Hi,
You 1st figure out what trap speed you want[top end speed at end of 1/4 mile]. Say that is 125 mph in 4th gear(1 to 1 ratio }.
Then with a tire/gear/speed calculator work backwards to see that at 6,000 rpm with a 26" tall tire you will need 3.50 rear gears.
If you want to road race and go to 140 mph in 4th, then it will be a 3.25 rear gear, etc.
Good Luck,
Perry.
