You’ll be fine in 4.88 and 33’s. That’s a better setup than on 35’s. Just enjoy it.
35s with 4.56 gears
- Thread starter Joe.B
- Start date
You’ll be fine in 4.88 and 33’s. That’s a better setup than on 35’s. Just enjoy it.
From playing around with the calculator on grimjeeper,
This thread seems insane. So, my jeep is, 2000, 5speed, nv3550, came with a 44 rear luckily, and came 3.73 stock. Now plugging in all that with the stock 30" tire size, compare it to 35" tire size, 4.27 r&p is almost identical vehicle speeds vs rpm as a completely stock setup. (Atleast with my factory options.) 4.10's you loose power, 4.56 you gain a bit, and 4.88 you gain some but you're turning a ton of rpm at freeway speeds.
I would think In any other world senario, you'd basically want to try to match stock factory set up to have the vehicle feel like factory in terms of power. This is why I feel like this 4.88 and 5.13 thing seems insane. At that point what is even the point of having 1st gear. Get to 10 mph and have to shift? Lol.
4.27 isn't really a ratio for Dana 30's for the tj. Well, it's possible but it seems to be down to pinion length and crush sleeve or not. All the other numbers seem to match.
Now, I'm shooting for 35's, 4.10 obviously isn't the choice cause I lose power. However, comparing numbers on the calculator, 4.56 with 35's you'd gain a bit of power vs what my stock jeep had set up with. 4.88's and God forbid 5.13's seem way out in the weeds unless you're cool with listening to your jeep turn 3k rpms at like 65 in 5th. Idk it partially doesn't make sense to me.
I mean, unless stock jeeps were under geared and didn't have power which with all this being said, would make this 4.88 nonsense make more sense.. lol. Not trying to seem like a jerk, but I just don't get the dealio here.
This thread seems insane. So, my jeep is, 2000, 5speed, nv3550, came with a 44 rear luckily, and came 3.73 stock. Now plugging in all that with the stock 30" tire size, compare it to 35" tire size, 4.27 r&p is almost identical vehicle speeds vs rpm as a completely stock setup. (Atleast with my factory options.) 4.10's you loose power, 4.56 you gain a bit, and 4.88 you gain some but you're turning a ton of rpm at freeway speeds.
I would think In any other world senario, you'd basically want to try to match stock factory set up to have the vehicle feel like factory in terms of power. This is why I feel like this 4.88 and 5.13 thing seems insane. At that point what is even the point of having 1st gear. Get to 10 mph and have to shift? Lol.
4.27 isn't really a ratio for Dana 30's for the tj. Well, it's possible but it seems to be down to pinion length and crush sleeve or not. All the other numbers seem to match.
Now, I'm shooting for 35's, 4.10 obviously isn't the choice cause I lose power. However, comparing numbers on the calculator, 4.56 with 35's you'd gain a bit of power vs what my stock jeep had set up with. 4.88's and God forbid 5.13's seem way out in the weeds unless you're cool with listening to your jeep turn 3k rpms at like 65 in 5th. Idk it partially doesn't make sense to me.
I mean, unless stock jeeps were under geared and didn't have power which with all this being said, would make this 4.88 nonsense make more sense.. lol. Not trying to seem like a jerk, but I just don't get the dealio here.
What makes you think your 30" tires are actually that tall? Or that the graph really tells you just how much power larger tires rob?
The problem with those calculators is they let you make many false assumptions and then try to get answers from them.
Well, I mean, I get that point, that makes partial sense. Idk my pops used to run 40's on 4.10's in a blazer back in the 80's and he mudded with that thing all the time and towed things here and there up in Alaska, Now I get that's apples to oranges sort of comparison, it just seems like 4.88 or even 5.13 seems overkill if one ever wanted to travel on a freeway and not be just 2/3rds if the rpm range of the engine.. I mean as it is, I've got 33's on mine and it had 3.73 from the factory and it seems to do fine. It's not exactly fast but I never expected a small brick shaped vehicle to be fast.
Hell the full size truck I had, I was running 35's with 3.73 gears and I could do 100 with that thing and the truck weighed 6700lb and was lifted 10" lol. Thing actually really needed 37's and then I'd have been switching to 4.11's it's also an apples to oranges comparison, but idk even if I'm losing what an inch maybe on tire size sitting on the ground and maybe gaining 15lb or something per tire it still doesn't seem to pan out with that low of gearing. The math doesn't seem to work out unless I wanted a dedicated wheeler.
I get how the calculator can lead to false conclusions. But that low of gearing makes me think nobody that does that travels on a freeway above 65 ever. Lol. Idk.
3000 rpm isn't a ton of rpm. I drove for 10 years at 3000 rpm everyday on my commute. The redline is 5200 rpm.
You're not accounting for the added weight and resistance of larger wheels and tires. You need to be at stock ratio+ to achieve similar performance as a stock setup.
We hear that a lot. It's not insane. It's rational.
How fast do you need to go in 1st gear? You have five of them for a reason.
with your .78 5th gear you want 5.13s for 35s
The stock Rubicon has 4.10 gears, 29" tires, a 4.46 1st gear and a .84 6th gear (NSG370).
The dealio is that the members here have hundreds of years of combined experience.
Last edited:
Which factory gearing would you like to emulate?
42rle / 29.5" /3.73 = 2052rpm @ 70mph
NV3550/29.5"/3.73 = 2320rpm @ 70mph
AX-15 / 29.5" /3.73 = 2349rpm @ 70mph
NSG370/29.5"/3.73 = 2498rpm @ 70mph
32rh / 29.5" / 3.73 = 2974rpm @ 70mph
First, understand that you don't want to regear your TJ for 35's so it ends up with the same rpms at, say, 70 mph as it did when it came with the smaller factory size tires. Bigger tires require more rpms to turn and 35's are substantially harder to turn than its original small factory size tires did. The larger the diameter of tire the more leverage it has against both the drivetrain/engine and its brakes. So you need to regear so it produces higher rpms than it required when it rolled out of the factory.
When you use Grim Jeeper's calculator correctly it shows you won't see 3000 rpms with 35's and 4.88 gearing. What you'll get with your NV3550 and 4.88 gearing is pretty close to 2575 rpms which is a good highway rpm though I believe 5.13 is a slightly better ratio which will produce only 2695 rpms at 70 mph. Personally I like those rpms on the highway and they'll actually produce better mpg too since the engine will be more in its power band than it'd be with 4.56 or, heaven forbid, 4.10 with 35's. Your 4.0 will will be extremely happy on the highway with either of the rpms produced with 4.88 or 5.13. I ran 4.88 for years in my previous TJ with the 5-speed with the same rpms and loved them.
70 mph rpms with the NV3550:
4.88 = 2575
5.13 = 2695
Too many people are afraid they're going to overgear their TJs when regearing to a lower ratio and too many in up undergearing them by being overly cautious. I did that once when I first regeared in 2000 or so for 33" tires. I was afraid to go to 4.56 which was universally recommended for 33's and the 5-speed and went with 4.10 instead. What a mistake, I knew within a couple days of getting the 4.10 gearing that I had made a big mistake in not listening to the recommendations of 4.56 for those 33's.
You won't go wrong with listening to our recommendations. Go with 5.13 or at least no less than 4.88 for your future 35's and you will be really happy with the results.
I've been debating this. I also have an auto on an 05 rubi. With 33's I was thinking 4.88. But I'm not opposed to 5.13. Can you tell me how that lower gearing affected your 1st gear accelerating on road? Does it shift right through 1st into 2nd real fast? Does this negatively impact the auto transmission?
With a Rubi on 33's you should go straight to 5.38 with the automatic. I can't speak to the 1-2 shift but lower axle gears will only help the transmission as it will see less load through it due to the reduced stress provided by the regear downstream.
Your 42RLE automatic is a completely different beast with its extremely steep .69 Overdrive ratio which drops the highway rpms much lower than the 5-speed manual transmission does. That just means it needs a significantly lower axle ratio than the 5-speed manual with its .78 ratio overdrive ratio (5th gear).
For 33's I'd go no less than 5.13 but personally I'd go with 5.38 for your Rubicon. I also have a Rubicon and regeared to 5.38 for my 35's but 5.38, while ok, is really not quite enough gear on the highway. I would have gone for the next lower ratio but 5.38 is as low as the Rubicon lockers will allow. For your 33's 5.38 would be awesome on the highway. And don't let any of the clueless types tell you 5.13 and 5.38 pinion gears are too weak. The redesign they had years ago means they have as much pinion gear tooth engagement as 4.88 does. There are a LOT of us running 5.38 gears in our Rubicons and we love that ratio. It's good for 35's, and much better than the 4.88 I used to have, but it's awesome for 33's.
I'm not totally opposed to 5.38. Does that fit in the stock housing (44's)?
Yes, Revolution came up with a version specifically for the stock front and rear Dana 44 axles and in the right ring gear thickness to work on the factory Rubicon lockers. Lots of folks on this site running that version of 5.38s for 7-8 years now. I believe they came out in 2015 not super long after Revolution opened up.
Since you have a Rubicon yes 5.38 will work fine. You want the "thick" version of the gears from https://www.revolutiongear.com/
These... which is what I installed into my Rubicon.
As far as the pinions being strong, would you go with Revolution over other brands? Thanks for the response. That info helps a lot.
The 42rle with 4.88 pushing 35s is almost exactly the wrong gearing. With overdrive on, it is not deep enough and feels sluggish all around. With overdrive off it is still sluggish at lower speeds, but is a bit too deep on the highway.
As soon as Revolution gets 5.38s in stock, I want to regear.
As soon as Revolution gets 5.38s in stock, I want to regear.
Last edited: