Ok so I realize most folks are looking at gearing for 33's and above, but not me. I recently re-geared the TJ (4.0, NSG370, Dana 44 rear, Dana 30 front) to 4.10's since I only have 31's and might put on 32's in the spring. After over 10 years with a 4" lift, I have realized I personally have no desire or need to run a larger tire with a tall lift. 31's are plenty sufficient with a small 2" or less lift/spacer height.
That said, the LJ, with the 42RLE, Dana 30 front and 44 rear, has its stock 3.73's. It's surprisingly noticeable how much of a difference there is in going from the 31's it previously had, to the 32's it now has. I'm constantly finding the trans downshifting, or myself turning off OD, on any amount of hill other than a tiny 1 percent grade. Meanwhile, the TJ cruises along nicely at 75 without the need to downshift even on the steepest hill going to town.
That said, I am debating between 4.88's and 5.13's on the LJ.
Before throwing out suggestions, please note my use case. Weekend cruising, multi-day camping trips, possibly a 15 day 'overland' trip once a year. It will have a hard top, and the typical accessories (winch, lights, fridge, recovery gear, a couple spare parts, backpack, water, food) your typical weekend camping setup. Thus it will of course be heavier than it is now, and heavier than most folks who have trail rigs that they tow. I suspect close to GVW once a passenger is added. I also do plan on towing a small trailer for camping trips longer than a night. Plan is for a trailer weight hopefully no more than 2500. The diff's at some point will receive Eaton E-lockers, but probably not for another year.
I lean toward 5.13's even for 31's or 32's due to the expected weight of camping and towing combined with higher elevations and steeper hills in my area. However, highway speeds in my area are 80, though I dislike going that speed.
According to grimjeeper (with incorrectly factoring tire diameter), the difference between the two is only about 150 rpm. That said, the 5.13's still put me in a better position RPM wise when traveling at 60, which is the speed limit for highways when I visit home. It probably would put the RPM's a little too high to have sustained 80mph speeds for my comfort, not that it will hurt anything other than my ears. But again, I prefer cruising around 75 max anyway.
One concern I do have is lower speed cruising between 20-40 mph. I don't want to be spinning the engine at 3500 rpms just to putz around at 35 which appears it can be the case.
That said, the LJ, with the 42RLE, Dana 30 front and 44 rear, has its stock 3.73's. It's surprisingly noticeable how much of a difference there is in going from the 31's it previously had, to the 32's it now has. I'm constantly finding the trans downshifting, or myself turning off OD, on any amount of hill other than a tiny 1 percent grade. Meanwhile, the TJ cruises along nicely at 75 without the need to downshift even on the steepest hill going to town.
That said, I am debating between 4.88's and 5.13's on the LJ.
Before throwing out suggestions, please note my use case. Weekend cruising, multi-day camping trips, possibly a 15 day 'overland' trip once a year. It will have a hard top, and the typical accessories (winch, lights, fridge, recovery gear, a couple spare parts, backpack, water, food) your typical weekend camping setup. Thus it will of course be heavier than it is now, and heavier than most folks who have trail rigs that they tow. I suspect close to GVW once a passenger is added. I also do plan on towing a small trailer for camping trips longer than a night. Plan is for a trailer weight hopefully no more than 2500. The diff's at some point will receive Eaton E-lockers, but probably not for another year.
I lean toward 5.13's even for 31's or 32's due to the expected weight of camping and towing combined with higher elevations and steeper hills in my area. However, highway speeds in my area are 80, though I dislike going that speed.
According to grimjeeper (with incorrectly factoring tire diameter), the difference between the two is only about 150 rpm. That said, the 5.13's still put me in a better position RPM wise when traveling at 60, which is the speed limit for highways when I visit home. It probably would put the RPM's a little too high to have sustained 80mph speeds for my comfort, not that it will hurt anything other than my ears. But again, I prefer cruising around 75 max anyway.
One concern I do have is lower speed cruising between 20-40 mph. I don't want to be spinning the engine at 3500 rpms just to putz around at 35 which appears it can be the case.
