[PJP]

How accurate is the tire pressure reading provided by the TPMS system as displayed on the dashboard and/or via OnStar, as compared to your run of the mill gauge? I have a gauge that seems to be consistently around 2 PSI higher than what the car reports. My instinct is to go with the car, but that's not necessarily correct.


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[Submariner409]

You only check tire pressures cold or after a drive of less than 1 mile. Normal tire heating raises pressures, so "hot" pressures are inaccurate. Never bleed hot tires - that pressure rise is built into the vehicle recommendations. The "maximum inflation pressure" molded into the tire sidewall is for the speed runs at Bonneville only. Run tires at the door sticker recommended pressures for city and local driving, 2 psi higher (cold) for long road trips for slightly increased fuel economy.

Underinflated tires wear the outer treadbands; overinflation wears the center bands.

The TPMS system is, at best a SWAG (Scientific Wild Ass Guess), so a good (not cheap) dial type tire pressure gauge is your friend.

 

[Theroider]

My TPMS matches my manual pressure gauge perfectly. I usually leave the tire pressure readout on my display. I see the pressure in all 4 tires fluctuate when I drive. That's normal. Leave the car out overnight and check the pressure in the morning and make any necessary adjustments.

 

[PJP]

Thanks, everyone. I've ordered a quality gauge with a round dial (from Joe's Racing, which seems to have lots of good reviews). I'll see how it compares to the TPMS output. The gauge I am using now is admittedly cheap and hard to rely on for precise readings.

 

[AAIIIC]

The TPMS system is, at best a SWAG (Scientific Wild Ass Guess), so a good (not cheap) dial type tire pressure gauge is your friend.

I'm with Theroider - I find TPMS to match my very expensive analog dial gauge quite nicely.