Planet 9

jeffreybehr · #1 06-15-2009, 05:47 PM

What's the rule of thumb on tire pressures when wheels are a little wider? For instance, if P recommends, say, 30 and 36 PSI, front/rear, with factory-standard wheel widths, and I buy wheels that are each an inch wider and mount the same tires on them, what should I do with the tire pressures?

My gut tells me to increase pressures a tad, but for all I know, that's backwards.

**Santa Fe** · #2 06-15-2009, 06:43 PM

There should be no difference.

**jim@tirerack** · #3 06-18-2009, 11:06 AM

The tire size won't make a difference. If you want to run a couple PSI more that would be fine. Otherwise just stay with the Porsche OE recommendations.

jeffreybehr · #4 06-19-2009, 05:35 PM

Originally Posted by jim@tirerack

The tire size won't make a difference. If you want to run a couple PSI more that would be fine. Otherwise just stay with the Porsche OE recommendations.

TY, Jim; your colleage Brandon agrees about the couple-more PSI. P's recommendations are 29 and 36; I've gone to 32 and 38 cold.

BTW I wrote of wider wheels, not larger tire sizes.

Jeff G in NE GA · #5 06-20-2009, 05:24 PM

I've actually gone the other way, on my rears, which are 2" wider than stock (295 on 11") - running 35 cold with good results. I know there are a LOT of differences, but as race cars get lighter and tires get wider, we run less PSI - i.e. 17 PSI cold. (Not suggesting anyone run that - just an example for a completely different car).