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Wider front axle

21K views 236 replies 13 participants last post by  paulsheer2 
#1 ·
In order to get a wider stance, I previously put on wheels with an obnoxious offset.

But I'd rather have a setup where the contact patch is over the ball-joint axis -- which would give the best road feel, no?

(My front axle is now leaking near the right-side drive shaft, and since the front axle is the only thing I have not overhauled, I thought I would do this next and widen it at the same time.)

Now I might cut the axle and lengthen the tubes. This seems like a complicated job. Probably don't want this.

--

Here are my questions please:

1. What are options for longer left and right rzeppa drive shafts assuming I go ahead and lengthen the axle tubes?
2. What is the stock width (mounting-surface to mount-surface) of the ZJ D30?
3. What axle swap options would net me a good 6 inches wider front wheel base??? (i.e. push out the hub mating point 3 inches on each side?)
4. Are there tables of front axle widths anywhere? (I can find none, and I've looked quite hard.)

(fyi, i'll keep 3.73)
 
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#2 ·
1) Custom RCV's, unless you go with a WJ D30.
2) Stock d30 is 60.5 wms-wms.
3) A ford HP44 with 5 lug outers is about 65" wms-wms, that's about as close to your 6" number as you're likely to get. The WJ is 63.5" which would get you something that you can easily swap into the jeep. The full size actors with 8 lug outers end up at 69" wms-wms.
4) No, not really.

What obnoxious backspace are you running? At your height widening the track width isn't gonna buy you much in terms of stability unless you're running something very weird.
 
#3 ·
Your best bet for wider axles would be a matching set of front and rear axles from a JK. There are no bolt-on axles with wider track width available, so it's gonna be part custom job anyways - unless you go with something like Dynatrack setting you up the axle

You are absolutely correct about the scrub radius, you'd optimally want to avoid wheels with way less backspacing than OEM. It causes all sorts of drivebility issues and other side-effect both on road and off road.
 
#5 ·
Thanks,

I'm finding there is no way to get Rzeppa CV joints axles shafts on anything except a Dana 30.
....ok, there are some ridiculously expensive aftermarket Rzeppa joints, but nothing stock.

Can I assume that everyone doing a D44 or D60 axle swap is using U-joints?
Are people happy with U-joints?
Any other ideas?

Otherwise I *think* I have a solution:

Step 1 is to buy this:

http://www.synergymfg.com/Synergy-Jeep-TJ-LJ-XJ-ZJ-Front-Axle-Assurance-Kit-p-30950.html

Step 2 is to buy this donor, 45 minutes drive:

https://dallas.craigslist.org/dal/pts/6147348660.html

Then I'm going to cut the C bracket plus a few inches of axle off the donor. Then insert the tubes and weld.

Thoughts?

My final problem is making "something" to extend the inner shaft of the Rzeppa joint.

How can I do this? Custom inner shaft?
 
#6 ·
I'm finding there is no way to get Rzeppa CV joints axles shafts on anything except a Dana 30.
....ok, there are some ridiculously expensive aftermarket Rzeppa joints, but nothing stock.
The only CV- joint shafts worth buying for US- built axles are RCV shafts. They are about 1200-1400$ for a set - and they are about the best quality you can get.
Normal u-joint style alloy axle shafts are around 600-1000$ for a set, so RCVs aren't that expensive really if you keep in mind the quality of them.

Can I assume that everyone doing a D44 or D60 axle swap is using U-joints?
A lot of people use u-joint shafts, but there are plenty of people using RCVs as well. It's really up to you how much you want to invest.

Are people happy with U-joints?
U-joints are easy and simple, but CV- joints operate much smoother and are stronger when built right.

Stock- style CV shafts on the ZJs aren't built right and are not strong, OEM Spicer U-joint style axle shafts from TJs, ZJs or XJs (as long as they are the larger -260x/760x- syle) are significantly stronger than the OEM CVs are.

Inner axle sleeves are a waste of money IMO - either truss the axle or fab outer axle sleeves to increase outer diameter to 3" and wall thickness to 1/2";
* 3" OD x .250" wall DOM tube is stronger than 2.5" OD .500" wall DOM
* 3" OD x .500" wall DOM is almost twice as strong as 2.5" OD .500" wall DOM
* 3" OD x .500" wall DOM is well over twice as strong as 2.5" OD .250" wall DOM

OEM D30 tubes are 2.5" OD .250" wall.

As for getting to the width you're looking for, I'd suggest checking out different inner shaft lengths available. That way you can use readily available shafts at a good price to get the width and center housing location you want and need.

You really should press out the old tubes from the housing, and have new machined DOM tubes pressed in and butt- welded to the housing if you want to fab a custom- width axle. Or get a wide- track axle, and cut the tubes at the ends and re-weld the inner-Cs.
If you're going to cut the axle tubes, and then use pieces of tube to make the axle wider, you MUST use inner axle sleeves around the cut/ weld area to make the tube strong enough. I do not recommend this.
 
#7 ·
Thanks,

"different inner axle shafts"

Yes, but how/where do I find these?

I will use the inner sleeves for alignment... assuming they are a tight fit. But Ill also truss it.

Im actually eating at a diner right now while the Yard is pulling an axle from a scrap 5.9. $120.



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#8 ·
Thanks,

"different inner axle shafts"

Yes, but how/where do I find these?
There are about a gazillion different D44s that have been built during the past ~60 years, of which most mid-to-late-70s and newer have 30-spline inner shafts and the correct u-joints. There are plenty of charts available if you google.

Keep in mind using longer inner shafts require you to modify axle tube length.

I will use the inner sleeves for alignment... assuming they are a tight fit. But Ill also truss it.
They should be a tight fit.

Im actually eating at a diner right now while the Yard is pulling an axle from a scrap 5.9. $120.
Why a 5.9 axle? It gives you zero strength gains. If you're looking for a slightly better bolt-on front axle, you should look for a 90-99 XJ high pinion D30.

If you want a relatively easy stronger swap, a narrow-track Jeep Wagoneer low pinion D44 is the way to go. Then there are the Ford F150/F250/ early- Bronco high- pinion D44 front axles, of which some are good and some are not. If you just use the center housing and do all custom work, just about all Ford HP D44 housing are good.

Or, just get the JK front/ rear D44s from a JK Rubi and fab new brackets. It will give you about a 5" track width increase over the ZJ axles (ZJ/ TJ/XJ axles are ~60.5" WMS-WMS, JKs are slightly over 65" WMS-WMS).
 
#9 ·
My priority is CV not U. And then also not wanting to spend on those super-expensive CVs.

Are there cheep CVs available for the D44?

If not, then Im staying with the D30.

What are the unit bearing differences and spline differences between the D44 and D30.

The axle shafts are the usual point of failure no?


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#10 ·
Are there cheep CVs available for the D44?
Nope.

If not, then Im staying with the D30.
ZJ CVs are the only cheap ones you can find on the D30s. And they are weak..

What are the unit bearing differences and spline differences between the D44 and D30.
D30 uses 27-spline inner shafts, there are aftermarket 30-splines. Outers are 27-spline, there are 30-spline outers.
Traditional D44 front axles do not use unit bearings at all. It's really only JK Rubi front D44s that use unit bearings.
D44 inner shafts are 30-spline, and they match the upgraded D30 inner 30-spline shafts.

The axle shafts are the usual point of failure no?
On a stock LP D30 from a ZJ with CV shafts, the failure point in most cases is the short side inner shaft neckdown right before the CV joint - or the CV joint.
On a stock HP D30 using OEM U-joint shafts, it's often the axle shaft or R&P.
On a stock LP D30 with U-joint alloy shafts you're gonna kill the R&P
On a stock HP D30 with alloy shafts you're either gonna kill U-joints or R&P
 
#11 ·
WJ d30 is wider and uses CV joints.

Still weak.
 
#14 ·
#15 ·
The old style d44 is 5 1/2" from tube center to bottom of the pumpkin (or top). The d30 isn't much smaller, and people have no issues running the HP30's in lowered ZJ's.
 
#16 ·
I have Artec Coil-Brackets and LCA bracket and Artec C gussets in my cart.

Where do I get a ZJ passenger side Upper Control Arm tower?

Here is where I am leaning today ---

http://www.jeepforum.com/forum/f9/cryogenic-ring-pinion-axle-shafts-more-1429857/

You can get your ring and pinion gears cryogenically treated to make them almost as strong as a Dana 44.

All that remains is making longer inner shafts for the CV. This I can do on my lathe. I don't have the tools to do the splines. The splines will probably be $200 at a machine shop at the most.

Later if I want custom expensive full-chromoly shafts I can buy these.

My other issue with the Dana 44 is that the Ford seems to be an ugly swap. You have to work around the Ford leaf-spring landing:



So I think I really want to stick with the Dana 30.

(Notes:

18050.82 contains:

1. Short Tube H/D 1.25" (1) (Not Sold Separately) <== fabr
2. Long Tube H/D 1.25" (1) (Not Sold Separately) <== fabr

3. 18040.50 - Damper Bracket (1)
4. 18043.26 - Tie Rod End H/D 7/8" RH Thread (2)
5. 18043.10 - Tie Rod End H/D 7/8" LH Thread (1)
6. 18043.27 - Tie Rod End, Cross Over H/D 7/8" LH Thread (1)
7. 18050.86 - Thread Clamp H/D (4)

tower $80 (assumes 2.5" tube):
https://www.ballisticfabrication.com/products/jeep-billet-upper-control-arm-tower

tower $70 (assumes 3.0" tube):
TeraFlex 3992790 - Front Passenger Side Upper FlexArm Mount

full kit:$600
TeraFlex 3991100 - Axle Bracket Kits

Artec coil brackets TJ3015 (assumes 2.5" tube)

chromoly Ballistic Joint ball-joint

Trail Geer "Creeper Joints"

)
 
#18 ·
Where do I get a ZJ passenger side Upper Control Arm tower?
Either reinforce the original one (plate & gusset it), or cut it off, get .188" or .250" wall square tube (ie. 1.5" x 2") and high quality flex joint that come with a weld-on bushing sleeve.
You can go with a johnny joint, ballistic fab. joint, or Duroflex joint; Duroflex being my favorite of those three.

If I were you and sticking with a D30, get a HP D30 from an XJ, truss it, regear it, lock it, wheel it. R&P is gonna be the weak point in a D30 be it LP or HP version.
On a V8 ZJ with a feather-light foot on your skinny pedal you may just make it on 35s, but even on 33s or smaller it's easy enough to keep breaking R&P sets. I6 makes things survive a little better, but carnage is still possible.

You can get your ring and pinion gears cryogenically treated to make them almost as strong as a Dana 44.
You can also dance around a bonfire with a tin foil hat on your head and pretend it's gonna make a D30 bulletproof :D However, it's not gonna happen. A turdy is a turdy, and even with cryo- treated R&P set it's not really gonna be almost as strong as a HP D44 R&P is in real-world situations.

All that remains is making longer inner shafts for the CV. This I can do on my lathe. I don't have the tools to do the splines. The splines will probably be $200 at a machine shop at the most.
Eeh.. no. You can't make your own axle shaft on a lathe, not even if you had a machine shop cut or roll the splines for you. You really need to do some research on how automotive axle shafts are manufactured, especially the ones that are better than the Chinese- built shafts that are about as strong as wooden tootpicks.

Later if I want custom expensive full-chromoly shafts I can buy these.
Unless you want RCV shafts (which can be ordered as custom- length if you want), like I wrote before there is a vast amount of different length U-joint style inner cromo- shafts available for D44s. You can use the XJ/TJ/ZJ stub (outer) shaft, and use whatever length inner shafts that meet your needs.
Heck, if one was crazy and stupid enough, one could even build a custom- width 30-spline D30 axle using D44 inners of the length you need and running the XJ/TJ/ZJ stubs.

The thing is, why exactly are you looking for custom width? It's always a good idea to use shafts that are commonly found, because they are easy and cheap to replace if needed.

My other issue with the Dana 44 is that the Ford seems to be an ugly swap. You have to work around the Ford leaf-spring landing:



So I think I really want to stick with the Dana 30.
It's about the same price to build a HPD30 to be as strong as possible, as it is to build a HP D44 - the difference being that apart from the u-joints (they are the same on a D30 and D44), the HP D44 is always going to be stronger.

Like kg6mov mentioned, when using the correct version of a Ford HP D44, you're not gonna have that cast leaf spring pad on the housing.
 
#17 ·
What are you planning to do that you need cryo'd gears and c gussets? I wasn't under the impression that you wheeled much.

If you get the right ford d44 you don't have that leaf-spring perch to deal with. Mine doesn't have it.

With an hp30 you'll have better driveshaft angles and stronger gears without having to get them cryo'd or other nonsense like that.

Ballistic fab has good brackets, obviously these will work fine for a ZJ as well: https://www.ballisticfabrication.co...products/xj-tj-jeep-combo-bracket-upgrade-kit
 
#20 ·
No, a real d44 has very different inner C's. Much bigger.

The rubicon d44's use the d30 outers, but they're the only axle with that strength compromise.
 
#21 ·
Dynatrac and Currie both make heavy duty d44 inner-C's that accepts JK knuckles that are significantly stronger than OEM stuff. Dynatrac also makes TJ- style heavy-duty inner-C's that are the same strength. All of those are for 3" OD tube diameter.

Traditional D44 fronts use a very different inner C and also very different knuckles. There are flat-top knuckles available for both traditional d44s, and at least Reid racing makes a few different HD knuckle versions for JK axles.


Just keep in mind that it will probably be cheaper for you to source a matching set of JK Rubicon d44s and do custom ZJ brackets on them than it is to start building a front d44 + ford 8.8 (or 9") from scratch.


It's also worth noting that JK Rubicon front D44s have a few nice upgrades over the traditional d44s:
* Stronger R&P set, using a lot stronger pinion and pinion bearings (pretty much the same as on our d44a axles)
* They use axle shaft u-joints that are 1350- sized, where the traditional d44 and d30 use the much smaller 5-760x which is about the same as a 1310- sized u-joint.

Downside on the JK Rubi d44 axles are weak axle tubes.
 
#23 ·
No, the HP housings are a very different casting to keep the pinion lubed.
 
#24 ·
huh?

the pinion is on the passengers side of the ring-gear for the rear-axle, but on the drivers side of the ring-gear (edit: was pinion) in the front-axle

this tells me the axle bellhousings for the front and rear are the identical (LP)

the only difference is the tooth cut -- due to not wanting to thrust on the convex (coast) side of the ring-gear tooth

am i visualizing this wrong?
 
#25 ·
The gears are identical for a low pinion front or rear axle, and the housing is cast the same.

Because that means that fronts are driving on the coast side dana/ford developed the high pinion or reverse cut gear sets and a high pinion housing. It's not just a flipped lp casting because the higher pinion needs special attention to stay lubricated.

LP vs HP


Low pinion front d44:


High pinion front d44 (custom width build):


Same thing with d30's:
 
#27 ·
Who the **** is bill?

Read my response again.

The gears are identical for a low pinion front or rear axle, and the housing is cast the same.
You can't use a LP housing with reverse cut (high pinion) gears.

A rear housing can be retubed to be used in the front, but you would run the standard cut gears.
 
#29 ·
Yes.

That's the whole ****ing point of the hp30 swap. Huge increase in strength because you're driving on the drive side.
 
#31 ·
Yeah, axle and gear design is confusing, and the industry doesn't exactly make it easy to follow what's going on.
 
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