[G8mike]

For the engineers out there. If you have a 2.73 final drive versus a 3.31 final drive, do the individual gear ratios not change, or are they all in relation to that final ratio, therefore a 4.21 1st gear remains a 4.21 gear but is 'shorter' when applied to a 3.31 rear end. Am I getting that right???

[RougeRiver]

G8mike;214355 Wrote:For the engineers out there. If you have a 2.73 final drive versus a 3.31 final drive, do the individual gear ratios not change, or are they all in relation to that final ratio, therefore a 4.21 1st gear remains a 4.21 gear but is 'shorter' when applied to a 3.31 rear end. Am I getting that right???

You have it right.

Let us say that your engine has 100lbs of torque.

With a 3.31 final drive, the torque applied to the wheels is

(100)(4.21)(3.31) = 1393.51lbs


With a final drive of 2.73, the torque applied to the wheels is

(100)(4.21)(2.73) = 1149.33lbs

A taller final drive gives less bite per gear change but lowers ICE shaft rotation rate to deliver a given vehicle speed. That combined with a higher load on the ICE contributes to fuel economy.

[G8mike]

Thanks Rouge!