1985 f250 4x4 6.9 idi Dually conversation

[Austin fretwell]

I have a 1985 f250 srw I am doing a Dually conversion on and I am wanting some advice. Do I just add adapters in the rear or just go with a drw rear end and does anybody on here have a set of adapters for the front stock preferred

 

[79jasper]

If you are actually towing often or heavy, get a drw axle.

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[chillman88]

You can do either for the rear but as Jasper said, a whole rear end is the RIGHT way to go. Just make sure you get the correct dually rear, cab & chassis trucks have a narrower frame and won't work. You need a dually rear from a truck that originally had a pickup bed on it. Measure your spring pad mounting width and you'll be ok. The correct axle will drop right in and bolt up fine.

 

[Austin fretwell]

Okay guys thanks another thing I know the frame is narrower I think it’s a National standard for all cab-chassis trucks ford doge etc. is the actual rear end housing narrower and if so how much I don’t mind welding on new spring pertches

 

[chillman88]

Okay guys thanks another thing I know the frame is narrower I think it’s a National standard for all cab-chassis trucks ford doge etc. is the actual rear end housing narrower and if so how much I don’t mind welding on new spring pertches

I can confirm this later if nobody else does but I'm pretty sure I heard the actual housing IS narrower. As in there's not enough room to actually move the perches. I'm hoping someone else can confirm so I don't have to crawl under my parts truck in the snow lol!

 

[Austin fretwell]

Okay man well thank you if nobody gives me a answer I would greatly appreciate it

 

[snicklas]

I can confirm this later if nobody else does but I'm pretty sure I heard the actual housing IS narrower. As in there's not enough room to actually move the perches. I'm hoping someone else can confirm so I don't have to crawl under my parts truck in the snow lol!

I’m not 100% sure, but I think a SWR and a C&C axle are about the same width, with the spring pads in a different location. The DWR axle is much wider, something like 6+ inches wider.

A C&C has a frame width of 36 inches and is fairly straight and flat. A truck that has a pickup box is wider, and had a “hump” in the middle.

A C&C dually uses a SWR width axle also, since the frame rails are narrower, the duals will fit.

So, I believe;

SWR Pickup, and C&C SWR or Dually use a similar width axle
DWR (dually) Pickup, much wider rear axle.

A 4x4 uses the same width front axle. The difference is at the wheel, with a dually hub, or dually adapters.

 

[79jasper]

Iirc, a cc axle under a srw/drw truck, the inside dual will rub the frame.
This axle swap thing is brought up quite a bit.

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[Thewespaul]

Yep, cc drw axles are too narrow, but I have seen some guys get around that by adding spacers, but if you are going to be hauling a lot your best bet is to get a regular chassis drw axle. Not only are these axles wider, the bearings are moved out further so that they sit nearer to the centerline between the two tires. A regular srw axle with drw adapters will have a significant increase of leverage acting against the bearings since the centerline of the tires is 6” away.

 

[FarmerFrank]

Shuttle vans have a very wide frame. Can't recall what it was but I had to move the perches in.

Axel was from a 99 E-350 shuttle bus. It's a tad wider than my flat bed, but worked good.

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[Austin fretwell]

Heck ya all great info thank y’all so much I will just pick up a regular drw rear axle I have found front adapters I can buy for 300 or so built just like stock

 

[BR3]

Snicklas was pretty much right, though there is a very small difference in srw and drw chassis.

For point of reference, wheel mounting surface distances per oe setup

Chassis cab-69"
Pickup single wheel- 70"
Pickup drw-72"

Three inches is a lot of difference when talking wheel/tire/load spacing and where things land