What is the proper tire pressure? Please help

mine are at 34psi brother

 

I have Goodyear Eagle F1 Assymetrics on my 1999 355. What should mine be at?

 

Proper tire pressure is dependent on the tires and dependent on your driving style and finally dependent on how the car is set up.

Basically, you want to run the rear tires at optimal traction and then find the right combination of tire pressures and rear end ride height so that the front end neither pushes nor the rear end gets loose.

I have my rear ride height set so that the front and rear tires can use the same pressures. On the road I use 34 PSI, cold in the garage, which gets to 38 PSI warm: and at the track I use 32 PSI (coolish) that allows the tires to run at 40 PSI hot on the track.

To a first order, if the front tires have too much grip, you can reduce the grip with lower pressures, however, if you need more than 2 PSI (or so) difference between front and rear; you should use this as a sign that the rear ride height is incorrectly set for this set of tires. 1-2 turns up at the rear increases oversteer, 1-2 turns down at the rear increases understeer.

{And if you are going to the trouble to set the rear ride height, you should also do this on a set of scales and cornerweight the thing at the same time.}

 

32 front 29 back is written on the car.

Everyone should go and check their tire pressure now that spring is here. Every year several exotics and their owners get destroyed from rotted/under inflated tires.

 

Dry is dry, wet is wet and psi is psi - the tire doesn't care what gas is in it, be it air, ozone, or nitrogen. The nitrogen is a larger molecule and doesn't escape the rubber confines as easily as oxygen (air), so the pressure should remain more stable over time. Temperature changes will still affect the pressure.