Gearing Question????

[rt2878]

Got a 9 Inch lift and rolling on 37"s now. Its a 2500 cummins, with I believe 3.42 gear ratio. what gears can I step up to so that I will regain what little power I lost. and over all get more get up and go ???

 

[Stephens]

4.56 is what Im getting on 35s.

Consider 4.88s?

 

[knucklebuster27]

New Tire Diameter / Old tire diameter * old gear ratio = new gear ratio

37 / 31 * 3.42 = 4.08

If this was a diesel I would say 4.10

If this was a Hemi I would go with 4.88

 

[rt2878]

Thanks for the help ill look into 4.10's

 

[Jerry1984]

I agree with the 4.10s with the cummins. Most will say go one step deeper after the above calculations due to added rolling resistance and mass, but with the cummins you will be fine with 4.10s unless you do a lot of city, stop and go, driving then bump up to 4.56.

 

[loveracing1988]

I agree with the 4.10s with the cummins. Most will say go one step deeper after the above calculations due to added rolling resistance and mass, but with the cummins you will be fine with 4.10s unless you do a lot of city, stop and go, driving then bump up to 4.56.

If there was a step between 4.10's and 4.56's that would be perfect. Unfortunately they no longer make a 4.30 or a 4.44 for both the front and rear axle in the HD's though unless I can't find them.