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Sheldon Brown's Gear Calculator
Translation of this article: French
You need to enter data for at least one chainring, and at least
one sprocket unless you choose a stock cassette.
Not all items listed are current -- especially, see cassette listing.
Listing of hubs is A>Z by manufacturer, then by number of speeds, type and age.
Fichtel & Sachs, Sachs and SRAM are the same series of hubs, shown together.
This page covers all-derailer systems, and the more common internal-gear hubs.
Another page covers antique and rare internal-gear hubs as well.
Clicking on "calculate" generates two new output pages: a full-size one, and a small one which you might print out and tape to your bicycle's handlebar stem for reference. The small one will overlay the large one in a browser which supports tabs.
If you do a calculation, then bring those to the front, subsequent "results" windows from subsequent calculations may be hidden behind them.
For multiple calculations, you should close each set of results in turn, not hide them.
The SRAM/Sachs 3 x 7, 3 x 8 and 3 x 9 and the Sturmey-Archer CS- RF3 and CS-RK3
are the only production internal-gear hubs designed to use rear sprocket clusters.
but other models are included in the list for the benefit of tinkerers -- see discussion.
Thanks to Stephen D. Cohen and Timothy Lipetz for programming help
If you want more numbers, including speed and cadence data,
Jake Odell has a more elaborate gear calculator:
Tom Kunicki has a calculator with specific features useful for fixed-gear and singlespeed riders:
John Allen has pages giving exact, fractional ratios calculated from gear tooth counts:
If you would like to make a link or bookmark to this page, the URL is:
Last Updated: by Harriet Fell