Thanks Jon and Shop Shark

SS, I found your thread in 2018:
https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1315306/1950-chev-truck-speedometer.html

and at amazon: now $15.39
https://www.amazon.com/Powerful-Neo...0+x+10+x+5&qid=1616446983&sr=8-2

I think I got this right, the spinning shaft, turns the magnet, which then spins the cup over it spinning it 180-270 degrees against the resistance of the spring. Then as everything slows down the needle returns to 0. So once magnets weaken, the cup doesnt spin so fast, and looks slow, 150mph then turns to 26 MPH. Strange that magnet 'strength doesn't change the speed of the cup around it.

Also, So I dont have to take it apart, or is it good to to put the magnets against the truck speedo magnet, as close as possible. I imagine this is best. Right?

I just ordered the magnets. Thanks SS !

Jon, I used your WD40 trick and lubed up everything. thanks! Will make sure that it spins easy also, no binding on the thin top x-bar bushing just under the needle.

Waiting on amazon now.
Clem

Clem Donahue; Berkeley
'51 chevy 3600 3/4 ton, rebuilt 235; 6V still, 96% stock
'65 ford ranchero