Gear upgrade for 37's

[JTSUSN]

Getting time for some new shoes! I have a Sport S with max toe (4:10 gears) I currently run 35's, thinking about moving up to 37's. My current ratio should be able to handle them right?

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[Jrgunn5150]

Sure it can.

More specifically, the 8 speed can. Has enough ratios to choose from to be able to figure it out.

I tell people all the time, if you can regear, you should, and you'll be happier. If you can't, you don't have to, and you won't die or explode.

 

[JTSUSN]

Thanks! I'm a little gun shy concerning gears, I had a JK with stock 3:21's and a manual running 35's (before I knew better) plus towing my boat (which isnt all that big) never ever got into 6th and towing never got into 5th. Needless to say I wound up loosing the rear end. So I just wanted to get some ideas before pulling the trigger on the 37'3.

 

[Jrgunn5150]

The OEM strategy is to run the thing into top gear ASAP so it can idle down the road and get 0.004 better MPG.

So, it'll still hit 8th, it just won't hold it. If you have a Tazer to correct the ECM for the tire size, it helps with the shifting a lot.

 

[JmattNYC]

Hey Buddy, what set up you will have? True 37s and how heavy your wheel and tire combo will be? Eventuality you will prob wont to regear anyway. Make sure you do all the correct calibrations/etc.
For gears i think keep it 4:56/4:88 dana Spicer gears is safe choice. Ensure you get master kit and while you at it mybe installed front locker!

 

[GL64]

37s with 4.10s drops your relative ratio to about 3.88 : 1. You'd need to go up to at least 4.56 to get it back into the stock 4.10 ballpark.

You're right on the cusp with 4.10s. It'll be fine. Will it do it? Sure. Your transmission may hunt for 8th and slip in and out, but no big deal really. You might feel a slight loss of torque when towing. If/when you can, spring for 4.88s and be done with it.

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