CarCrazed

Wondering if anyone is experiencing and can explain the variation in tire pressures during "non-track" driving. With cold tires I set the pressures accurately before driving the GT3. During driving I notice a 1 to 3 psi difference at times, left to right and front to rear. They do seem to change up and down without any logical reason.. My 997.2 GTS TPMS was much more stable and uniform as the tires warmed dring driving. This is why I am wondering if this is a sensor issue or possibly the nature of the MPSC2 tires. Any thoughts would be appreciated.

rubbaman

If you are driving with one side of your car in the sunlight or parked with one side in the sun, those tires will show higher pressures for a time being I've noticed.

CarCrazed

Yes Thanks, I have noticed that happening with the GTS and the GT3. What I am confused about is these changes during normal spirited driving even on a rather straight run on a highway. Not sure what is happening and coupled with my "OCD" it is driving me buggy.

kshu1991

The sun is the answer. My understanding is these tires need heat to grip, so they would generate heat during operation, which will cause the pressure to change.

levd

it's ok, i have the same on TT with MPSS.

Jimmy-D

Put Nitrogen in your tires and you will have less variability to temp changes as it sits ect. Mine are always 28 front 32 rear when it sits(cold) but after it warms up siting a little looking around 30 / 34 but they increase together. This is on the street

SmokinGTS

Yes Go with N2

997rs4.0

Maybe the tire pressure monitor is better in the 991 than 997. First thing I remove when I changed tires. Don't trust the numbers shown if you track. Buy a good gauge and check by yourself.

qbix

As far as I can remember the pressure changes app. 0.1bar for each 10C temperature change in the tire.
Filling a tire with N2 is a task for myth busters but I can tell you straight away that the difference is close to 0.
Air contains 80% of N2 so if you consider properties of O2 vs N2 and include that 20/80 proportion in the equation you gonna get a simple answer that filling a tire with N2 is silly.
My experience is that in my car left and right side never differes by more than 0.1 bar.

CarCrazed

Thanks for the input on the nitrogen pressure variations. Will try that and report back after the Smokies and Sermons trip in May.

tqevo

Is there any way to get rid of the "check tire pressure" warning or to lower the threshold? I tried entering the "circuit" mode at lower target pressures but it didn't allow me set pressures at -4PSI from stock.

Keith Verges - Dallas

OK. I am baffled by this display. Manual says I am supposed to have "Circuit" option but I instead have "circular path."

Keith Verges - Dallas

Odd

Keith Verges - Dallas

Description

Keith Verges - Dallas

Oh, and as for the theory of nitrogen I think that it is supposed to be dry and therefore have less pressure fluctuation with temperature than humid air. The problem is what are you going to do when you need to add or subtract nitrogen? It's not like it is readily available so any time you are in a pinch, you "contaminate" the contents of your tire