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**Accelo** · 01-04-2023, 09:01 PM

With your current size tires;
If you go to the 21T gear your spedomete3r will be off by 2.3% fast.
If you go to the 22T gear your spedomete3r will be off by 2.32% slow

You should have the smaller of the two 8T gears. (The 1.76" OD gear).

I get a 7% difference, in speed, using 55/59mph and your existing tire size and the 8/21T gear? Almost three times the what the calculated speed difference should be. Go figure.

01-04-2023, 09:01 PM	#4
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,358	Re: 72 Saginaw 3 speed Speedo Drive gear? With your current size tires; If you go to the 21T gear your spedomete3r will be off by 2.3% fast. If you go to the 22T gear your spedomete3r will be off by 2.32% slow You should have the smaller of the two 8T gears. (The 1.76" OD gear). I get a 7% difference, in speed, using 55/59mph and your existing tire size and the 8/21T gear? Almost three times the what the calculated speed difference should be. Go figure.