TorchMadness
Registered User
I am trying to figure out what it would take to convert my 1989 F250 7.3L to a dually. Someone mentioned all I would need is the rims and tires because my rear axles already has the extra space. Any suggestions?
Make my 89 F250 a dual wheel?
- Thread starter TorchMadness
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crash-harris
Breaker! Breaker!
Also the 2-piece lug nuts for dually wheels. You can't use conical lug nuts. If you think you have the space, you'll have to mock them up and make sure the inside wheel/tire doesn't contact the spring or the bed. You'll want to cut the wheel well opening out to fit. There are lots of dually fenders being produced to convert a SRW bed to a DRW, or get a dually bed. Or just go with a flatbed. You'll also need to be sure that you have enough lug to fit and tighten both wheels.
TorchMadness
Registered User
Here are a few pictures maybe this will help see what i need.
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crash-harris
Breaker! Breaker!
Pics didn't work. Check the article on how to successfully post pics, or upload to a FSM or photbucket account and link an IMG file.
And what laser said. Those will help particularly for the front.
And what laser said. Those will help particularly for the front.
TorchMadness
Registered User
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Also, the dually rear axle is wider than a SWR axle, so if you just put dually rims on a SWR truck, they may hit the springs. Which is why you need the adapters or an actual dually axle.
icanfixall
Official GMM hand model
Welcome to the forum.
From the pics you posted about your rig going from single to dually. Your axle is not the dually axle. Sorry but someone told you wrong about yours being wide enough for a dually setup. Remember if you do not change the front wheels to the dually style you will need 2 different spare wheels and tires.
From the pics you posted about your rig going from single to dually. Your axle is not the dually axle. Sorry but someone told you wrong about yours being wide enough for a dually setup. Remember if you do not change the front wheels to the dually style you will need 2 different spare wheels and tires.
Welcome aboard 
As Gary said, you have an SRW axle...if you try to put DRW rims in the back, the inner dual will make contact with the spring.
You really want to find a DRW rear axle. Adapters will work just fine for the front axle (the OEM DRW front hub is essentially the same design), but for the rear axle, a factory DRW axle is physically wider and has wider brake shoes; 3 1/2" instead of 3" on the SRW axle. Also, the wheel bearings on a SRW axle are not in the right space for DRW rims...even with an aftermarket adapter, the center of the load with DRW rims will be offset compared to the center of the load the wheel bearings are designed for. That'll put sideways pressure on the wheel bearings, which can lead to trouble down the road.
Since you're running a flat bed, you might be able to get away with a chassis-cab axle, but I'm not 100% sure...either way, make sure you get an axle out of an F-350 (8 lug), not an F-450 (10 lug).
Hope this helps some
As Gary said, you have an SRW axle...if you try to put DRW rims in the back, the inner dual will make contact with the spring.
You really want to find a DRW rear axle. Adapters will work just fine for the front axle (the OEM DRW front hub is essentially the same design), but for the rear axle, a factory DRW axle is physically wider and has wider brake shoes; 3 1/2" instead of 3" on the SRW axle. Also, the wheel bearings on a SRW axle are not in the right space for DRW rims...even with an aftermarket adapter, the center of the load with DRW rims will be offset compared to the center of the load the wheel bearings are designed for. That'll put sideways pressure on the wheel bearings, which can lead to trouble down the road.
Since you're running a flat bed, you might be able to get away with a chassis-cab axle, but I'm not 100% sure...either way, make sure you get an axle out of an F-350 (8 lug), not an F-450 (10 lug).
Hope this helps some
duallies are a love/hate relationship
nope.though they may be slightly wider than a srw pickup axle,the primary difference in the f350 cab n chassis axle is simply the spring mount locations.if you cut and re-weld them to the proper pickup locations,your right back where you started without enough width to run duals.
there are only two ways to run duals on a srw f350 or f250.adapters or a drw f350 pickup axle.
TorchMadness, unless you run out of tire rating for your payload just run 'er srw.
the duallies really firm up the ride and kill your traction.they're not anything you want just for looks imo.for towing they really cut down on the sway and make it a dream to tow compared to srw.they're basically just a necessary evil if you haul or tow heavy is all.
i have two duallies and believe me,they're a constant love/hate relationship.
it would be killer if the outside wheels could be lifted/lowered via hydraulics or something.of course stupid expensive even if designed correctly.
nope.though they may be slightly wider than a srw pickup axle,the primary difference in the f350 cab n chassis axle is simply the spring mount locations.if you cut and re-weld them to the proper pickup locations,your right back where you started without enough width to run duals.
there are only two ways to run duals on a srw f350 or f250.adapters or a drw f350 pickup axle.
TorchMadness, unless you run out of tire rating for your payload just run 'er srw.
the duallies really firm up the ride and kill your traction.they're not anything you want just for looks imo.for towing they really cut down on the sway and make it a dream to tow compared to srw.they're basically just a necessary evil if you haul or tow heavy is all.
i have two duallies and believe me,they're a constant love/hate relationship.
it would be killer if the outside wheels could be lifted/lowered via hydraulics or something.of course stupid expensive even if designed correctly.
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crash-harris
Breaker! Breaker!
I can vouch for this. I put a C&C 10.25" under the rear of Bruiser and dually wheels hit the leaf springs before the wheel mounting surface. Currently running 37 SRW's with 3.5" spacers on that truck.
Glad someone brought this up. So to make sure I'm understanding this correctly. If I want to turn my truck into a DRW I should pick up a rear DRW axle and not use a conversion kit. But on the front it would be ok to use the adapter kit? Does the adapter kit fit over front lock out hubs?
Correct
Look at @laserjock 's picture to see what an aftermarket adapter looks like, and here's what a factory DRW hub looks like:
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Other than the adapter that's bolted on, it's identical to an SRW hub.
And, for the record, here's a shot of a DRW brake drum compared to an SRW brake drum:
DRW:
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SRW:
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I was mostly taking the picture to show the difference in brake drum width, but you can also get an idea of the difference in distance between the backing plate and the spring perch. Both of these axles are pickup axles.
Just to complete the story, here is what the rear adapter looks like installed.
It makes up the space difference and also gives the bigger lugs with flat face lug nuts you need for the dually rims.
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It makes up the space difference and also gives the bigger lugs with flat face lug nuts you need for the dually rims.
