Here's one for you . if you know what top speed you want to achieve (within reason ) use this formular
S = RPM x T / G
RPM is obviously revs per minute
T is the Circumference of your back tyre in meters
(SAVA tyres are diferent to chinese tyers)
G is your gear ratio (eg 6to54 = 9)
S is speed in meters per minute (60km/h = 1000 meters per minute)
if you don't have a dyno but know that if your mum chases you in the car and you are doing a top speed of 60 klicks your max RPM can be found by
RPM = S / T x G
once you know your max RPM and you know what speed you want use this to get your gearing
G = RPM x T / S
now
my head hurts . make sure you use the right units .I'm going for a lie down.
