33” tires: 4.56 or 4.88 gears?

http://www.grimmjeeper.com/gears.html
Enter your information into the gear calculator and see what your RPM's would be. If it isn't a being driven on freeway speeds then IMO I would run 4.88 gears. But I like my rigs geared low. To get your actual tire height measure from the center of your wheel/hub to the ground & double it. This will give you a more accurate RPM estimate.
 
Also, it’s not a daily driver and it never sees the highway or speeds above 60 mph.
You probably could get away with 5.13s or even 5.38 if it never sees above 60.

Personally I would do 5.38 (if you have Dana 44 front/rear) or 5.13 if 5.38 is not an option. Deeper gearing for off road and city driving.

5.38s wouldn’t make it impossible to do freeway speeds, but you won’t get the best fuel mileage. At 70 mph you would be cranking around 3k RPM, which is fine for the engine. (A stock Rubicon with NSG370 cranks 2.7k RPM at 70 from the factory.)
 
Last edited:
Same year, motor, trans as you.
4.56 is what you want. I drove around for a few months with 4.88 and 33”s until I could buy 35”s. It was great off road. But highway the rpms were to high.
 
  • Like
Reactions: JMT
Same year, motor, trans as you.
4.56 is what you want. I drove around for a few months with 4.88 and 33”s until I could buy 35”s. It was great off road. But highway the rpms were to high.
Check out his second post.
Also, it’s not a daily driver and it never sees the highway or speeds above 60 mph.
 
I have a rubi with an automatic. In overdrive with 33s my 4.10 is giving me about 1850 rpm at actual 60 mph. I am guessing 4.56 would bring that up to around 2200 or so. Anyone have some real numbers
 
33's, 5speed, 4.0L, with corrected speedo, 4.56 gears,
20170125_075340.jpg
 
Unfortunately, the answer is not cut and dry.

I love my 4.56 gears, 97' 5 speed 4.0l

@ac_ loves his 4.88 gears in his 98' 5 speed 4.0l

Same engine, same transmission, different views.

You will see an improvement from either set.
 
  • Like
Reactions: Midtenn and ac_
I have a rubi with an automatic. In overdrive with 33s my 4.10 is giving me about 1850 rpm at actual 60 mph. I am guessing 4.56 would bring that up to around 2200 or so. Anyone have some real numbers
Because of the overdrive in your auto. There are shifting barriers. I am not fully versed in the auto. But i have never seen anyone say use 4.56 in an auto with overdrive.
 
  • Like
Reactions: starkey480 and JMT
I vote 4.88 especially if it’s not a DD and not much highway. Im “overgeared” for my tire size and it’s fine. The lower gears work great crawling.
 
Because of the overdrive in your auto. There are shifting barriers. I am not fully versed in the auto. But i have never seen anyone say use 4.56 in an
Because of the overdrive in your auto. There are shifting barriers. I am not fully versed in the auto. But i have never seen anyone say use 4.56 in an auto with overdrive.
The auto works great with the 4.10 until that .69 od comes in. It does alot of highway driving. It will be 4.56 or 31 inch tires.
 
2004 TJ with 4” lift and 33’s, 4.0 and 5 speed manual. Looking at a gear swap, I know the majority go with 456, but how would 488 be with 33’s?
I'd only consider 4.88 for 33's if your Jeep seldom sees the highway. Even offroad 4.56 is more than enough for 33's considering most offroading is done with the transfer case in 4Lo. Only if you think you may eventually go to 35" tires would I go 4.88 with your 5-speed manual transmission and 4.0L engine.

I have a rubi with an automatic. In overdrive with 33s my 4.10 is giving me about 1850 rpm at actual 60 mph. I am guessing 4.56 would bring that up to around 2200 or so. Anyone have some real numbers
Ron your 4-speed automatic changes the usual recommendation for an axle ratio, due to its exceptionally steep .69 Overdrive ratio. At a MINIMUM for your 33" tires you need 4.88 but personally I'd go 5.13. Yes 4.56 is perfect for 33's with a 5-speed manual but don't pay any attention to recommendations made for those with manual transmissions.

My TJ has the same 4-speed automatic with 35" tires and its previous owner cluelessly only regeared it to 4.88 and it was constantly lugging on the highway, I had to keep turning the overdrive off. I regeared last year to 5.38 which really helped a lot, my mpg even went from <12 mpg to >14 mpg.

Bottom line is for your 33's I'd definitely go 5.13 if it was my TJ.
 
  • Like
Reactions: Ephry73
A concern I have, that hasn't been voiced, is pinion size. I know with the 30 front axle and 4.88 gears the pinion diameter is extremely small.
 
A concern I have, that hasn't been voiced, is pinion size. I know with the 30 front axle and 4.88 gears the pinion diameter is extremely small.

People run 5.13 gears in the Dana 30. As long as you buy quality and not eBay special $50 gear sets. You don’t have much to worry about.
 
  • Like
Reactions: reddvltj
People run 5.13 gears in the Dana 30. As long as you buy quality and not eBay special $50 gear sets. You don’t have much to worry about.
Good to know, thanks. Years ago when I had my 97 I was advised against anything lower than 4.56 in my Dana 30 by a reputable drive line shop...