TPMS woes anybody else

[Snorman]

My TPMS were working fine, and while I recognize that they are not extremely responsive, nor necessarily as accurate as a good gauge, I was using them at Sebring for reference. They were relatively close to my Longacre, so I would run up to ~35-37# and pit in to bleed down to 33#. Once the fronts hit 35+ understeer starts to get much more pronounced anyway.
Last week, after the detailer was done I put everything back to recommended...35/29. Took the car out and the pressures on TPMS were out of whack. So on Friday night, double checked and they were spot on at 35/29. However, TPMS is reading RF 30-31#, LR 35#...the LF and RR seem relatively accurate. There is no calibration available for the TPMS system, so figuring that I'll need to have the dealer replace at least two sensors.
Anybody else have problems with them?
Thanks.
S.

[Dr.Ron]

I had one wheel's pressure suddenly out of whack & had the yellow idiot light on for the TPMS. The dealer replaced "the module." It didn't sound like the tpms sensor in the wheel.

I'm sure they'll fix you up easily.

Ron

[ek1]

Had the car since august. I have yet to see a single instance of tpms being less than 1.5 psi off my Longacre gauge. Its always wrong. When I was at SEMA, I spoke to at least 2 TPMS manufacturers (one claimed to supply TPMS systems to all the luxury car brands). Both said that their systems are not meant to be precise, in both the sampling rate or the quantity of the measurement.

It's not just the Viper either. I have 2 other cars with TPMS and they are both off by 1-2 PSI. Furthermore, most of the gauges sold in Auto stores are off too (if you compare them to a calibrated gauge like Longacre).

I treat TPMS as a binary "OK/NOT OK" tool. It's also useful for reminding me to increase tire pressure after the track day is over. For everything else, Longacre gauge does the job.

[Bruce H.]

2 of 4 are generally accurate, another reads 1 psi high and the last .5 psi low. Good as a rough guide only.

[Snorman]

Had the car since august. I have yet to see a single instance of tpms being less than 1.5 psi off my Longacre gauge. Its always wrong. When I was at SEMA, I spoke to at least 2 TPMS manufacturers (one claimed to supply TPMS systems to all the luxury car brands). Both said that their systems are not meant to be precise, in both the sampling rate or the quantity of the measurement.

It's not just the Viper either. I have 2 other cars with TPMS and they are both off by 1-2 PSI. Furthermore, most of the gauges sold in Auto stores are off too (if you compare them to a calibrated gauge like Longacre).

I treat TPMS as a binary "OK/NOT OK" tool. It's also useful for reminding me to increase tire pressure after the track day is over. For everything else, Longacre gauge does the job.

Agree, they are only relatively accurate. But I have two that are ~5 psi off.
And absolutely...you can only use a quality tire pressure gauge, not the junk you buy in an auto parts store.
S.

[Snorman]

2 of 4 are generally accurate, another reads 1 psi high and the last .5 psi low. Good as a rough guide only.

Bruce...exactly. I was only using TPMS for reference. In fact, a friend was at Sebring with me on the 2nd day and hopped the hot pit wall to bleed down the tires. We compared from his gauge to TPMS and hot there was only a ~1 psi delta. Strange that this is happening after tracking the car.
S.