What gear ratio should I install in my Jeep Wrangler TJ / LJ? (and other re-gearing FAQs)
- Thread starter Chris
- Start date
More BB fodder for his disciples.
https://wranglertjforum.com/threads/peak-crusing-rpm.19088/post-309719
https://wranglertjforum.com/threads/peak-crusing-rpm.19088/post-309719
Yes, and as was explained to BB the recommendations in this thread are for HIGHWAY DRIVING not crawling.
Hasselblad
TJ Enthusiast
Hi again, after a couple years (and permission from the purse holder) the regearing is a go.
To refresh my situation:
Daily driver in the mountains of Utah (Wasatch back) with regular steep grades on the highway, between 6 and 8k above sea level. Steep moderately rough logging roads several times a year. Some light 1600 or so pounds towing of the quad on a small flatbed up into the Uintas a few trips a year.
06 rubi
4.0
42rle
32" that will become 33" with next tire purchase in a couple years.
HP Tuner with fixed shift points (will retune if need be for new gears)
2923 rpm at 75 mph if I go with 5.38 gears. Does that track?
And would that be the wiser choice over 5.13? Judging by some of the posts in the thread that mention as low as possible with the 42rle, I am thinking yes?
Edit: assuming I input the right numbers into the grim page.
To refresh my situation:
Daily driver in the mountains of Utah (Wasatch back) with regular steep grades on the highway, between 6 and 8k above sea level. Steep moderately rough logging roads several times a year. Some light 1600 or so pounds towing of the quad on a small flatbed up into the Uintas a few trips a year.
06 rubi
4.0
42rle
32" that will become 33" with next tire purchase in a couple years.
HP Tuner with fixed shift points (will retune if need be for new gears)
2923 rpm at 75 mph if I go with 5.38 gears. Does that track?
And would that be the wiser choice over 5.13? Judging by some of the posts in the thread that mention as low as possible with the 42rle, I am thinking yes?
Edit: assuming I input the right numbers into the grim page.
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This is what happens when you put helpful people on your ignore list.
I recently downsized my tires to 30 inch tires (from 31 inch).
Now I am running 4.0, 42RLE, 4.56 gears and 30 inch tires.
It drives amazing, especially acceleration with overdrive disabled. When on highway, I get around 2550RPM around 70MPH, it drives amazing.
Seems like most of the bad rap that 42RLE is getting is related to the bad gearing.
It seems to me that the correct gearing for it is(4.0 engine):
30 - 4.56
31 - 4.88
32 and higher- 5.13
What you guys think?
Now I am running 4.0, 42RLE, 4.56 gears and 30 inch tires.
It drives amazing, especially acceleration with overdrive disabled. When on highway, I get around 2550RPM around 70MPH, it drives amazing.
Seems like most of the bad rap that 42RLE is getting is related to the bad gearing.
It seems to me that the correct gearing for it is(4.0 engine):
30 - 4.56
31 - 4.88
32 and higher- 5.13
What you guys think?
yes your tire/gear information does apply well with your automatic transmission.
Hasselblad
TJ Enthusiast
Chris' chart states 5.13, Jerry and company recommended 5.13 https://wranglertjforum.com/threads/can’t-seem-to-find-revolution-gears-anywhere.52632/#post-917256
I think it may be at the point where more opinions are not necessarily helpful.
Will be a year or two before the rubi needs the new rubber, giving the increase to 33". It would be awesome if there was a consensus of 42rle + 33" =5.38, but I am not seeing one. Hell, even the folks here in Utah (pretty respected shop for all things wrangler) only advised 4.88.
Here's my present mind: I do not want to go too weak a gearing, but have no thoughts on going to 35"s. If I go 5.38 I might regret it being on the deep side. After all of the reading, all of the opinions, all of the theorycraft with the grim jeeper page, 5.13 kind of seems like the sweet spot... on paper. Trust me, I look at my rubicon axles and have given thought to the 5.38, after all it has that capability over the non-rubicon axles, why not take advantage, right?
I'd love to see a compelling case for the 5.38s with 33"s if there is one. Preferably before she goes under the wrench on the 10th.
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I assume Jerry and company would go 5.38 for 33's if it was an option. Before he left the forum, he regularly said that while 5.38 was the best he could do for 35's, it was still barely enough or not enough. The numbers support the idea of 5.38 for 33's, aside from unfortunate high driveshaft speeds that likely would need to be dealt with in some fashion.
If it were me I would intend on running 5.38's for 33's, if I had the axles to do so. Obviously that is another hindrance that sometimes decides the ratio for the owner.
Although I highly respect the opinion of Chirs on this forum, you will often receive feedback from others with such terms as, "we like", or "folks on this site", and "what I like". Now these terms are fine and ok for such site because we are on "their" site asking "their" opinion, but keep in mind that most opinions on this site are just how a particular combination of tire size, gear size, etc., works for a given jeep. The true answer lies on your own set of circumstances such as use of the vehicle, mostly highway, off-road, 50/50, whether your in the mountains or flat land, and of course your jeep specifically such as engine size, transmission type, etc. So what is my point? Well, my point is to take all these points into consideration and come up with your best answer to meet your specific needs. Most importantly, have fun and enjoy your jeep every step of the way and don't get lost in opinions.
ps..... don't worry about members mocking you or me for our thoughts. Its just how they are!
Understand that as far as the 42RLE is concerned, you can never go to deep.
If you have Rubicon axles I see no reason not to put 5.38 gears in there.
Besides, your 33s are only temporary anyways. You'll be running 35s before you know it.
Hasselblad
TJ Enthusiast
I am too old to be bothered by a good mocking.
Also @Chris, I doubt my lifespan has 35s after the current 32s and then the 33s.
Hasselblad
TJ Enthusiast
In any event I have a message in to the shop to see when the drop dead day is to decide. Uncertain if they stock all ratios.
Another review of 5.13 with 33s and 42rle (and in the mountains):
https://wranglertjforum.com/threads/my-review-of-5-13-gears-with-33s-and-42rle.62562/
Another review of 5.13 with 33s and 42rle (and in the mountains):
https://wranglertjforum.com/threads/my-review-of-5-13-gears-with-33s-and-42rle.62562/
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Don't forget it's propensity to over heat when off roading. But yes 0.69:1 overdrive ratio is a touch too high for the power plants Jeep used in the TJs with stock gearing.
Two things are true about the 42rle. It is an irritating transmission and most of the problems people have with it are largely addressed with deep gearing. The problem is that most refuse to regear deep enough to get the rpms as close to 3k rpm at 75mph as is feasible.
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