What do you guys use to measure tire pressure?

Do you guys go by the manufactuere reccomended value ?

Its pretty hot here, temps are well beyond 100 F.

Im using the standard 18" wheels on Michelin PS2 tires.

Thanks

Scroll down to the "Similar Threads" below for a tire pressure gauge discussion thread. I have an Intercomp and two Accu-gages for garage and taking to car events, and keep smaller gauges in each car all the time.

There have been several discussions on tire pressures; some always set the pressures just as Porsche recommends, while others don't. I usually start with about 33 psi front and 36 rear with the wheels and tires you have.

I don't know if one should set the pressures any lower when the ambient temperature is expected to reach over 100 F during the day. The tires can probably work okay on the road when they go over 42 psi, but my student's PS2s started to get a little skatey (slippery) when his rear tires got over 42 psi on the track.

Since a "Standard Day" is 29.92" and 59F @ sea level that's probably where the factory recommended pressures work best. Therefore if I was operating the vehicle at 100F ambient temps I'd decrease the pressure a bit to be at the same hot pressure at 100F as you were at around 75-80F. JMHO.

Garage use: a Radio Shack digital LED no longer sold and a $14 Accu-gage dial gauge.
In the Porsche: a Porsche gauge (of course).
Track use: 4" glow-in-the-dark Intercomp dial gauge.

For street use w/18s I run 30F/34R cold (measured at ambient temp) regardless of whether the ambient temp is 30 or 100 deg. Normal street use doesn't get tires very hot. Track use is a completely different story.

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Dan

+1 on the Intercomp (for all around use as well and you can adjust it for your altitude).

Non-liquid filled gauges don't need to adjust for altitude since they measure pressure above the ambient pressure and are not sealed so their internal pressure equals the ambient pressure.

I think you are referring to the adjusting button on higher end liquid filled gauges which are sealed and thus need a means to equalize internal gauge and ambient pressures.

The liquid offers added protection for the gauge mechanism.

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Dan

Yes you are correct.