Speedometer repair

[Leo Whitlock]

Originally Posted by TBONE1964

Here is how you test speedometer calibration vs odometer calibration.

Speedometer calibration is what speed the speedometer states you are going per the needle position.

Odometer calibration states how far your odometer moves over a measured mile distance. If you drive one measured mile on a road, then your odometer should reflect that in exactly one mile. If it does not, then you need to change the gearing in your tail shaft housing to get the odometer to record an exact mile while driving a measured road mile. This is determined by rear gear ratio and tire diameter. Most transmission shops can provide you with the correct gears for the odometer if they have the correct information.

If your speedometer moves exactly one mile for one measured mile of driving, then you odometer gears in the trans are OK and your speedometer is out of calibration. The only way to correct this is to remove the speedometer from the cluster and have a reputable speedometer shop do a calibration on it.

Using GPS as a comparison is a good way to tell if your speedometer is or is not calibrated correctly.

Let me know if you have any questions. I have the ability to do speedometer calibration if needed.

Take care,
Tom

Tom
I will double check with gps, as I remember the odometer was right and the speed was wrong, can you tell me if the stock 62 was a red/orange needle or a white one. I have 3 or 4 heads and don't remember which is which.
I may be needing your services