[PollKat]

I couldn't find anything on Tirerack.com but the guy at the friendly local Pep Boys had a big shiny Book of Rims and Upsizing, he said up to 255/65/16 is cool on the rim. P

The Pep Boys around here (i.m.o.) aren't all that swift. But, I think they nailed this one. Here is a calculator for your speedometer. You may have to scroll down a bit. Tire/Speedometer calculator
HERE