I've been sifting through a number of threads trying to get a sense about what it's like living with 4.88's and a 6-speed when running 33" tires. Not sure I've got the warm and fuzzy I was hoping for so I thought I'd reach for more opinions and experience. If this is your set-up I'd like to hear from you.

I currently have the 3.21 gears and 2.72 low range of the non-Rubi. I really need to improve my crawl ratio but I don't want to run out of gears on the highway.

For those who are in a similar boat... I found by using one of the slick calculators someone posted that 4th gear running 3.21's results in an RPM profile that nicely matches 6th gear running 4.88's. Drive on the freeway in 4th gear (max) and you'll get a sense of what it would be like to live with 4.88's on the road. My jeep is not my daily driver but I drove it to work today just to try this, hoping it would answer my question for me. I'm disappointed to say I'm still up in the air on the subject. A 3,000 rpm cruise (~70 mph) might get annoying after a while, but it's not terrible.

As an aside, probably like many others who buy 33" tires, I don't see 35's in this Jeep's future. With that in mind I'm not going to make a decision based on "when you upgrade to 35's" rationale (though you're welcome to try!).

In any case, I'd like to hear about your direct experience with this combination, second-hand stories, and anything else you may have to offer on the subject.

Thanks for your help.
Ron

 

Have you considered just getting a rubicon t-case? It bolts right in without any mods, and would be cheaper than regearing. That is, if you are ok with the 3.21's and 33's. I think 4.88's and 33's is nuts. I have 4.56's in my other jeep with 34's and HWY driving is painful (granted its only a 4sp, but even if it had OD, it would not be much better). But then I only put maybe 1500 miles a year on it.

 

I'm planning on going w/ 4.88 and 33's. However, mine is an auto. If you look at the gear ratio charts you will notice that 4.88 w/ 33's is about the same as 5.13 w/35's

I've had my share of "built" Jeeps. My plans for the JK is a mild build, (by my standards). I have a front leveling spacer that I will install as soon, as Winter is over, along with JKS disco's. Rock rails and skid plates are already installed. I'm planning on a Detriot rear and am still considering the front locker. Gears will be 4.88 and tires will be an, as yet to be descided, brand of 33 inch MT.

Even with 33's I will probably still add the front axle "C' gussets" along with new front axle shafts.And, I do have a set of 16 inch steel wheels w/ 4" BS I used on my old WJ. No wheel spacers for me

 

I've got 33.s and am considering going with 4.56 gear set

 

have you considered 4.10s?

 

What about all these yahoos rolling around with stock 3.73s and their 35" tires?? Are they all UBER Nuts??

https://www.jk-forum.com/forums/modified-jk-tech-2/3-73-gears-35s-19423/

 

Naw. They will be lacking on acceleration sure. But their HWY RPM will be reletively low, so they should get decent fuel economy. I drove my old '75 cherokee with 3.54's and 34" tires for many years without any issues. I even towed and hauled with it. Granted I had a V8 with a T18a 4sp (granny low first).

It still surprises me that so many people say you need 5.13's for 35" tires. Either the V6 is the JK really is as worthless as I think it is, or these people never drive on the freeway. Because to me, 3k rpm at 70mph is unacceptable for trips of any distance (with the chryco 3.8L, as its a poorly balanced V6. A nice 4cyl would cruise at that rpm all day).

 

with the Auto 3.73s are fine however on the longer stretches and going up hills it suffers and can't use OD with anything I think the 4.10's wouold be great for the 33's and the guys runnig the 3.73's most have Manuals if they have auto's they are just hurting themselves. I have the 3.73's and 33's and from what I am told it is good to go. not yet sure as I haven't been home to drive and all the Mods happened after I left for the Sand Box. but I will be home in a few months to see how she handles. If you wanna go 33's find some one on here getting rid of ther 4.10's and get an install kit, I doubt that you will need a new carrier however you may as I am not totally sure about that. Any one else? Know?

 

Good suggestion. I have thought about it, and was considering this an AND option rather that an OR. I'd really like to see Teraflex or AA come out with a bolt-on low-low unit that works with the 6-speed. In any case, I'm keeping this on my list of potential things to spend money on!

I'm going to do the same, though I wasn't sure if they are a real option as of now, having seen a lot of conflicting information. It would probably be a more suitable choice for 33's, and still good if moving to 35's later.

Yes, but after considering the labor cost for an installation of any gear set, I thought I'd go for more and try to really make gains in the crawling department.


Thanks for all of your feedback and suggestions. Still undecided.

 

I think I may be able to be of some help here. I have an 08 with 6 speed. It had the 3.21 gears from the factory. I went to 35" tires and chose the 4.88 package. It worked out very well 65mph 6th gear tach reading 2600rpm. So if you are going to stay with 33" tires you will definetly want to look at 4.11 or 4.56 gears 4.88 would be way to low. Good luck.