CJ: Once lifted, how wide should axels be?

[headhunter]

All of the threads about how Chuck's Jeep does tricks all the time has me thinking about this!

What is the wisdom about how wide my axels should be if I go with a Rubicon Express 4.5" lift, a 1" body lift and 35" tires?

I figure that if I add these things together, 4.5" + 1" + 3" (half of the increase from 29" to 35" tires), I wind up with the Jeep 8.5" higher than it is now. That's if you don't take into account going from old sagging springs to new perky springs.

Since I have an '81 Scramber, it has the narrow track axels on it now. I think that they are 57" or 58", but don't remember for sure. Intuitively, I know I'll want to go wider as I go higher, but I'm guessing I don't need to increase width proportionately and wind up with 64" or 65" axels. Of course, I could be wrong and that's why I'm asking!

Is there a basic calculation that you use?

Thanks!

Christian

[dirtman13]

All of the threads about how Chuck's Jeep does tricks all the time has me thinking about this!

What is the wisdom about how wide my axels should be if I go with a Rubicon Express 4.5" lift, a 1" body lift and 35" tires?

I figure that if I add these things together, 4.5" + 1" + 3" (half of the increase from 29" to 35" tires), I wind up with the Jeep 8.5" higher than it is now. That's if you don't take into account going from old sagging springs to new perky springs.

Since I have an '81 Scramber, it has the narrow track axels on it now. I think that they are 57" or 58", but don't remember for sure. Intuitively, I know I'll want to go wider as I go higher, but I'm guessing I don't need to increase width proportionately and wind up with 64" or 65" axels. Of course, I could be wrong and that's why I'm asking!

Is there a basic calculation that you use?

Thanks!

Christian

That's a good question. I don't know of any formulas but I can tell you that my set up is to narrow (even with the spacers). I have the exact set up your thinking of getting.

The next thing on my list is to go to Dana 60's. I like the height I have but not the narrow stance. If I could some how extend the width of my current axles I would. I like them, have had no issues, and already have lockers. The only reason I'm going to 60's is because of the width.

Why not just go to 44's since they are easier to get? Because I believe that my well built axles are stronger then 44's and I don't want to loose the strength.:2:

[Double AA]

You didn't mention lockers so you're probably not planning on getting too crazy. Even so, you'll want as to add as much width as possible to your narrow track axles. You'll need a good set of wheel spacers, and 8-10" wheels with plenty of offset. You should be able to add at least 6" to your present width. The longer wheelbase of the Scrambler will also help.

That's about all you can do without changing out your axles. 35" tires are a good size tire and as long as you don't get too hardcore, your axle shafts and u joints should last for a reasonable amount of time.

[headhunter]

You didn't mention lockers so you're probably not planning on getting too crazy. Even so, you'll want as to add as much width as possible to your narrow track axles. You'll need a good set of wheel spacers, and 8-10" wheels with plenty of offset. You should be able to add at least 6" to your present width. The longer wheelbase of the Scrambler will also help.

That's about all you can do without changing out your axles. 35" tires are a good size tire and as long as you don't get too hardcore, your axle shafts and u joints should last for a reasonable amount of time.

I'm actually planning on lockers front and rear, but don't anticipate getting really crazy like some others I've seen.

I am thinking of either changing out my axels or beefing up the ones I have, so I'll be able to pick my width at that time. I may use spacers and offset wheels as an interim solution or I may just wait to have the cash to do it all at once.

Thanks.

Christian

[Double AA]

You're now at the crossroads. If you plan on installing gears and lockers, you'll also want cm shafts and good quality u joints. That will be around $3k. Next you'll need Crane or Dedenbear knuckles. When you brake a knuckle you're either SOL or extremely SOL. Also you'll need heavier steering components. The knuckles and steering will be an additional $1k.

So now you have $4k invested in narrow track AMC axles that are not up to the task. And if you ever decide you want to play in the serious rocks the shafts are too small and the housings are too week.

My recommendations for playing in the rocks are:
35" tires - D44 or Ford 8.8 min.
37"-40" tires D60
40"-44" tires 609's or aftermarket D60's

The lockers, gears and shafts will cost a little more for the bigger axles but you wont have to pay for the knuckles or steering.

Unless you find someone taking them out of a CJ the axles will need shortening. Also you'll be able to set the axles to the length and height of the tire you want to run.

I ran a D44 front and a D60 rear for years. The front axle broke u joints and shafts like candy. I also broke two knuckles on the Outer Limits trail at the hammers. The fortunate side was I had some good friend that stay and helped me though the entire day and then into the following morning. The unfortunate part was that now I owe them the same.

The D60 is dead reliable but on 37" tires it's like a frog ass, every time you move it hit the ground.

Figure out what your most extreme use will be, and use that as a guide when picking your components.

[headhunter]

You're now at the crossroads. If you plan on installing gears and lockers, you'll also want cm shafts and good quality u joints. That will be around $3k. Next you'll need Crane or Dedenbear knuckles. When you brake a knuckle you're either SOL or extremely SOL. Also you'll need heavier steering components. The knuckles and steering will be an additional $1k.

So now you have $4k invested in narrow track AMC axles that are not up to the task. And if you ever decide you want to play in the serious rocks the shafts are too small and the housings are too week.

My recommendations for playing in the rocks are:
35" tires - D44 or Ford 8.8 min.
37"-40" tires D60
40"-44" tires 609's or aftermarket D60's

The lockers, gears and shafts will cost a little more for the bigger axles but you wont have to pay for the knuckles or steering.

Unless you find someone taking them out of a CJ the axles will need shortening. Also you'll be able to set the axles to the length and height of the tire you want to run.

I ran a D44 front and a D60 rear for years. The front axle broke u joints and shafts like candy. I also broke two knuckles on the Outer Limits trail at the hammers. The fortunate side was I had some good friend that stay and helped me though the entire day and then into the following morning. The unfortunate part was that now I owe them the same.

The D60 is dead reliable but on 37" tires it's like a frog ass, every time you move it hit the ground.

Figure out what your most extreme use will be, and use that as a guide when picking your components.

This is really helpful info and goes right to the core of what I'm trying to figure out. I'd rather spend less money in the long run, by spending more money now on components that will be up to the task. It may take longer to get there, but I think I'll be happier for waiting and building a little slower.

Thanks!

Christian

[ECV Jeep]

As I am going through this conversion myself I can tell you what I know. With 60 inch wide axles you can get full turning (lock to lock) with 37 inch tires. If you want to run 40's or 4-link your CJ you should run axles at a minimum of roughly 62 inches.

At 60 inches wide, a CJ with as much lift as you have will feel unstable (better than stock, but not great). I ran mine that way for a time, but decided I like the 62.5 inch option best. I have also moved the front axle forward aboout 2 inches and the rear back just over 4 inches. All this has helped for stability. Currently the Jeep is SOA, but I am still moving towards a 4-link set-up. It does perform pretty well the way it is.

[headhunter]

As I am going through this conversion myself I can tell you what I know. With 60 inch wide axles you can get full turning (lock to lock) with 37 inch tires. If you want to run 40's or 4-link your CJ you should run axles at a minimum of roughly 62 inches.

At 60 inches wide, a CJ with as much lift as you have will feel unstable (better than stock, but not great). I ran mine that way for a time, but decided I like the 62.5 inch option best. I have also moved the front axle forward aboout 2 inches and the rear back just over 4 inches. All this has helped for stability. Currently the Jeep is SOA, but I am still moving towards a 4-link set-up. It does perform pretty well the way it is.

This is helpful info.

I think that I'll be fine front to back, since I have a Scrambler and my wheelbase is already 104".

It sounds like I shouldn't consider going less than 62 inches even though I don't think I'll ever wind up on 40-inch tires. I think I'll max out at 35-inch tires.

Once I decide exactly what I need to do, I can make a plan.

Thanks!

Christian

[ECV Jeep]

You are welcome. 62 inches would be a great width for your Scrambler. I think you would be well served to continue to solicit advise and then decide what is best for your needs. I sure wish I had done that to begin with....it would have save me time and money.

[headhunter]

I just found out that the narrow track axels on the my '81 Scrambler are probably a lot more narrow than I thought.

Someone from the SoCal Scramblers let me know that they are around 52" wide.

If this is what Chuck has, it's no wonder that he's flopping around so often.

So, if I went to 62" I'd be going up by 10"! I'd be going wider than my 8.5" increase in height, which I believe would increase my stability from my stock set up.

I may still be missing something, but I think I'm getting closer to a proper understanding.

Christian

[ECV Jeep]

On an 81 Scrambler, I believe your axle widths are 51.5" front and 50" rear. My 86 CJ was "wide track" so it was 55.8" front and 55" rear. At that width it was way tippy on 35s with an SOA set-up. Think about a modern TJ which has axles in the 60.5" range or the new JKs which are in the 62.9" range. 62 inches wide may sound like a lot, but it is a good set-up. Lots of CJ and YJ folks build axles at 60.5" for SOA applications. You only need to go wider if you are ever going to 4-link.

[headhunter]

On an 81 Scrambler, I believe your axle widths are 51.5" front and 50" rear. My 86 CJ was "wide track" so it was 55.8" front and 55" rear. At that width it was way tippy on 35s with an SOA set-up. Think about a modern TJ which has axles in the 60.5" range or the new JKs which are in the 62.9" range. 62 inches wide may sound like a lot, but it is a good set-up. Lots of CJ and YJ folks build axles at 60.5" for SOA applications. You only need to go wider if you are ever going to 4-link.

Thanks, again!

Being the kind of guy that likes to keep options open...how wide to you go if you decide to 4-link?

Going with a 4-link may be something to do way down the roard after everything else is in place. For now, it would cause me to hold off for too long on everything else.

Christian

[Double AA]

The short answer to how wide you need to go for a link suspension is it depends on a lot of factors. some of which are;
Tire size
Rim width and offset
Make of axles
The amount of steering angle you want to achieve
Are you running coil-overs, if so, what is the body diameter
Total shock travel
The amount of compression/droop
The type of front fenders you're willing to run
Frame modifications
How much tire your willing to have outside your fender flares

You need to get enough experience to have an idea of what you really want, and then come up with a plan. But be forewarned, your wants will continue to change. I don't know anyone that will say their Jeep is finished.

Installing a link suspension on a CJ and having it work properly is a real undertaking. You're going to want someone with experience to perform the work and it will be pricey.

Leaf springs, when done properly can perform really well. The problem is most of the lift kits are budget oriented and aimed at providing lift for larger tires, not offroad performance. Talk to one of the better, more experienced shops around and they can order and install, longer high quality springs from companies like National Spring.

If you install 35" tires and don't replace your differentials or re-gear, your Jeep will hate life on the road when leaving from a stop or driving at highway speeds. Personally I don't think re-gearing or adding lockers to your narrow track AMC differentials is worthwhile.

Just my 2 cents.

[headhunter]

The short answer to how wide you need to go for a link suspension is it depends on a lot of factors some of which are;
Tire size
Rim width and offset
Make of axles
The amount of steering you want to achieve
If you run coil-overs, and if so, their diameter?
Total shock travel
The amount of compression/droop
The type of front fenders you're willing to run
Frame modifications
How much tire your willing to have outside your fender flares

You need to get enough experience to have an idea of what you really want, and then come up with a plan. But be forewarned, your wants will continue to change. I don't know anyone that will say their Jeep is finished.

Installing a link suspension on a CJ and having it work properly is a real undertaking. You're going to want someone with experience to perform the work and it will be pricey.

Leaf springs, when done properly, can perform really well. The problem is most of the lift kits are budget oriented and aimed at providing lift for larger tires, not offroad performance. Talk to one of the better, more experienced shops around and they can order and install, longer higher quality springs from companies like National Spring.

If you install 35" tires and don't replace your differentials or re-gear, your Jeep will hate life on the road when leaving from a stop or at highway speeds. Personally I don't think re-gearing or adding lockers to your narrow track AMC differentials is worthwhile.

Just my 2 cents.

This all makes sense to me. I'm going to try to do things that won't "break the bank," but that will serve me well.

I tend to think that putting money into the narrow tracks would be a bit of a waste and that I'd do better spending that money on something else. It looks like putting band-aids on both axels will cost about as much as doing one axel properly.

I already plan to replace my transmission. I've got an SR-4 which is known to be weak. I think I want to go with an Muncie SM420 for its low 1st gear (7.05). I don't think I'll really mind that it "drives like a truck transmission" as many people put it. That said, I'd like to drive one before I make that decision.

That would be one step toward lower gearing. I think I'd like to either stay with 4.10 gears in the axels or maybe go to 4.56. I don't think I want to go to 4.88. If I felt I needed a lower gear, I'd probably do it with the transfer case instead.

Those are some of my thoughts about where I want to take this. I'm sure some of my ideas will change along the way.

I'm in no hurry and just plan to run trails that are appropriate to whatever capabilities I have with my Jeep and my driving skills along the way. I like the journey and am not to concerned about getting to the destination quickly. It's going to take time to build the skill I'll need when I get the rig built.

The only time limit I have is that I have to either go to fuel injection or hook up the rest of my smog equipment with my carburetor before next March when I have to pass smog again.

Thanks again.

Christian

[Double AA]

The SM420 is a great trany if you don't need over drive. The T18 and T98 are also good choices for not having OD. I went with a NV4500 which also shifts like a big truck trans.

If you're interested in a Howell fuel injection I have one complete with fuel pump and installation instructions. It was on my 258 when I pulled it. PM me if you're interested.