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.
It's a math calculation so the more accurate your measurement......
Easiest way to do it is to measure with a tape measure from the ground to the top of the tire.
My 26" cruiser tires measure out to 26.5"
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.
There can be quite a bit of difference between a 2.125, and a 1.95.
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