question about gear ratio calculator

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,508
11
38
Ridin' inSane Diego, CA.
i downloaded the jim sitton gear ratio calc. in wheel diameter do put acual size of wheel and tire or just the the size specified on tire?
The size of the tire will do.......20", 24", 26", 29er. The larger diameter will attain a higher speed than that of a smaller diameter. A smaller diameter will have faster acceleration than the larger.

dnut
 

biknut

Well-Known Member
Sep 28, 2010
6,511
207
63
Dallas
The way I do it is to put a piece of tape on the rim, and on the ground next to the rim. Them roll the wheel one revolution, and put another piece of tape on the ground next to the rim. Now measure the distance between the 2 pieces of tape on the ground. Divide this number by 3 to get the diameter.

There can be quite a bit of difference between a 2.125, and a 1.95.
 
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