Best axles/gearing for on/off road CJ-7

[gre123]

I'm looking for advice on what size axles and gearing I should get if I want to be able to go trail riding and a little off roading, then be able to drive it home. Suggestions are much appreciated, thanks!

 

[TnCJ]

What size tires are you running?

 

[gre123]

I’d like to run 35s, an all terrain, not too aggressive lugs

 

[Lumpy Grits]

Ford 9" in the rear with 4:88 R&P is a good start.
4-1 t'case conversion helps.
You gonna run LSD or real lockers in the diffs?
What are you run'n for a trany?
For what you describe for your usage, 33's would work just fine for tires.
Gary

 

[jfmcj7]

I run 35" with the 3 speed auto with 4:56 gears and run about 3300rpm at 70mph witch I don't like. At 55 mph it is just under 3000 rpm witch feels better for the engine.

 

[Lumpy Grits]

I run 35" with the 3 speed auto with 4:56 gears and run about 3300rpm at 70mph witch I don't like. At 55 mph it is just under 3000 rpm witch feels better for the engine.

Ck your speedo or tachometer as something is off.
Gary

 

[gre123]

Ford 9" in the rear with 4:88 R&P is a good start.
4-1 t'case conversion helps.
You gonna run LSD or real lockers in the diffs?
What are you run'n for a trany?
For what you describe for your usage, 33's would work just fine for tires.
Gary

Would it be a pain on roads with real lockers?

 

[Lumpy Grits]

My CJ is a daily driver.
There's a few quarks you'll have to get use to.
Gary

 

[Flundertaker]

Depends on trans and engine.
I have 31’s on my 86 with 3.31 and a T5. Tires probably change the effective ratio to about 3:1. If I stepped up to 33 or 35 I woukd definetly regear but my 258 has plenty of low end and doesn’t like 3000+ rpms. I keep it under 2000 rpms almost exclusively. I can cruise on the highway between 55-60 and stay under 2k. I have no desire to drive any faster in it.


Sent from my iPhone using Tapatalk

 

[Lumpy Grits]

Depends on trans and engine.
I have 31’s on my 86 with 3.31 and a T5. Tires probably change the effective ratio to about 3:1. If I stepped up to 33 or 35 I woukd definetly regear but my 258 has plenty of low end and doesn’t like 3000+ rpms. I keep it under 2000 rpms almost exclusively. I can cruise on the highway between 55-60 and stay under 2k. I have no desire to drive any faster in it.


Sent from my iPhone using Tapatalk

Under 2k rpm, you're lugging that engine.
You want 2300-2500rpm at cruise speed.
Gary

 

[jfmcj7]

Speedo is accurate according gps. The tach, who knows, but I can here the engine scream.

Ck your speedo or tachometer as something is off.
Gary

 

[Lumpy Grits]

Speedo is accurate according gps. The tach, who knows, but I can here the engine scream.

258's aren't quiet
Gary

 

[HackFabrication]

I'm looking for advice on what size axles and gearing I should get if I want to be able to go trail riding and a little off roading, then be able to drive it home. Suggestions are much appreciated, thanks!

Since you plan on running 35" tires, and I'm assuming you have a 4 speed trans (no overdrive) or 3spd auto, you would be best suited to go with a 4.56 ratio. You could do a 4.88, but keep in mind that the stock front Dana 30 will have a very small pinion gear. The axle already has it's weaknesses, and you'll be at the limits with 35" tires, IMHO.

Lockers are what you want to spend. I'm running ARB front/rear. I wanted a conventional rear differential for street/pavement use. But I have a shorter CJ5.

Personally, I'd rather see 33's and 4.11 gears on a street/trail CJ. You can get by with a lower lift on 33's, unless you are really going to articulate (rocks, stumps, logs, ditches, etc.) the suspension. Plus different tires, measure different. 35" tires will need a 4" lift, which may bring with it a number of other 'issues' that you may find worrisome. Especially if you have a narrow track set of axles, where you will be moving the center of gravity up.

My 76 CJ5 has a Ford Racing 5.0L, T18 transmission, Dana 20 T-case (TerLow'd), and 4.56 gearing. I'm running 32" tires (2.5" BDS lift), which are not a true 32" diameter. I can run at interstate speeds, 70-80mph, but I don't want to. Short wheelbase, narrow axles, and all the aerodynamics of a cinder block add up to additional vigilance when speeds go above 60mph. I'm perfectly happy running at 55-60 mph.