I'm looking for confirmation of my method of calculating my 3 gear transmission ratio and my final drive ratio.
Building my first 2.2 Sporty using Capra axles. Trying to pay close attention to gear ratios etc. Bought a compact three gear transmission with a ratio of 11.5:1. That ratio with the stock Capra axle ratio of 7.2:1 give me a final of ~80. I want to get down to ~50. I'd like to start doing that with pinion changes.
Transmission specs given to me (with 12T pinion) are: 48t locker gear to a 14t to a 40t spur.
With a 12T pinion, I calculated:
Gear ratio of 3.33:1 (40/12 = 3.33)
Transmission ratio of 3.43:1 (48/14 = 3.43)
Transmission final of 11.4:1 (3.33 x 3.43 = 11.4:1)
With a 20T pinion, I calculated:
Gear ratio of 2.00:1 (40/20 = 2)
Transmission ratio of 3.43:1 (48/14 = 3.43)
Transmission final of 6.86:1 (2.00 x 3.43 = 6.86)
Final Drive Ratio = (trans ratio) 6.86:1 x (axle ratio) 7.2:1 = 49.3
Still may end up with a smaller pinion due to space restrictions but I'm still closer than I was with at 12T pinion. Either way, just want to verify my thinking.
Any feedback appreciated.
Building my first 2.2 Sporty using Capra axles. Trying to pay close attention to gear ratios etc. Bought a compact three gear transmission with a ratio of 11.5:1. That ratio with the stock Capra axle ratio of 7.2:1 give me a final of ~80. I want to get down to ~50. I'd like to start doing that with pinion changes.
Transmission specs given to me (with 12T pinion) are: 48t locker gear to a 14t to a 40t spur.
With a 12T pinion, I calculated:
Gear ratio of 3.33:1 (40/12 = 3.33)
Transmission ratio of 3.43:1 (48/14 = 3.43)
Transmission final of 11.4:1 (3.33 x 3.43 = 11.4:1)
With a 20T pinion, I calculated:
Gear ratio of 2.00:1 (40/20 = 2)
Transmission ratio of 3.43:1 (48/14 = 3.43)
Transmission final of 6.86:1 (2.00 x 3.43 = 6.86)
Final Drive Ratio = (trans ratio) 6.86:1 x (axle ratio) 7.2:1 = 49.3
Still may end up with a smaller pinion due to space restrictions but I'm still closer than I was with at 12T pinion. Either way, just want to verify my thinking.
Any feedback appreciated.
Last edited: