What's new

Guidance - Axle width advice

CLSegraves1

Member
Joined
Jul 6, 2020
Member Number
2255
Messages
13
I'm in AZ (Phoenix) and could use some guidance as to whether or not narrowing an axle for my 2001 XJ if the right thing to do. This weekend I picked up a D60 out of a 05 Super Duty and my gut says narrow it, but I want input from people who know more than me.

I've been running 35s on the trussed HP D30 in my XJ for the past 3 years and it's performed very well. However, I'm in the final parts collection phase (odds and ends... already have the engine/adapters/wiring/etc.) of a LS1 swap and I want to move up to 37s or 38s. So I've outgrown the D30....

My rear axle is a trussed XJ D44 with 30 spline axles so I'm considering continuing to run it for a little while (or not... that's up in the air).


The listed values I find on the net are:

XJ D30 - WMS to WMS: 60 5/8"
SD D60 - WMS to WMS: 72"

I did a quick and dirty comparison of the D30 vs D60 width vs. pinion location. It looks like if I cut 8" off the passenger (long) side tube, that will both bring the axle down to 64" and get the pinion yoke into the D30/factory location. I currently run 3.5" backspaced 9.5" wheels. I have to buy new wheels anyways, so if I move to a 4.5" backspaced wheel I would be almost the same width as I am now. I plan to shave the center section to pick up/regain 1"-1.5" of ground clearance. I'm not concerned with the difficulty or cost of narrowing the axle. I'll be removing the inner Cs regardless in order to set the pinion/caster angle and it looks like I can have the axle shaft re-splined for $75-$100.

My question is purely one of "should I?" for performance reasons. I've always tried to keep my vehicle as low CG/compact as possible, but then I've never wheeled a wide axle vehicle before. I like to rock crawl and it's been my experience that where the wider JK/JL track width get hung up/have to work over things, the slightly narrower XJ track width gives me more lines to pick (I'm jealous of the samurai that sometimes goes with us and goes around everything
laugh2.gif
). BUT, I always hear people talking about the added stability afforded by wider axles.

So if I cut it down, what am I giving up?
 

'84 Bronco II

El Chingón
Joined
May 19, 2020
Member Number
293
Messages
1,240
Loc
NM
Stability, that is why you shouldn't narrow your axles. If you are worried about being too wide, run some stock wheels or wheels with close to stock offset. You can come in right around 80" outside tire to outside tire with stock wheels. If you are swapping in one tons, your rig should be capable of just driving over anything you can't fit between. If you lived in the PNW and had to squeeze between trees, my answer would be different, but AZ has essentially the same terrain NM does and I would never consider narrowing axles in a dedicated crawler. How many buggies do you see running narrow axles?

Don't waste your time running a Dana 44 rear with the Superduty 60 up front and grab a Sterling. I've posted my opinion on this before, but I think 37s are on the small side to run with one tons and I would suggest running 39"+ tires; the bone stock Superduty axles can handle it.
 

ArTi54N

YouTuber
Joined
May 26, 2020
Member Number
1511
Messages
1,146
Loc
Republic of the Rio Grande
wait.. so you only want to narrow it, in order for things to line up with how the previous axle fit??

Id say do the extra work, and not to narrow it..
 

CLSegraves1

Member
Joined
Jul 6, 2020
Member Number
2255
Messages
13
wait.. so you only want to narrow it, in order for things to line up with how the previous axle fit??

Id say do the extra work, and not to narrow it..


No, I'm inclined to narrow it because I was inclined to keep the track narrow (narrow track = get through tighter spots). I MAY continue to run the D44 for a while because I have it and it works. Eventually it WILL get replaced with a 10.5 (which if I narrow the 60 would also get narrowed).
 

Rangerrod

Well-known member
Joined
May 19, 2020
Member Number
264
Messages
229
I narrowed a 60 for similar reasons more streetable keep it narrower for tighter trails and so my suspension would line up better.

I wouldn’t do it again and I’m still at 65”. Artec sells a truss kit for that axle to make it a bolt in affair. as stated above the knuckles are just huge. So after you narrow there’s not a lot of axle tube left for suspension.

https://www.artecindustries.com/tjfd60swap
 

TRINDU

PBB Orphan
Joined
May 19, 2020
Member Number
386
Messages
2,472
Loc
Central TX
You're getting way ahead of yourself. Think a D44 rear is fine, but need a D60 front.

Soon as you put the cherocar on its side you'll have to scrap the tin can and start over.
 

arse_sidewards

Masshole
Joined
May 19, 2020
Member Number
71
Messages
4,340
Loc
Worcester County
Depends where you wheel. Full width stability is nice but even with stock offset wheels a stock width superduty axle is gonna have a hell of a time getting down trails that primarily see SxS and ATV traffic, which is most trails around here. Getting down to about the stock width of a midsize vehicle makes a huge difference IMO.

That said, I wouldn't narrow the front so much that it compromises turning radius. Being able to make tight turns is more important than being narrow.
 

'84 Bronco II

El Chingón
Joined
May 19, 2020
Member Number
293
Messages
1,240
Loc
NM
No, I'm inclined to narrow it because I was inclined to keep the track narrow (narrow track = get through tighter spots). I MAY continue to run the D44 for a while because I have it and it works. Eventually it WILL get replaced with a 10.5 (which if I narrow the 60 would also get narrowed).

What trails are you wheeling in AZ that you think being narrower will be a big advantage? The cost for wheel adapters alone will be about as much as you can pick a Sterling up for. Forget about that shitty XJ 44. You could probably sell it to some Jeep retard for enough to more than cover what the Sterling would cost you.

Going up in tire size, you may want the extra width just to keep the same turning radius. Wider track width lowers you CG without changing anything else.

Good point about clearance for the steer tires, but a wider track width doesn't "lower" your CG despite improving lateral stability. Now assuming that his ride height doesn't change, his CG may become lower because the one ton axles will add a bunch of weight down low.
 
Last edited:

Lil'John

Former #278
Joined
May 20, 2020
Member Number
488
Messages
915
Loc
Walking to the Rubicon
I don't care for the look of full width but depending upon tire size, you might need to go full width.

Here are two of the same rig:
notTwins1_sml.jpg
The green rig is narrowed to 60" WMS. This is 5" over stock for the rig. The tires are 35". The axle was a Dodge d60 so it started life with 67" WMS. The only work I needed to do was knock 7" off the driver side and weld a spring perch.

The brown rig is a full width Dodge d60 at 67" WMS. The tires are 43"x14.5". It is going to get linked. I don't overly care for the look but full width was needed to take advantage of 43s.

Both will be taken up the road to play on the Rubicon.
 

CLSegraves1

Member
Joined
Jul 6, 2020
Member Number
2255
Messages
13
I don't care for the look of full width but depending upon tire size, you might need to go full width.

The green rig is narrowed to 60" WMS. This is 5" over stock for the rig. The tires are 35". The axle was a Dodge d60 so it started life with 67" WMS. The only work I needed to do was knock 7" off the driver side and weld a spring perch.

The brown rig is a full width Dodge d60 at 67" WMS. The tires are 43"x14.5". It is going to get linked. I don't overly care for the look but full width was needed to take advantage of 43s.

Both will be taken up the road to play on the Rubicon.

What you did to the green rig's axle is the same thing I was contemplating doing to my axle. If you were building the green rig again, would you still cut or stay full width?



It seems there's some confusion as to how I was going to be narrowing the axle. I wouldn't be taking anything off the short side, only the long side (see attached picture/photoshop explanation).

So nothing changes on the driver's/short side. Both Artec and Barnes make a TJ truss for the super duty axle that I can use as-is if I stay full width. IF I narrow the long side, I can very easily chop a section out of the truss and graft it back together on the narrow width.


There also seems to be a misunderstanding regarding the D44. I'm NOT keeping it long term. Long term the rear is getting stretched (not a lot but enough to clear 37s on up travel) and the D44 would certainly get replaced at that time. The only reason I even mentioned keeping the D44 was IF I narrow the D60 then it "could" be used temporarily.


There are quite a few trails that I've run that are indeed side-by-side width trails. While the big rock crawling Jeep trails are wide, some of the trails run drop down into washes and get tight. It's not uncommon to be dragging dense brush right down the side of the vehicle.

photo12882.jpg


photo12883.jpg
 

'84 Bronco II

El Chingón
Joined
May 19, 2020
Member Number
293
Messages
1,240
Loc
NM
There are quite a few trails that I've run that are indeed side-by-side width trails. While the big rock crawling Jeep trails are wide, some of the trails run drop down into washes and get tight. It's not uncommon to be dragging dense brush right down the side of the vehicle.

Your tires aren't going to care about some bushwacking.

Measure how wide your Jeep is currently outside tire to outside tire. It looks pretty wide with the low backspacing wheels you are running now. My Superduty with 285s on stock wheels measures 78-79" outside tire to outside tire, and my beater Bronco II with '79 F250 axles (69" WMS front) and stockish offset wheels and 325s is under 80" I am pretty sure. My point is that with the right wheels, you shouldn't be a whole lot wider than you are now, and you can save time and money from having to narrow your axles. Additionally, if you ever decide to go wider, you are just a set of wheels or spacers away.

Here is the difference between 59" WMS with 3.75" back spaced 8" wheels and 12.50" tires and 69" WMS with 7" wheels and 4" backspacing and 325 (~12.75") tires:
fetch
 
Last edited:

CLSegraves1

Member
Joined
Jul 6, 2020
Member Number
2255
Messages
13
Your tires aren't going to care about some bushwacking.

Measure how wide your Jeep is currently outside tire to outside tire. It looks pretty wide with the low backspacing wheels you are running now. My Superduty with 285s on stock wheels measures 78-79" outside tire to outside tire, and my beater Bronco II with '79 F250 axles (69" WMS front) and stockish offset wheels and 325s is under 80" I am pretty sure. My point is that with the right wheels, you shouldn't be a whole lot wider than you are now, and you can save time and money from having to narrow your axles. Additionally, if you ever decide to go wider, you are just a set of wheels or spacers away.

Thanks for the numbers. I'll grab a tape measure when I get home and have a look. My current backspacing is 3.5". I can get 4.5" in an off the shelf wheel or up to 6" if I have one built. But I may be just chasing something that really doesn't matter.
 

arse_sidewards

Masshole
Joined
May 19, 2020
Member Number
71
Messages
4,340
Loc
Worcester County
Here is the difference between 59" WMS with 3.75" back spaced 8" wheels and 12.50" tires and 69" WMS with 7" wheels and 4" backspacing and 325 (~12.75") tires:
fetch

While it might not matter out west having that extra couple inches of width, particularly at the rear would really screw you out east. I can't count how many times I've had to snake my way between trees and if the vehicle were any wider it simply wouldn't make it because I wouldn't be able to turn enough after getting the front half past the tree.
 

'84 Bronco II

El Chingón
Joined
May 19, 2020
Member Number
293
Messages
1,240
Loc
NM
While it might not matter out west having that extra couple inches of width, particularly at the rear would really screw you out east. I can't count how many times I've had to snake my way between trees and if the vehicle were any wider it simply wouldn't make it because I wouldn't be able to turn enough after getting the front half past the tree.

Like I said, he lives in Arizona, I live in New Mexico. The two states share extremely similar terrain. I can only really think of one specific obstacle that favors a narrower rig (still not that big of a deal full width, just a bit more difficult), but 99% of the time I would rather have full width axles. The confidence the extra stability provides is worth it especially on the hard stuff. I already mentioned that if you are somewhere where trees are an issue, then narrowing might be a good idea, but in the southwest, full width is the way to go :grinpimp:
 

CLSegraves1

Member
Joined
Jul 6, 2020
Member Number
2255
Messages
13
While it might not matter out west having that extra couple inches of width, particularly at the rear would really screw you out east. I can't count how many times I've had to snake my way between trees and if the vehicle were any wider it simply wouldn't make it because I wouldn't be able to turn enough after getting the front half past the tree.

That brings to mind a different question. What about a wide front axle and narrow rear? It's not typical on road vehicles but I've seen quite a few purpose built rigs that had somewhat wider front than rear.


Like I said, he lives in Arizona, I live in New Mexico. The two states share extremely similar terrain. I can only really think of one specific obstacle that favors a narrower rig (still not that big of a deal full width, just a bit more difficult), but 99% of the time I would rather have full width axles. The confidence the extra stability provides is worth it especially on the hard stuff. I already mentioned that if you are somewhere where trees are an issue, then narrowing might be a good idea, but in the southwest, full width is the way to go :grinpimp:

Would you go full width with low inset (3.5" or 4.5") or full width with higher inset (6")?
 

Lil'John

Former #278
Joined
May 20, 2020
Member Number
488
Messages
915
Loc
Walking to the Rubicon
What you did to the green rig's axle is the same thing I was contemplating doing to my axle. If you were building the green rig again, would you still cut or stay full width?

I would absolutely do the same thing. In my case, it is 'cheaper' to go this route over outboarding springs and linking. Do you have to buy new axle shafts? Sure. But if you were already planning on upgrading the shafts the "custom" length is a non-issue.

I have a third FJ55 in progress. Originally, I was going to do the same build pattern as the green one... I had the rear narrowed up(Ford e350 van Dana 60) I then ended up with a full width dodge that was driver offset. The build plan changed to go full width and rear steer.

That narrowed rear axle will end up in an FJ40 project. It will get a narrowed dodge d60.
 

'84 Bronco II

El Chingón
Joined
May 19, 2020
Member Number
293
Messages
1,240
Loc
NM
That brings to mind a different question. What about a wide front axle and narrow rear? It's not typical on road vehicles but I've seen quite a few purpose built rigs that had somewhat wider front than rear.




Would you go full width with low inset (3.5" or 4.5") or full width with higher inset (6")?

Depends. With close to stock offset wheels and ~80" outside tire to outside tire, I can load up on my standard car hauler without having drive over fenders which is nice. However, for all out performance in the rocks, being a bit wider is nice. I think being in the mid 80s range would be ideal personally.
 

CLSegraves1

Member
Joined
Jul 6, 2020
Member Number
2255
Messages
13
I would absolutely do the same thing. In my case, it is 'cheaper' to go this route over outboarding springs and linking. Do you have to buy new axle shafts? Sure. But if you were already planning on upgrading the shafts the "custom" length is a non-issue.

I have a third FJ55 in progress. Originally, I was going to do the same build pattern as the green one... I had the rear narrowed up(Ford e350 van Dana 60) I then ended up with a full width dodge that was driver offset. The build plan changed to go full width and rear steer.

That narrowed rear axle will end up in an FJ40 project. It will get a narrowed dodge d60.

So in your case there were also packaging considerations.

Assume that the packaging (out-boarding springs and links) hadn't been a consideration, would that have changed your decision?
 

Lil'John

Former #278
Joined
May 20, 2020
Member Number
488
Messages
915
Loc
Walking to the Rubicon
Would you go full width with low inset (3.5" or 4.5") or full width with higher inset (6")?
For what it is worth, the brown cruiser is ~4.5" backspacing(17x9 rim)

So in your case there were also packaging considerations.

Assume that the packaging (out-boarding springs and links) hadn't been a consideration, would that have changed your decision?
In all honesty, packaging had zero impact on why I went narrow. I just really dislike the look of 3"+ of tires hanging outside the body. The green cruiser has around 1" of tire out. The brown cruiser has 7" of tire hanging out.
 

CLSegraves1

Member
Joined
Jul 6, 2020
Member Number
2255
Messages
13
Depends. With close to stock offset wheels and ~80" outside tire to outside tire, I can load up on my standard car hauler without having drive over fenders which is nice. However, for all out performance in the rocks, being a bit wider is nice. I think being in the mid 80s range would be ideal personally.

Well just on the surface (D60 math):
- 72" WMS axle width
- 9" rim with 4.5" inset
- 12.5" wide tire

I would be 84.5" outside to outside.


By comparison (D30 math):
- 60.625" WMS axle width
- 9" rim with 3.5" inset
- 12.5" wide tire

Says I'm currently at 75.125" outside to outside.

So I'd pick up 9.375" of outside tire width on a the D60. If I had 6" inset wheels made, that would bring it down to 81.5", which is pretty close to your 80" target.

What's better, the 81.5" or the 84.5"?
 
Last edited:

'84 Bronco II

El Chingón
Joined
May 19, 2020
Member Number
293
Messages
1,240
Loc
NM
Well just on the surface (D60 math):
- 72" WMS axle width
- 9" rim with 4.5" inset
- 12.5" wide tire

I would be 84.5" outside to outside.


By comparison (D30 math):
- 60.625" WMS axle width
- 9" rim with 3.5" inset
- 12.5" wide tire

Says I'm currently at 75.125" outside to outside.

So I'd pick up 9.375" of outside tire width on a the D60. If I had 6" inset wheels made, that would bring it down to 81.5", which is pretty close to your 80" target.

What's better, the 81.5" or the 84.5"?

So I went outside and did some measuring on my junk.

My car hauler is 81.25" between the fenders, which I think is pretty typical. You can get a flat deck trailer or build drive over fenders to accommodate a wider rig, both of which have their pros and cons, but that is something to consider when you are deciding how wide to go.

My brown Bronco II
-59.5" WMS width
-8" wheel, 3.75" backspace
-12.5" wide tires

I measured 73.5" not at the sidewall bulge. -You need to keep in mind that backspace is measured from the outside of the wheel lip, not the inside bead mounting surface, so you'll be a bit wider than what you calculated.

The other Bronco II is at my grandfather's farm right now, but it barely fits on my car hauler, so it must be right around 80" as I was guessing earlier.

I have a set of 2007 F250 axles with the factory 8 hole Alcoas mounted with 285 tires and they measure right at 78" outside tire to outside tire, so with factory wheels, you would only be ~4" wider than you are now.

Like I said before, from a performance standpoint I think ~85" is where you want to be, but from a fitting on a standard car hauler and not being too much wider than you are now, it is possible to come in at or under 80" using factory style offset wheels without narrowing the axle.
 

YotaAtieToo

Thick skull
Joined
May 19, 2020
Member Number
142
Messages
6,552
Loc
Bonners Ferry, ID
One nice thing about the 05+ is the hub doesn't stick out very far so you can run deep back spacing.

I think some of the stock 17s were 5"+ bs

Don't narrow it 8" that's dumb, almost every person I've seen with narrowed axles hates them, or runs 3.5" or less back spacing. If you insist on going narrower, do like 5"

Also don't waste time swapping the front and not the rear, wait a little longer and do it all at once.
 

I Lean

skull
Joined
May 19, 2020
Member Number
28
Messages
103
Loc
Magna, UT
Don't narrow it 8" that's dumb, almost every person I've seen with narrowed axles hates them, or runs 3.5" or less back spacing.

..or they end up adding wheel spacers to their build eventually.


If you insist on going narrower, do like 5"

Also don't waste time swapping the front and not the rear, wait a little longer and do it all at once.

Also agree with both of the above advice. If you have to narrow it, do it so you can run a different year stock-size axle shaft. That will make sourcing a shaft, and any future replacements, easier/cheaper than a custom length.
 

CLSegraves1

Member
Joined
Jul 6, 2020
Member Number
2255
Messages
13
One nice thing about the 05+ is the hub doesn't stick out very far so you can run deep back spacing.

I think some of the stock 17s were 5"+ bs

Don't narrow it 8" that's dumb, almost every person I've seen with narrowed axles hates them, or runs 3.5" or less back spacing. If you insist on going narrower, do like 5"


Yeah, the stock 17s are a high back spacing, but unfortunately they are only 7-1/2" wide. A 7-1/2" rim is pretty narrow for a 12.5" or 13.5" tire.
 

CLSegraves1

Member
Joined
Jul 6, 2020
Member Number
2255
Messages
13
If you have to narrow it, do it so you can run a different year stock-size axle shaft. That will make sourcing a shaft, and any future replacements, easier/cheaper than a custom length.

I'll have to look into that. I think the 99-04 is still a 35 spline inner shaft but I'm not sure what length it is or what u-joints it uses/if it would work with the 05+ outer shaft.
 

Hyde

Andgoseek
Joined
May 26, 2020
Member Number
1468
Messages
160
Loc
North Idaho
I would leave it full width, I spent last weekend wheeling through pretty tight trees in the PNW and never wished I was narrower. When we got to the rocks I was glad I had the width. With what I have pictured in my head of the Southwest I think your answer should be obvious.
FB_IMG_1594083032782.jpg
 

YotaAtieToo

Thick skull
Joined
May 19, 2020
Member Number
142
Messages
6,552
Loc
Bonners Ferry, ID
Yeah, the stock 17s are a high back spacing, but unfortunately they are only 7-1/2" wide. A 7-1/2" rim is pretty narrow for a 12.5" or 13.5" tire.

Not in my opinion. I've ran a bunch of 12.5s on 8" wide wheels. Can always add weld on beadlocks for ~9" wheel.

I have 42x14.5s on 8.5" wide wheels in my garage. And they're fine.

I'll have to look into that. I think the 99-04 is still a 35 spline inner shaft but I'm not sure what length it is or what u-joints it uses/if it would work with the 05+ outer shaft.

They should all be 1480 joints. Basically any front 60 shafts should work.
 
Top