thinking about re gearing and wondering what are some peoples opinions/experience with them on and off road. thanks

 

Subscribed!!
I'm in the same boat.....

 

I think tire size is pretty important with this. What are you running/might you be running in the future?

 

It would be a lot easier to give any kind of opinion if we knew a little about what Jeep you have such as year, tire size, what axles, engine and if it's auto or manual trans.

 

Great subject, throw in my experience.
Went to 31" tires, lost 5 mpg and tons of low end pull.
Went to 4.10s and the gas mileage came back to stock, and low end is even slightly better than stock. Highway speeds feel like a stocker. This combo works well for the type of 4 wheelin I do, lots of fire roads and trails, and recent 4000 km drive to Baja and desert fun. Worked great.

BUT.... if I wanted to rock climb then it would have to be 4.56s, and probably 33s too.

So my response is: 4.10s are mandatory with 31s if you love your XJ (no pressure)

FYI: 4.0 with automatic

 

^^^^X2.5....without that info, those 2 numbers r pretty much meaningless.

 

97 auto 3.55
35" & 33" (I switch em out)

 

Do the arithmetic......28" tall stock tire height divided into 35" tall tire = 1.25. 1.25 times 3.55 is 4.44........or 4.56 gears r needed to have basically the same mechanical leverage as a stock height tire and stock 3.55 gears.

Pop quiz........what ratio gets u back close to stock mechanical leverage when running 33" tall tires?




(answer - 4.10 using the same arithmetic)

 

4.5 inch lift 31 unch tires 10.5 wide getting 32s next 94 xj sport

 

i have a 4.0l with a manual transmission and i have 33 inch tires. changed my 3.07s for 4.56s and i am very overgeared it has a LOT more torque than stock if u have a manual and run 33s get 4.10s if you do highway 4.56s if u like torque.

i could put 35x12.50s on and be about stock at 4.56

 

I never understood that. Everyone always says to go to 4.56 with 33's and an AW4, but that seems completely wrong. According to those gear ratio calculators, 4.10's would be the best.

 

Don't forget the added resistance of the rolling stock, and the the increased drag from being lifted.

 

I am running 4.88s with 35s on my 99 xj 4.0 auto went to them from 3.55s and my mpg increased pretty well and power is back to normal slightly better I would say 4.56s would have been best though for the 35s

 

Mathematically, 4.56 with 35" or 4.10 with 33" will get u back to, or very close to, the mechanical leverage of stock 3.55 with stock 28" tires.

+1 to this.....the arithmetic doesn't compensate for the extra weight of big tires/lift kits. Depending on your calculations, I'd think it would be better to error toward the taller side (numerically).

 

If you have 35s go 4.88s. You will not regret it. Good gas milage and being able to do burn outs with giant 35/14s will make you very happy lol