TPM overestimates actual cold tire pressures

[kindofblue]

The TPM on our 2021 Y has consistently read 42 psi. I checked it a couple days ago before heading out on a road trip and the accurate tire pressure gauge read 40 to 40.5 psi. When I used a calibrated air pump to put them to 42.5 for the trip the TPMs then read 45 psi. Just wanted to alert others to this discrepancy.

 

[BodegaBay]

The TPM on our 2021 Y has consistently read 42 psi. I checked it a couple days ago before heading out on a road trip and the accurate tire pressure gauge read 40 to 40.5 psi. When I used a calibrated air pump to put them to 42.5 for the trip the TPMs then read 45 psi. Just wanted to alert others to this discrepancy.

Thank you for the sanity check regarding the TPM but my experience was opposite on a MYP. After 400mi I was wondering why the ride was harshly stiff (were the PZero's sidewalls that stiff?) and took a gauge to read the cold tire pressure. It was reading 45psi cold with tire pressure gauge vs. 42psi cold TPM numbers. I lowered it 3psi and the ride is much more bearable.

 

[Silicon Desert]

I think I said it elsewhere. These are not large unexpected differences. Not a big deal. TPMS are not that accurate in most cases. Keep in mind the real reason of a TPMS. It just needs to be reasonably accurate to warn you of a potentially dangerously low pressure while driving.

In other words, noting a difference from 45 to 35 or 45 to 25, not just a couple psi

 

[kindofblue]

I think I said it elsewhere. These are not large unexpected differences. Not a big deal. TPMS are not that accurate in most cases. Keep in mind the real reason of a TPMS. It just needs to be reasonably accurate to warn you of a potentially dangerously low pressure while driving.

In other words, noting a difference from 45 to 35 or 45 to 25, not just a couple psi

I couldn't agree more. At the same time the lesson here is to not rely on TPMS as accurate PSI measures and that's the case with many cars I've owned with TPMS.

 

[Eeekkk]

I like to use the recommended TPMS as much as possible. My last two service visit; SA put my tires to 48 TPMS and I just lower it myself.