Tire Pressure Readings, which to trust?

[blueline]

I'll echo Tom's comments and also reiterate that what's most reliable is an accurate tire gauge. However, I was on track yesterday (hot day!) and my TPMS pressure measurements (not the nag "fill" requests) for the GT4 were, as always, exact or within a pound of the gauge readings on all four corners immediately after coming off track. (I measure first thing after getting out of the car.) This is always the case and not just with the GT4 so I'm still a bit puzzled by the difference in the pressures your system is reporting (again, not the "fill" request numbers) vs those of the good tire gauge. If checked immediately one after the other, they should be very close.

As far as AX or any on-track excursions, tire pressures are extremely important (drivers often have them way too high) but the flip side of that importance is, as you alluded to, not overthinking the issue too much. Get them close to where you think they need to be and keep an eye on them.

I will add that AX's present another issue in that you're usually doing your runs on cold tires that are never properly warmed up. A lot of time is spent waiting on your turn to make your run so that needs to be taken into account. Track day sessions or road course racing differs in that you have cold tires on outlaps that will get up to temp relatively quickly (depending on how you drive) with the resulting increase in pressures after which they get waaaay too high if not monitored and adjusted properly.

Bottom line: go have fun!!!