I was a little disappointed that for the price it isn't more accurate, my tire size is 25.31" and the calibrator only calibrates in 1/4" increments so when I pass the several radar signs on my way to work each day I am still off by 1 mph on my speedometer. I have calibrated it for 25.25", if I calibrate it for 25.50" then it is off by 1 mph the other direction. It is better than the 5 mph difference that I was originally seeing but for the price could be better.
View more reviews...