TPMS Accuracy

[mgattmch]

The Tire Pressure Monitoring System (TPMS) on my car consistently shows a difference in pressure reading versus a hand held electronic pressure gauge. Generally about 2-3 psi difference. Which is the more accurate, the TPMS or hand held pressure gauge? Does anyone else have a similar experience?

[Opie55]

There was a thread like this a couple months ago. Assuming you have a quality dial gauge I would trust that. My TPMS reads at least 2 pounds lower than both my gauges, which read the same, so I trust them.

[thebmw]

Funny, I was thinking this exact thing a couple weeks ago. I measure my pressures to be exact 0.1 every time and the car is always 1.5 to 2 PSI lower.

[mgattmch]

I am going to retract my original post. Strangely, the day after I posted my original question the TPMS readings and electronic hand held pressure gauge readings were essentially identical, within +/- 0.2psi. Maybe related to an ongoing calibration function as I drove the car. Bottom line, I trust the TPMS readings.

[thebmw]

I still notice a difference between my digital gauge and TPMS. I use my digital gauge number as the max limit and TPMS as the minimum limit. Most importantly though, I make sure both the front and back tires are the same pressures relative to each other.

[ezmaass]

My indicator came on last night as the temps have been dropping into the 20's and 30's. I filled them up today and did notice that there's a small variance between what my gauge shows and the in-car reading. Not huge but up to maybe 2 PSI, and it did tend to show on the lower side (in car) versus the gauge.

I wonder if it's just calibrated that way for some extra margin of safety? Either way, not a huge deal.

[tcabill]

I have calibrated instrumentation that can measure PSIG to .01 and the TPMS on my old F10 was always within 3 tenths of a PSI. I you have air in your tires you will see a significant change in pressure as the tire temp changes, with nitrogen not so much.