As far as % error between the odometer and the speedometer, they should be similar, but there is probably an offset in favor of the speedometer reading higher. Most speedometer makers design the analog needle type speedometer to read a little on the high side (maybe 1 to 3 MPH at 60 MPH). I guess that is to cover their butts for any one who gets a ticket and blames the instrument
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With the newer electronic transmissions and programmable pinion factors, you can get a little more precise on the odometer. Swapping the pinion gears on the older trannies is still done on a best effort basis with the bias (from most speedometer shops) to set the speedometer to read high, knowing that a lot of people are going to exceed the speed limit.
With the newer electronic transmissions and programmable pinion factors, you can get a little more precise on the odometer. Swapping the pinion gears on the older trannies is still done on a best effort basis with the bias (from most speedometer shops) to set the speedometer to read high, knowing that a lot of people are going to exceed the speed limit.