Thinking very serously about installing some gears into my XJ. Stock gearing is starting to put a toll onto my engine (190k) with my 32x10.50s. What is the correct gear ratio that I should run w/ 32s to get the power bands back similar to what they were with stock tires? it is my DD but so I dont want anything crazy, i just need it not to work so hard. On the highway at 70 mph it shifts up and down with inclines with the cruise set so i know its working to hard to turn the tires. Are there any decent kits that are good but somewhat inexpensive?

 

31x10.50's put my speedo 5mph, the correct the speedometer would mean going from 3.07's to 3.54's. (I did the math once and it seems like thats what I needed).
I would say that your going to be looking at 3.73's or 4.11/4.10's to get the engine in its sweet spot with the larger tires.

Since I got a set of 3.54 ratio axles thats what the Money Pit is going to get under it.

 

32" (new tire) / 28.29" (stock tire) = 1.1311 X 3.55 (stock gear ratio) = 4.02 gear ratio to get back to stock equivalent with 32" tires. So, 4.10s would be good.

 

X2 4:10's are the right choice. Especially if you ever want to go 33's.

 

im doin the same. will that increase gas millage to? or lower it

 

Its always better to go lower gear anyway since your larger tires use more torque to get moving. So always go the next gear lower.

 

Rather doubt it will increase it.....doing the math just gets u back to the equivalent gear ratio......doesn't take into consideration that 32s will probably weigh 20-30 lbs more per tire than 28s. Even with 4.10s, it's still harder to turn 'em over just not as hard as if u stayed with 3.55s.

 

cool deal, sounds like ill be goin with 4.10s. thanks for the info.