not sure the sensor will warn me in time because with the pressures I am running the normal warning lights are already on most of the time.

The biggest advantage I can see is if the sensors are really accurate you would know the on track pressure of the tires as opposed to the slight drop in pressure you might get after cool down laps, etc.

991carreradriver

For me this is the main issue. I want to know how much heat I am generating though the session. There are so many variables that constant monitoring is the only accurate way to determine the state of your tires. I am not worrying about leaks, I am worrying about tire failure due to excessive heat and pressure, not to mention sliding into a wall because heat has converted my rears to grease.

BradB

That's the main advantage for me. I can actually monitor the pressure on the track, and make more precise adjustments off the track. Much less guesswork. And on-track monitoring of pressure (heat) lets me know in advance when to expect my tires to get greasy. It's the next best thing to having a pit crew radioing data to your headset!

My TPMS, BTW, are less than one pound off from my $85 Longacre liquid filled gauge. YMMV.

Sresites

So I ordered a pair of TPSs from Tire Rack. (RDE011V21) Just got 'em in, opened the package and they're dated August 2014. Near 2-1/2 years old. Typical? If memory serves me right, battery life expectancy is 5-7 years.

Verboden

I cannot say if the TPS manufacture date is typical. However it is my understanding that the units ship in a "sleep" state that has very low battery draw. The units go through a initialization or wakeup routine before being put into service. The typical lifetime is measured from when the units are initialized. I also believe that once they are initialized they cannot be put back into the sleep state.

The Fat Kid

I also have Aug '14 stamped on the TPMS ordered from TR. They are still sitting in the box.

This is what I was thinking.

Sresites

I've put together some information about the TPS found in a Service Info 2009 Tech Intro book:

Wheel electronics
The wheel electronics unit (wheel transmitter, 433 or 315 MHz) is screwed to the rim using the wheel valve.

The wheel electronics unit comprises the following components:
Pressure sensor, temperature sensor, roll switch, measuring and control electronics, receiver and transmitter as well as a battery.
The wheel electronics unit can be triggered and receives send requests from the TPM control unit via four trigger senders. This means that the antenna always receives only one data protocol and this comes from the wheel electronics unit that received the request to send. This gives the system added protection against cross-talk affecting other antennas. Higher transmission power is used due to the longer radio link to the central antenna. The roll switch detects whether the wheel is stationary or turning. This information is used either to start a triggered learning process for a moving wheel or to switch off the wheel electronics unit when the wheel has been stationary for a long time.

To avoid confusion with 1st generation wheel electronics, the new wheel electronics unit can be identified by the modified shape of the housing, the small air filter and the part number stamped on it. A modified data protocol ensures that the wheel electronics unit will not be detected if installed incorrectly and this is stored as a fault in the fault memory.

The following aspects of the system have been optimized by changing the system hardware and software:
Fast learning following a wheel change
Fast detection of a wheel change without re-calibration
Immediate pressure display at the start of a trip
Fast pressure update following tire pressure adjustment
Partial monitoring
Soft warning
Hard warning (puncture)