The odometer is direct gear driven, the only thing that can
effect it's accuracy is a change in the rear gear ratio or
the tire diameter or a change in the driven gear at the transmission.
The needle on the other hand, is driven by a magnetic field
and can easily loose calibration from a dry bearing, a bad
bearing or damage to the air gap clearance if someone messed
with the head, the air gap sets the calibration.
A jerky needle is almost always caused by a worn or
sticking cable or cable housing.
dg
Last edited by Denny Graham; 02/16/2016 1:23 AM.
