Reviewed By Jeff J (Diamondhead, MS) —3/26/2015 5:18 AM
I have a 15 F350 and changed from the stock 34" tires and went to 37" tires and installed the Speedo Calibrator. One thing to remember when entering tire info even if you look up the numbers in height. The stock tires are 34.1" vs the 36.54..you need to measure once the tires are installed on the truck and on level ground. My 37's once compressed are about 36.25 Entering this number got me closer to the real GPS on my phone vs running 2 mph slower at 75mph. Ill be using 35.75, to get it closer.