Speedometer recalibration: is it possible?

[Grant Eaton]

I ended up buying a set of Pirelli Scorpion Zeros from www.tirerack.com. I paid about $154 each plus $70 shipping (total cost was about $700).

I bought the 285/55/R18 size. At 30.34", the diameter of the tire is about 2.5% larger than stock, so the speedometer will be a little off, but not too much.

The other wide-tire option, 285/50/R18, was about 1.1% smaller than stock at 29.22" diameter. (Stock is 29.57".) I figured I would rather make an extra 2.5% on my business mileage expense reports with the bigger tires. Plus, the 285/55/R18's were $40 cheaper for the set than the 285/50/R18's.

I don't want to do any cladding trimming and from everything I read, this size tire should fit without rubbing the cladding or anywhere else.

(I hope.)