My speedo is about 5mph off at low speeds (it says im going faster than I actually am) and anywhere from 10 to 20mph at higher speeds. I know that most speedometers were calibrated to show you going faster than you actually were, but this seems to be a little in excess. Also it seems to "jump" from 60 to 70 and from 75 to 85. Any ideas?
Could be the speedometer head needs lubricating. Could be the cable needs lubricating or is binding in the sheath. Cable may not be fully seated in speedo head/damaged.Damaged driven gear on end of cable at tranny...Have you changed the cars rear tire size?? gone to a taller/shorter tire???
Your speedo will be out by a percentage thats why its a larger variance at higher speeds. Tire size,gear ratio and speedo gear tooth count all come into play. Likely something has been changed on the car at some point to put it out that much. My car with 4:11's is actually pretty close with a white gear. Only out about 5 mph at 60 mph. Good enough for me.
