you can figure this out of you measure the circumference of the tyre.
Count the teeth on the front sprocket, divide by the number on teeth on the second that is the drive ratio.
Lets say it is 12 front /43 back that means the engine must turn 3.58 times for the back wheel to rotate once. Lets say your tyre circumference is 69 inches.
So 6000 RPM = 1676 rear wheel RPM = 115644 inches, or 9637 feet per minute.
One mile per minute is 5280 feet = 60 Miles per hour, so in this case 6000 RPM would be 109.5 Miles per hour, or 9636/5280 =1.825 X 60.
This assumes 5th gear is 1 to 1, I dont know.
Last edited by yhprum; 2 Sep 2008 at 23:06.