This is a great way to see "how fast" someone could relatively go on a motor bike at a certain rpm. I used it with a 26" rim 11tooth drive sprocket, 36tooth rear sprocket, and an rpm of 2200. It gave me the speed of 52mph. But somehow this does not seem right. But I don't know when I buid my bike I will put a tach and a speed gauge to see how close it is.
Here is my version of gear calc. It's small Open Office's spread sheet. It allows to calculate spead depends of wheel size, engine's RPMs and sprockets sizes in standard engine set and Shift Kit with standard bikes gears on rear wheel.
I hope it will be usefull for somebody
It'll be nice to see some suggestions and ideas to bild up this calculator.