How to calibrate the speedometer?
I'm seriously considering upsizing my tires by about 1" diameter, from 33" to 34". I would like to fix the speedo and shift points to accommodate the new size with as little expense and trouble as po...
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That was the case with my F250. The base tires at 245/75R17 were 31" tall and the speedometer over reported the speed. Once I went to the optional 275/70R18's at 33", It was much closer to being accurate. Later switching to 245/70R19.5, the tire height was the same as my 18's.
