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-   -   4.88s with 33s (http://www.wranglerforum.com/f218/4-88s-with-33s-295681.html)

Signalman 09-16-2013 10:24 AM

4.88s with 33s
 
Does anyone have any pros or cons of 4.88 gears with 33 inch tires with an I6 engine?

reno92 09-16-2013 10:33 AM

Don't have experience, bit it sounds like overkill to me unless it's just a trail rig. I feel 4:10 is fine for a good running 4.0, 4.56 would be as far as I would go, 4.88 are going to kill your mpg on highway and run your rpm very high to keep up with freeway traffic.

YJ fanatic 09-16-2013 10:55 AM

4.10s were perfect in my jeep when I had 33s. I had the 4.0 5 speed. 4.88s would have been terrible anywhere but the trail.

wasomma 09-16-2013 10:59 AM

Tire & Gear Ratio Chart at Morris 4x4 Center

BCDonny 09-16-2013 11:10 AM

I myself thinking 4.56 for me 4.2 5 speed 33 inch rubber

Signalman 09-16-2013 11:43 AM

Thanks but has anyone actually used this combo?

landscapetree0 09-16-2013 07:25 PM

I have i6 with 4.56 and 33. Not good on highway but mine is just for trail.

harleydragon 09-16-2013 07:35 PM

4.88 with 33's is too low for the road

Teague242 09-16-2013 07:39 PM

Quote:

Originally Posted by Signalman (Post 4615433)
Thanks but has anyone actually used this combo?

X2

My jeep is getting 4.88s and 33s in a few months.

I want to know what speed it will cruise at in 5th.

O_M_Jeep 09-16-2013 07:48 PM

I run 4.88's and 33"s with the 2.5 & AX-5, with the 4.0 4.10s should be really good, I had 4.10s stock and off-road they were perfect, but on road and driving the 4.10s with the 33"s didnt allow for uphill travel or keeping speed.

SickBoys95YJ 09-16-2013 09:17 PM

Quote:

Originally Posted by O_M_Jeep (Post 4627177)
I run 4.88's and 33"s with the 2.5 & AX-5, with the 4.0 4.10s should be really good, I had 4.10s stock and off-road they were perfect, but on road and driving the 4.10s with the 33"s didnt allow for uphill travel or keeping speed.


I'm turning 33's with 4.56's on my 2.5/AX5 combo. Excellent on the trail and 16-19 MPG if I'm not gas-assing around.


Sick

Yeahbuddy 09-16-2013 09:27 PM

I also have 33 /12.5s with a 2.5L and 4.88s...and a 5 speed. gets around good in town for city driving its all about planning your shifts. Higher rpm than I'd like for highway speeds on a regular basis. It is deffanitly at home crawling around on the trail.

c5wagner 09-16-2013 10:58 PM

My bro's offroad only cherokee has the 4.0l, 4.88's, and 33's and his top speed on the freeway is 50mph at 3500rpm's(not good to do)

Jeep_Monkey 09-16-2013 10:59 PM

My rig:
  • 2.5L - 4 cylinder engine
  • 5-speed AX-5 transmission
  • 32x10.5" BFG AT tires
  • 4.56 ratio differentials
When looking at trying to balance differential gear ratios and tire size, you have to decide which parameter is most important to you.

1. Low-end torque (ability to climb trees and rocks)
2. Acceleration (ability to leap into interstate traffic)
3. High-end power (ability to climb hills at highway speeds)
4. Gas mileage (ability to go farther and operate cheaply)

Playing this game is like squeezing a balloon... you tighten down in one place but it blows up somewhere else.

My journey started out when I decided my jeep would look better with bigger tires. The jeep started with the original size tires (about 27" dia). The existing tires were over 10 years old and had cracks in the sidewalls, so it was time for new tires anyway. So I invested in a 5 new rims and 5 brand new BFG 32x10.5" tires (the spare was original).

The Jeep still rode rough, and the tires would rub the fender wells every now and then because it needed shocks and the springs had sagged. So I invested in a 4" lift. That was a major improvement in comfort of ride.

However, I drove the Jeep to visit family in Mississippi and could really tell the difference in how it performed on the highway. I got 12-13 mpg trying to drive 60 - 65 mph on the interstate. Almost any uphill grade or headwind would force me to drop out of 5th gear just to try maintaining speed. I was contemplating going back to small tires.

As you have seen people do on here, the answer I got was re-gear. So I did my research and decided to re-gear to 4.56 ratio. I am still weak on the high-end power, but not as bad as I was before re-gearing. Mileage actually improved to around 18 mpg driving around 65 mph using low-ethanol fuel.

Last year, when I went on vacation in Colorado, I was only able to go 20-30 mph going uphill on the Million Dollar Highway. This year, I was in the 35-40 mph range. I suspect 4.88 ratio gears would improve this, but not sure how it will impact everything else.

As for RPMs, I pull somewhere around 2900 RPM in 5th gear at 70 mph. I estimate that I would be pulling around 3200 RPM with 4.88 gears. That is not too bad in itself... but I suspect I would be maxing out RPMs getting up to speed in the lower gears.

SickBoys95YJ 09-16-2013 11:31 PM

Jeep_Monkey hit the nail on the head. You'll need to decide what it is your YJ will be doing. My build was simple. I drive the Jeep when the weather in north Fla doesn't cooperate and the Harley stays in the garage. It also takes me where I want to hunt.

Bad Cornflakes 09-16-2013 11:42 PM

Don't do 4.88's with the 4.0 or the 4.2 if you plan to commute in your Jeep. 4.10's are plenty adequate with the 5 speed trans and 33" tires.

wasomma 09-17-2013 09:10 AM

Quote:

Originally Posted by Bad Cornflakes (Post 4634153)
Don't do 4.88's with the 4.0 or the 4.2 if you plan to commute in your Jeep. 4.10's are plenty adequate with the 5 speed trans and 33" tires.

Yea it really depends on what you want to do. Most people don't have 4.88s with 33s and the 4.0L unless it is strictly a trail rig. If you are gonna be going 35mph max then 4.88 is perfect. If you want to be able to drive on the highway, I wouldn't go for it.


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