# Rear sprocket diameters

Has anybody ever done measurements on a rear sprocket to see what a difference 1 tooth makes in the sprockets diameter? Just curious as to what the diameter difference would be going from a 52 to a 51 tooth. My guess would be 1/8 inch.

Has anybody ever done measurements on a rear sprocket to see what a difference 1 tooth makes in the sprockets diameter? Just curious as to what the diameter difference would be going from a 52 to a 51 tooth. My guess would be 1/8 inch.
Do the math:

You know that the pitch of your 520 chain is 5/8". That being the case, a 52 tooth sprocket will have a circumference of 52x.625=32.5", and a 51 would be 5/8 shorter at 31.875. Dividing by Pi, that gives you 10.345" and 10.146" respectively for the diameters, and the difference is .199", or just over 3/16".

Do the math:

You know that the pitch of your 520 chain is 5/8". That being the case, a 52 tooth sprocket will have a circumference of 52x.625=32.5", and a 51 would be 5/8 shorter at 31.875. Dividing by Pi, that gives you 10.345" and 10.146" respectively for the diameters, and the difference is .199", or just over 3/16".

damn, gray you are smart. I would have never figured out how to do that. Thank you.

Geometry 101

They told you you'd want to know it later.

Geometry 101

They told you you'd want to know it later.

Yeah!.....but how do you still remember it after all those years?

All those formula's?

If you just remember that they exist, you can look them up when you want them.