unusual tire wear

My 2002 M3 has Mich Pilot Sport tires. the right rear is worn in the center of the tread. The outer edges are fine, just worn down in the center. a local tire store rep told me it may be due to over-inflation. I had recently checked the pressure and it was coming in at 38 psi.

Any ideas on what would cause this?

Try a different gauge?

isn't 38psi a bit too much?

I run 40 psi all around on my M3.

But I am running 265s all around.

I used the same gauge on all of the tires. Only the right rear is showing this problem.

I went and got a digital gauge just to be sure. After a short drive, the rear tires were registering at 40 psi. They must increase a little from heat, but only a pound or so.

I'm going to watch it closer but still wondering why the problem is only with the right rear.

I agree, that's usually a result of overinflation. What's the recommended tire pressure on the door sticker?

Tire pressure increases with temperature, yes, sometimes as much as 5 psi, depending on the ambient air temp and how aggressively you drive.

However, except for racing/track use, you set tire pressures cold.

No idea with one tire. Unless at some point it was overinflated for a while.