Speedometer 10MPH off with stock wheels.????Why

[RotaryRyan]

Hey guys, my speedo is consistently 10 MPH fast. I checked it with radar detectors and with other cars speedometers. It was with stock wheels and all. Im just wandering. Why?????

ANy ideas? I have since gotten 17 inch wheels and havent tested it again.

 

[sjgYFZ200]

Stock wheels might not be the problem, because you can always throw a different size tire on it...assuming you had stock tires I'm not sure, but maybe the speedometer is off a few clicks? Does it read zero at a stop?

 

[RotaryRyan]

yeah it reads 0 at a stop. It had 205/55/16 's on it