Reviewed By William W (COLUMBUS, OH) Reviewed for a
—6/27/2015 12:06 PM
I initially set the unit for 34" tires, the diameter of my Toyo ATIIs in 295 60r20, the speedometer was actually a couple mph over. After some downward-tweaking for tire inflation level, I setting the unit to correct for 32.75 inch tires got my speedometer accurate to within less than 0.5mph error compared to Garmin GPS. Keep in mind that actual tire diameter is dependent on how many psi you are running, so getting things right on the money may take some tweaking.