Axle width between full and bronco width?

[brewchief]

I'm planning on build a hi pinion d44 for my 74, I have a 78 f250 housing.
I was originally planning on building it early bronco width but have some concerns that it might have oil pan clearance issues at full compression, I don't really want to go full width but was thinking of something in between. IIRC an early bronco axle is 7" narrower then a full width, instead of narrowing it the full 7" maybe building it 3 or 4 inches narrower would work, that should give a bit more oil pan clearance and I could probably get away with not building a wider rear axle right now as well.

Suspension is probably going to end up 3 link with coilovers(and hopefully a spot for future bypasses) although I haven't ruled out radius arms completely yet.

Anybody done this? Bronco sees a very small amount of street driving, mostly just sand dunes.

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[garberz]

I would double check on the pan interference. I run a EB width HP44 from a 79’ F-150 and an Explorer oil pan, less than 3” of front suspension lift. No clearance issues with the pan. You can make it any width by having the axles cut and resplined. But you should have a back up set made as well.

Mark

 

[Seventee]

EB width is 6" narrower. Keep in mind that if you were to only narrow 3-4" you would also need to do a custom housing/shafts for the rear because it will be a non-standard width.

The general consensus is 3"+ lift and stock oil pan, you won't have clearance issues.

 

[nvrstuk]

Don't be afraid to do it right! You might want to take some accurate measurements from pinion centerline on BOTH axles. Then figure out how far you need to (and you will unless you go 5" suspension lift or better) to move the pinion towards the DS. IF this rig sees the sand dunes all the time then you don't want what most guys do and have the pumpkin clearance the oil pan for street driving.

I'm guessing cutting 2 1/2"- 3 1/2" off the DS axle tube for max travel. Really depends how much up travel you want really- with GOOD bump stops (air bumps).

I narrowed my '78 D60 from an F250 2 3/4" on the DS to move the pumpkin over for 6" uptravel while only running 2 1/2" suspension to clear my 40"s and to clear the driveline/trans clearance also. I am at 65.5" WMS. Like you I did not want FW for several reasons.

Then narrow the PS to match the distance from frame to WMS on the DS and you are good. Get some RCV axles and cut your wheel hop in the sand dunes by 75% or more. REALLY worth it when doing high speed constant wheel spin wheeling especially when turning slightly.

Do what YOU need to do to make it work for your wheeling. Probably need to truss that D44 to keep it from grenading when catching a little air. Why not go HP D60 and never worry??

 

[Broncobowsher]

It isn't a matter of how much lift you have. It is a matter of where you have the bump stops set at. Which is also a factor in how much up travel you have.

Another common snag is exhaust clearance.

If you already have the parts and have some time, just mock the axle into the Bronco. Try it at different offsets. Don't worry about the passenger side sticking out, that is what narrowing the axle will fix. Look at where the pumpkin lands during the stroke. Look at what shifting it around will do. Not a full install, Ratchet strap the axle to the radius arms. Or make new arms out of whatever you have handy. Only needs to be strong enough to cycle the axle. Old fence post, 2x4s, whatever is handy.

Depending on how much tire you plan on running you may end up moving the bump stops down enough that diff clearance isn't an issue. Or you want a ton of stuff potential with small tires, which case you are pretty much hosed no matter what.

But mock up will give you the answers you are looking for.

 

[brewchief]

Right now I run 35s with 3.5" deaver coils, front factory bumpstops replaced with a similar height poly bump and the frame looks like chrome from them hitting so much, I absolutely don't want to rely on lift to keep the oil pan from being clearanced.

I plan on chromo axles so width shouldn't be a big deal although I will look for a factory length if possible to make it easier for future replacement.

Don't really want or need the extra weight of a 60 up front and don't want to go to 8 lug and don't want the cost of getting a 60 to a 5 lug that will clear a 15 wheel.

Exhaust clearance is a problem now, my headers hit everything, I will be going to a set of maddog fenderwell headers.

I know I have to mock it up, I was just trying to see if going in between made any sense.

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[nvrstuk]

My comment about 5" susp lift was/is how most get a hi pinion to fit. They put in taller bumps and have clearance with either less suspension movement up front or close to the same.

D60's typically weigh 65# more than a D44. I have all the weights documented on the same scales. Swapping wheels, yes - big expensive hassle.

Shorty's will fit even if you need to cut the DS flange off. MadDogs aren't coated and they aren't SS. I'm assuming by sand dunes you mean by the ocean so coating them wod be important.

You need good air bumps for real dune running. Saves your teeth from chipping.

 

[brewchief]

I'm in Michigan so sand dunes are thankfully salt free, unfortunately they are nowhere the size of some other dune areas.

I'm running a C6/205 so room for exhaust is a bit lacking.

65# wouldn't be terrible but then you either need to switch it to 5 lug or move everything to 8 lug, unless you build a custom floater 9 inch that means a heavier rear as well. I've yet to hurt anything in the stock axle including the stock small u joint shafts.

I know what your saying with the air bumps for dune running, I plan on coilovers and air bumps to start with room to add a bypass in the future. Rear will end up 3 or linked with coilovers and bumps as well.

Right now I'm using all the driveshaft angle I have at full droop, going to a high pinion should allow for another 4 inches or so I hope, I built the C6 with the short output so only have room for a 1310cv and even that is tight( like grind the corner of the trans pan off tight).

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[68ford]

https://www.instagram.com/p/Bwk7t2WAoYV/?igshid=k9oxpsudpmkd

Just go full width. You'll need the room to clear fenderwells headers, coilover and bypass . I know because I have just that. Also with added speed potential of properly tuned coilover/bypass, you really should have full width for stability and keep it as low as possible. Keeping it full width let's the diff not be anywhere near the pan and the axle can compress beyond stock bumpstops. top of diff contacts the engine mount tower while everything else has around 2in clearance if I remember correctly. You can end up with a low ride height and good up travel from ride height. Mine is roughly 2in lift and I have around 7in up travel from ride height, axle compression would allow more compression travel, but shocks end up through the hood. Additional distance between the drive side frame and tire also allows for a much longer panhard bar. That is also a must for going fast. Stock left panhard bar makes the axle shift around 3 inches over 14in travel. Definitely not good going fast.

 

[nvrstuk]

If our Early Brncos were on a pickup frame we wouldnt be having this conversation!! LOL

However, FW where I live in the PNW and you cantget thru the "good" trails because you are too wide and cant turn between the trees... and no room for multipoint turns either- tight!

So weigh your pro's and con's and do what ya gotta do.

Bigger isnt necessarily better. Unless its HP.

 

[68ford]

If our Early Brncos were on a pickup frame we wouldnt be having this conversation!! LOL

However, FW where I live in the PNW and you cantget thru the "good" trails because you are too wide and cant turn between the trees... and no room for multipoint turns either- tight!

So weigh your pro's and con's and do what ya gotta do.

Bigger isnt necessarily better. Unless its HP.

What width wheels are you running brian? At least 9s I guessing? I'm assuming your narrowed housing but with considerably bigger tires is likely as wide has my d44 with 8in wide wheels and 35s.
And you're right, anyone building a highly modified EB starting with small axles, brakes and worn out drivetrain would be worth looking into a 4x4 f100 shortened chassis swap. Especially if doing a rear 4 link. Narrow frame makes for weak upper link spread.

 

[nvrstuk]

Raceline Monsters. I believe at 9", custom 4 1/4" BS.

65.5" / 65 wms

Outside of 40" MTR's is 80.5". Built to squeeze onto btw my trlr fenders and a few trees on our favorite trails

 

[brewchief]

https://www.instagram.com/p/Bwk7t2WAoYV/?igshid=k9oxpsudpmkd



Just go full width. You'll need the room to clear fenderwells headers, coilover and bypass . I know because I have just that. Also with added speed potential of properly tuned coilover/bypass, you really should have full width for stability and keep it as low as possible. Keeping it full width let's the diff not be anywhere near the pan and the axle can compress beyond stock bumpstops. top of diff contacts the engine mount tower while everything else has around 2in clearance if I remember correctly. You can end up with a low ride height and good up travel from ride height. Mine is roughly 2in lift and I have around 7in up travel from ride height, axle compression would allow more compression travel, but shocks end up through the hood. Additional distance between the drive side frame and tire also allows for a much longer panhard bar. That is also a must for going fast. Stock left panhard bar makes the axle shift around 3 inches over 14in travel. Definitely not good going fast.

I was hoping to avoid going all the way to full width but still reap some of the benefits, lol.

Keeping it in between I think I could avoid building a new rear at this time as it wouldn't be noticeable, of course at the dunes it wouldn't matter as most wouldn't notice the difference with paddle tires on 15x14 wheels on the back.

The longer panard makes sense.

Right now I have 3.5" lift springs and a 2" body lift, I'd be ok with keeping the same ride height or maybe slightly lower, getting rid of 1" of the body lift wouldn't bother me a bit.

Are you linked or radius arms in the front?

I was thinking 3 link in the rear with a wishbone style upper, there are a few early broncos running around here with 4 links but it's probably not ideal.

Remember speed is relative, we have a pretty small dune area so there is only so much opportunity to run fast.

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[68ford]

One thing to consider is the height of a 3 link on top of the diff. You really need to design it so the bolt going through the heim is vertical. Otherwise you side load the being and they are not meant for that type of load especially to that extent. You will need a elevated area of the floor so the upper wishbone can come through the floor. Unless you limit up travel, but what's the point of decent suspension only to limit it. It will only droop so far with stock wheelbase driveline lengths. So taking advantage of up travel is you only option. I personally like 4 links. Easier to deal with 2 straight links than a wish one plus it is much much easier to adjust your thrust angle.
https://www.instagram.com/p/BWjIEujlIfe/?igshid=1j7wqsy5zcou2

Use radius arms on the front and take advantage of that making your front axle a sway bar. Otherwise you be also needing room for a long travel sway bar at addition expense.

 

[LSharpNM]

https://www.instagram.com/p/Bwk7t2WAoYV/?igshid=k9oxpsudpmkd

Just go full width. You'll need the room to clear fenderwells headers, coilover and bypass . I know because I have just that. Also with added speed potential of properly tuned coilover/bypass, you really should have full width for stability and keep it as low as possible. Keeping it full width let's the diff not be anywhere near the pan and the axle can compress beyond stock bumpstops. top of diff contacts the engine mount tower while everything else has around 2in clearance if I remember correctly. You can end up with a low ride height and good up travel from ride height. Mine is roughly 2in lift and I have around 7in up travel from ride height, axle compression would allow more compression travel, but shocks end up through the hood. Additional distance between the drive side frame and tire also allows for a much longer panhard bar. That is also a must for going fast. Stock left panhard bar makes the axle shift around 3 inches over 14in travel. Definitely not good going fast.

This is my take. Go full width and don't look back. The stability and packaging benefits cannot be overstated in my opinion.

Raceline Monsters. I believe at 9", custom 4 1/4" BS.

65.5" / 65 wms

Outside of 40" MTR's is 80.5". Built to squeeze onto btw my trlr fenders and a few trees on our favorite trails

For what it is worth, one of my rigs is running 38"x13" tires on an unmodified '78-'79 F250 Dana 44 (not sure on the wheel specs) and it is almost the same width as your rig since it just fits between the fenders on my car hauler which are 81.25" apart. Wheels make a huge difference in actual overall width, and can go a looong way towards compensating for a non-narrowed full width axle.

For a few more data points, my 2007 Superduty axle is 72" WMS, but with the factory wheels (17"x7.5" ~5.75" backspacing) and 285 (11.25" wide) tires, it is only 78" to the outside of the tires. Another one of my rigs has a 59.5" WMS axle with 37"x12.50" tires mounted on 15"x8" wheels with 3.75" backspacing and is 73.5" to the outside of the tires. Only a 4.5" difference in overall width despite a 12.5" difference in WMS width (although ~1.25" is due to the difference in tires).

 

[Madgyver]

This is my take. Go full width and don't look back. The stability and packaging benefits cannot be overstated in my opinion.

For what it is worth, one of my rigs is running 38"x13" tires on an unmodified '78-'79 F250 Dana 44 (not sure on the wheel specs) and it is almost the same width as your rig since it just fits between the fenders on my car hauler which are 81.25" apart. Wheels make a huge difference in actual overall width, and can go a looong way towards compensating for a non-narrowed full width axle.

For a few more data points, my 2007 Superduty axle is 72" WMS, but with the factory wheels (17"x7.5" ~5.75" backspacing) and 285 (11.25" wide) tires, it is only 78" to the outside of the tires. Another one of my rigs has a 59.5" WMS axle with 37"x12.50" tires mounted on 15"x8" wheels with 3.75" backspacing and is 73.5" to the outside of the tires. Only a 4.5" difference in overall width despite a 12.5" difference in WMS width (although ~1.25" is due to the difference in tires).

Thanks for this info.
I've been researching wheel offsets and backspacing to match the 92 F350 D60 that I got.
Your numbers paints a clearer picture of my options. Looking at Raceline Avengers 17"x9" 5.8" backspacing or +20mm offset

 

[Yeller]

There’s a lot of experience responding to this thread all of which own some exceptional performing equipment.

I’ll chime in about wheel width. My axle is 69” run an 8” wheel with 4” of back spacing with 37x12.50 tire and and 81” wide to the outside of the tire. Just keep in mind that it can go too far you don’t want your hub ends being the wide point unless they are really robust mine are just beyond flush with the wheel and have been rubbed on enough all the markings are worn off.

68ford is correct to get all of that on there you will need every bit of room you can muster packaging is a PITA but when done right worth every bit of the time and effort. As for frame width bronco frames are in the way all the time unless you don’t start with one at all

 

[nvrstuk]

I typed b4 reading Steve's post...should have read it because I erased my concern which was exactly the same...hub protrusion....

Remember thise little tiny screws that hold the hub on won't take much of a whack!

Thatsthe reason I went to another weeks worth of work on mine... take it off the axles i stead of trying to do it all with wheel offset. That and scrub radius comes into play when playing with huge backspacing numbers

 

[Madgyver]

leaning on not cutting axles since i'll need new wheels anyway.
and i thought my bronco was done...

 

[nvrstuk]

You'll be good.

Your Bronco is way cool the way it sits!

2 things:

1- our Broncos are never done!! lol

2- the trails in your forests arent the same as the trails in our PNW forests.

No options here. 84" wide? You're taking the wheels off to get btw the 2' dia trees...