No reasonably priced pressure gauge is going to be 100% accurate. Likewise, no TPMS is going to be 100% accurate. What’s important is that they are reasonably close and relatively consistent.
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- The TireMinder® transmitters are accurate to +/- 3%.
- TireMinder® brand pressure gauges (mechanical or digital) are among the most accurate on the market at ± 1 to 2 PSI.
So, if you are running 100 PSI in your tires, you could have a gauge reading 2 psi high and a TPMS transmitter reading 3 psi low leaving a difference of 5 PSI. This is not uncommon and is considered totally acceptable. We have had calls from customers doing their initial installation saying all 8 or 10 TireMinder® transmitters are reading 9 to 11 pounds low. Can you guess what the problem is? What is important to understand is that the TireMinder® TPMS (and any other brand for that matter) is designed to warn you of changes. For example, it really does not care whether it starts at 97 psi or 108 psi. It is the changes and deviations from the baselines you need to know about.
So, please look at “the big picture”. You may use your trusty pressure gauge as the “standard” or you can use the TPMS as the standard. The important point is that they are all relatively consistent.