[Nemesis]

Originally Posted by choneofakind

Wouldn't that give you the same result as comparing teeth but take a lot more work and time? I've never heard of people comparing the diameter of sprockets; just the teeth.

The final drive ratio is just that; a ratio of the drive shaft sprocket to the rear wheel sprocket that tells you how often the engine will be turning for every revolution of the rear wheel. Seeing as the teeth are all going to be a set distance apart since the chain links are all a set size, it would be easier to just figure out the final drive ratio by comparing the numbers of teeth on each sprocket. In this case, 1 tooth is 1 unit. The diameter doesn't matter because the number of teeth determines the circumference of the sprocket, which is really what matters since the sprockets won't have the same angular velocity, but will have the same radial velocity.

for example, stock gearing is 14/45.
45 / 14 = 3.21
57 / 18 = 3.16 note how similar those two are.

That was a ton easier than needing to find the diameters of each sprocket.

An easier way to determine this would be to believe the poster below:

Originally Posted by Nemesis

It's more about weight than anything else. Gearing, if you calculate it, is the same as stock.