I need some info.

[Green Leader]

I have an 01' TJ with an auto tranny, Teralow & 3.73 gears w/ 35" tires and this is a daily driver. I am thinking of jumping to 37" tires. I am going to need to chage my gears and I can't decide on what to go with 4.10 or 4.56 etc. I am looking for feedback on what to do. hopefully someone out there as done this already and can tell me what they did and if they like it or not. I would also like to know onroad vs offroad changes with the gears for example freeway speed & RPM's you know the technical stuff. Being a daily driver i want to maximize the benefits of boths worlds as much as i can. Any info and questions would be great. thanks

 

[gijohn40]

I don't have actual data but if it was me I would go with 4.56 gears... you will notice it on and off road...

I have a cj7 with 35" tires and I run 4.56 gears and its nice to have the low end...

 

[Spork]

I wouldn't bother going from 3.73 to 4.10 there just isn't enough of a change to make it worth it.

 

[Rusted]

Here is a quick chart to get you an idea

http://jeephorizons.com/tech/rpmchart.html

With 3.73 gears and 35" tires you are geared a little higher than where you should be now.

If you want to go to 37" tires you should probably be lookinig at 4.56 or even 4.88 gears

Those gears are close enough that I don't think you will notice much difference offroad. Besides you have the tera low kit to give you the really good offroad gearing. I think the biggest difference will be with the highway driving.


Here is another calculator that maybe more useful

http://www.4lo.com/calc/gearratio.htm

with 35" tires, 3.73 gears and 60 MPH your engine is 2149 RPM
with 37" tires, 4.56 gears and 60 MPH your engine will be 2484 RPM
with 37" tires, 4.88 gears and 60 MPH your engine will be 2659 RPM

 

[crazyyo]

i would go with 4.88 imo

 

[soda blaster]

I would go with the 4.56 gears you keep a bigger pinion gear and the difference between 4.88 and 4.56 is almost noticeable if your going to go with the smaller pinion gears might as well go with 5.13's

 

[mbryson]

If you're set on the 37" tires, I'd go with the 4.88s. However with stock TJ axles, I'd stick to 35" tires.

 

[Gravy]

If you're set on the 37" tires, I'd go with the 4.88s. However with stock TJ axles, I'd stick to 35" tires.

agreed.

4.88's or on the high side 5.13's are what you want for 37's