| **how to calculate gearing?** | gsxrawd
*Jun 8, 2002 10:45 PM* | | let's say i have a big ring at 53 and the small cog at 12, is it 53 divided by 12 times 27 (for 700c wheels)? what about if I have 650c wheels? do I times it by 26? |
| **gear inches...** | C-40
*Jun 9, 2002 4:43 AM* | | Your forumula is correct (ring/cog x 27), but the gear- inch formula does not give a value that means anything. It's just a gear ratio times a constant.
If you want to compare a 650c wheel to a 700c, you need to know the diameter of each tire. Then take the ratio of the 650 tire diameter divided by the 700 tire diameter to get an equivalent gear-inch value.
For all practical purposes, a 650c bike would use a cassette with a one-tooth smaller top cog and a two-tooth smaller big cog to be geared close to the same (an 11-21 instead of a 12-23). |
| **Yup nm** | the dad
*Jun 9, 2002 7:30 AM* | | |
| **re: how to calculate gearing?** | shortstroke
*Jun 11, 2002 8:09 PM* | | Save you the trouble, try this link...
http://www.pagesz.net/~scotty/gear-form.html |
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