Speedo error

[svede1212]

i changed tires and decided to recal my speeo. my old Nitto 275s were 25.66" and the new Firehawk 285s were a published 25.97". i checked the speed with my GPS and it showed that the speedo was reading way high. well, i finally decided after checking my GPS in another car (it was right on) to try by trial and error to calibrate the speedo. i kept dropping the tire diameter down until i have it very close with a 24.5" size in the tire box and 3.91 (my gear ratio) in the gear. weird. i wish i understood what was going on.

[robfromlouisville]

reset the peak's on your gauge right click and hit reset peak's i had the same speedo error... and i hit reset peak's and it was fine!