Use a GPS to see how many mph off the speed display is from the actual speed. Then, go to the SpeedoHealer website, scroll down to the Online Calculator and plug in the numbers to see the calibration value you need.
If you do not have access to a GPS you can get close to the right results by using highway mile markers, a stopwatch and a little math. Go for a 10-mile ride at as close to an exact fixed speed as you can and time how long it took you to travel that distance. Get out your calculator to see how fast you were actually traveling compared to what your display indicated.
If you do not have access to a GPS you can get close to the right results by using highway mile markers, a stopwatch and a little math. Go for a 10-mile ride at as close to an exact fixed speed as you can and time how long it took you to travel that distance. Get out your calculator to see how fast you were actually traveling compared to what your display indicated.