What The

I've seen all the posts about tire pressures for the stock rims.

My question is:

Are tire pressures recommended the same for all tires??

i.e. i have 225/40/18 F & 235/40/18R's. Should the tire pressure be 32-36psi like other people have recommended for stock tires, or should the tire pressure be higher because of the smaller sidewalls?

Phantom? Unicron? Tire Rack Guys?

Thanks!

p.s. Did a search but have not seen anything like this posted before.

Penforhire

Sidewall height alone is not a perfect indicator of stiffness. Some tires are very soft or stiff for their sidewall height. You generally want to use as much tread width as possible (lowest pressure), without rolling over onto the sidewalls during hard cornering. This all assumes your alignment is where you 'want' it. At Auto-X pressure is commonly determined by marking the sidewall-tread interface with white shoe polish, starting with high pressure, and dropping pressure until the edge of the tread (but no sidewall) is used in extreme corners. A more accurate but error-prone method is the tire pyrometer (getting inside/middle/outside temps equal).

Even after this 'baseline' tire pressure is determined you might prefer more or less pressure in fronts or rears to match your driving style. You may need different pressures to balance the car if your tires are radically different front/rear. Higher pressure in front might give you crisp turn-in and low slip angles but may also reduce ultimate grip. Higher pressure in rear may cause more oversteer, which is fun in controlled doses but not the fast way around the track.

Umm, don't forget to dial in your tire pressures when the tires are warmed up. Pressures will rise and if you dial-in at cold you'll be running too much PSI hot.

s2ktaxi

You should be able to start with the OEM recommended pressures and then tune from there.