PSI ?'s About Plus Size Tire/Wheel

[George Roffe]

Mark wrote:

>Thanks, Frank and Bruce. Once I wrapped my brain around that problem for a
>little longer... I came to the same conclusion Bruce did. Theoretically, the
>psi should be higher... I just wonder how much the volume difference is, or
>if it's because of the lower profile. I'll try wrapping my brain around
>that, later.

Uh, you've got your brain around this backwards.  Ever notice that a racing
bicycle tire requires a very high pressure while large tires require lower
pressures?  I'll bet the volume of a wider, lower profile tire is pretty
similar to the narrower, higher profile tire.  About the same pressures
should be required.

There are a few of factors that may influence your final decision.

1. Higher pressures will likely change direction more quickly.
2. Higher pressures are going to protect the wheel rim a *bit* more.
3. Wear....  you may have to adjust whatever pressure you use depending
upon the wear you experience.

>I can't begin to describe how much more "alive" my car feels. Definitely
>feels lighter on it's "feet". I'm going to put a few hundred miles on the
>tires, though, before I start scrubbing them... don't want no chunks coming
>off the tires.

Be careful.  It can suck you in because it *feels* more responsive.  I wore
the center tread of a set of tires almost bald many years ago (while the
edges were nearly new) because of the same thing you're talking about.

George Roffe