mismatch between speedo and odometer
Adjust the clock spring pressure changes the speedometer needle position.
As 67dart273 noted the odometer is gear driven.
Speedo shop would spin the head the correct rpm for say 60mph (1 mile per minute) the odometer would tick off 1 mile in 60 seconds. Then they adjust the spring to set the needle for the correct speed of 60mph.
Then the odometer and speedometer would be correct for a particular input rpm.
Your rear gear and tire size and speedo gear combo sets the closest setting to the correct vehicle speed.
Here is a head where the spring adjuster is not being held in place properly. The adjuster is pointing almost streight up.
A speedo shop could probably fix it.
And bouncing needles....
If the red box part ( which spins at speedo gear speed by the speedo cable) makes any contact with the green arrow part which is attached to the needle, the needle will bounce
Adjust the clock spring pressure changes the speedometer needle position.
As 67dart273 noted the odometer is gear driven.
Speedo shop would spin the head the correct rpm for say 60mph (1 mile per minute) the odometer would tick off 1 mile in 60 seconds. Then they adjust the spring to set the needle for the correct speed of 60mph.
Then the odometer and speedometer would be correct for a particular input rpm.
Your rear gear and tire size and speedo gear combo sets the closest setting to the correct vehicle speed.
Here is a head where the spring adjuster is not being held in place properly. The adjuster is pointing almost streight up.
A speedo shop could probably fix it.
And bouncing needles....
If the red box part ( which spins at speedo gear speed by the speedo cable) makes any contact with the green arrow part which is attached to the needle, the needle will bounce
