Tire pressure question-too high psi?
 

Ok so this is probably a really stupid question, but I wanted to get some input. I recently put new Nitto tires on my Z. The sidewall says that the max pressure should not exceed 50 psi. Anyway, I set them all at 45 psi, however when my car was at the dealership they said that was "excessively high and dangerous" so they set them at 35 psi. So what is the right pressure? If 45 was too high then why doesn't the tire say 50?

Thanks in advance.

You need to have room for expansion when tires get hot.

Thats why they recommend 35 psi and that they be checked when cold.
http://i576.photobucket.com/albums/s...m/DSC01415.jpg

Ok. Thanks. I guess ill leave them at 35 then. I just don't understand why the tire doesn't just say max pressure 35 psi lol

The tire can handle 50 psi but if you actually set that pressure you would be running on a tiny contact patch in the middle of the tire due to the pressure ballooning it out, you'd wear your tires out quickly and have reduced grip. Typically you increase pressure as you increase load so that the two forces cancel each other out. 35 psi cold as recommended on the car gives you the best tire contact patch and therefor best traction for daily driving. Same tire on a different car may experience different loads and thus call for different pressures.

The TPMS triggers for the warning light are approximately < 30 psi and > 40 psi. Racing on track can generate a lot of heat and thus generate a lot of extra pressure, so that may require dropping the cold pressure slightly in order to reach an ideal hot pressure of 35-40 psi.