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JSeery · 08-30-2019, 07:50 PM

It all depends on what you want to end up with. Run the number and see what appeals to you. There is a link in a recent thread that you can plug the numbers into and see what you will end up with (mph) in each gear.

The final drive ratio is the transmission gear ratio X the rear axle ratio. Good performance street numbers are in the 8.0 to 9.5 range for first gear. Economy range is >8.0 (These are just rule of thumb number by the way)

16/28 1.75 X 3.78 = 6.6 Up in the economy range
15/29 1.93 X 3.78 = 7.3 A little better, but still in the eco range

This is just first gear, of course 3rd is 1:1 so 1.00 X 3.78 = 3.78

Tires come into play here, but this the final drive numbers. Now, where are you wanting to end up? IMO these gears would work better with a lower rear axle ratio, but again that is kinda up to the user.

08-30-2019, 07:50 PM	#2
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: "40 gear selection It all depends on what you want to end up with. Run the number and see what appeals to you. There is a link in a recent thread that you can plug the numbers into and see what you will end up with (mph) in each gear. The final drive ratio is the transmission gear ratio X the rear axle ratio. Good performance street numbers are in the 8.0 to 9.5 range for first gear. Economy range is >8.0 (These are just rule of thumb number by the way) 16/28 1.75 X 3.78 = 6.6 Up in the economy range 15/29 1.93 X 3.78 = 7.3 A little better, but still in the eco range This is just first gear, of course 3rd is 1:1 so 1.00 X 3.78 = 3.78 Tires come into play here, but this the final drive numbers. Now, where are you wanting to end up? IMO these gears would work better with a lower rear axle ratio, but again that is kinda up to the user. Last edited by JSeery; 08-30-2019 at 08:11 PM.