I have the stock ZHP wheel/tire combo. I notice every time I drive by a speed sensor it's says I'm going 3 mph slower than my speedo indicates. I had this same situation with my truck and ended up going up a size when I purchased new tires. That worked out perfectly.

Has anybody ever went up a tire size on their style 135s ? I was thinking of going from:

Front 225/40/18, Rear 255/35/18

to

Front 225/45/18, Rear 255/40/18

According to the online tire calculator, that change would net a 2.7 mph increase which would make the speedo almost exactly correct and maybe provide a little smoother ride.

Has anybody ever tried it? Does that tire combo fit or will it rub?