Proper tire pressure

JPhil

Huh?
Joined
Mar 26, 2008
Messages
1,361
Location
Loveland, Colorado, USA
Does anyone have a method for determining proper tire pressures when changing to a different wheel/tire set up? Like for given axle weight and specific wheel & tire size & type, a tire pressure of X psi for a starting point?

I've been running 28 PSI in my 255/50 17" Nitto Invos, which feels best for driving after experimenting up and down, but now I notice some scalloping on the sipes of the outside tread of the tire. The inside tread pattern is 'coarse' enough it's hard to say if there is any wear pattern developing there. My alignment is good, 0* static camber & 3/16" total toe in. The car handles very well now on the street.

I read somewhere for tires of similar aspect ratio as mine "Vehicle weight divided by 100 plus 2 PSI" but that would put me at 38 PSI. That can't be right.

I know the proper way is with temperature readings & road tests, but I'm not really into getting into that unless I need to. But somewhere there should be a general rule of thumb.

Anybody have any input?
 
Last edited:
275/50/17 in rear 255 up front.....at 35-38 psi on my '72 for some 21 years now.......never an issue.....I make no comments about my home wheel alignment attempts, to which Karsten came to the rescue on that.....
 
That's a good question. Wish I knew the answer.

The outside edges of low profile tires has to be less compliant than the inner tread (rubber spring vs. air spring).
 
Top