[zinner]

Hello

I was at the track this weekend and I dropped my tire pressure down to about 30F/34R. At any rate I went out on the track and I started getting warning messages and got forced down to comfort settings and it ruined my session. I like the idea of TPMS but I don't like the idea of it being so rigid. A tire at 31.9 psi is not flat. Is there a way to change the threshold to something more reasonable.

Even as the tires warmed up and pressure was at 33F 38R it was still going nuts with messages, it's very distracting. It only went away when I did the TPMS reset.

It's a 2015 F30 N55 Manual Msport

[Billfitz]

Originally Posted by zinner

I was at the track this weekend and I dropped my tire pressure down to about 30F/34R.

That's probably not a good setting.
https://www.tirerack.com/tires/tiret....jsp?techid=58

Instinctively one might assume that lower pressure = wider footprint = better traction, but that's not necessarily the case.
In any event, once you decide on where you want your pressure for the track if it's lower than for the street reset your TPMS at that pressure and leave it there. The system never complains if your pressure is higher than nominal.

[zinner]

To be clear I was lowering my pressure over 2 lbs increments to try to see how handling changed, I didn't just do that out of the gate, I didn't assume that going from 34F/39R to 30F/34R would would cause the car to ruin my fun. I started my day at stock pressure and my instructor mentioned I should probably drop the pressure due to the way the car was handling.

Thanks for the tip, that is exactly what I ended up doing in the end.

[jkwhar]

Originally Posted by zinner

To be clear I was lowering my pressure over 2 lbs increments to try to see how handling changed, I didn't just do that out of the gate, I didn't assume that going from 34F/39R to 30F/34R would would cause the car to ruin my fun. I started my day at stock pressure and my instructor mentioned I should probably drop the pressure due to the way the car was handling.

Thanks for the tip, that is exactly what I ended up doing in the end.

Wouldn't lowering the pressure and then re-measuring/resetting the TPMS on the idrive reset the threshold? I don't think the car knows/cares what psi it should be running but rather how much psi dropped since the TPMS reset.

[zinner]

jkwhar, that could be the case, every other car I have owned has obeyed some preset PSI value.

[jkwhar]

Originally Posted by zinner

jkwhar, that could be the case, every other car I have owned has obeyed some preset PSI value.

The f30's came with different wheel sizes which means different pressure. So I'm 99% sure it just checks the threshold more than the actual value.

[Billfitz]

Originally Posted by jkwhar

The f30's came with different wheel sizes which means different pressure. So I'm 99% sure it just checks the threshold more than the actual value.

It checks the value, you can see that when you check the pressures. Lots of models use different pressures in the front versus rear, so it has to take that into consideration. When you do a calibration it does so to each tire individually, at whatever the pressure is in each tire when the calibration takes place. You could even calibrate with different pressures on all four tires if you wanted to.

every other car I have owned has obeyed some preset PSI value.

It gives a warning when pressure falls to about 4 PSI lower than what it was measured at when calibrated. About a week after I got mine it threw a warning when one tire went to 31 PSI, which I though odd as my pressure is supposed to be 32 PSI. I figured out that for whatever reason mine was initially calibrated at 35 PSI. I filled all four to 32 PSI, did a calibration, no warnings after that. I check it at least once a month, more in winter when the Tom Brady effect causes pressure to drop more than leakage accounts for, so none have ever gone low enough to trigger another warning.