2015 3500 SRW swap to DRW.

[TMassey]

Good evening, 

 I’m beginning a project to fab a service bed for my 2015 GMC Sierra 3500 SRW. I’ve been considering swapping the single to dual and wanted to see what issues may arise legally and physically with the project. I want to see if the rear end is in fact the same on the single verses the dual. I’m not towing heavy loads that would be outside of what my single rear wheel calls for. I just think with the added weight of the service bed, duals would handle better. I’ve seen on the forum a gentleman trying to do it on a 2500 HD and I agree that could arise legal issues. But if in fact the truck is already a 3500 I think mechanically is doable. Thanks for anyone’s time in this matter and be honest but open minded please. 

[davester]

DRW Rear diff is wider than the SRW version, and bolt-on adapters are needed to enable the same rims to be used front &back.  Don't know if you need different shock/spring mounts or other differences, such as brakes.  Then there is the hips on the bed, earlier trucks had them as separate, replaceable pieces, haven't looked at new ones (some are smooth over the whole side of the bed, so I guess it may just cover the whole side, making it that much more expensive to fix/replace when something tags it).

 

As for legal issues, if you are at all concerned about them, you need to spend some money and talk to a lawyer or someone else versed in that kind of thing, for where you are and where you plan to drive.  Anything you get on a forum like this is as valuable as what you paid for it...

[TMassey]

Good morning Davester,

 Understood. There is a company that makes a nice set of steel adapters for the front and rear as that would get me the clearence needed with the leaf springs. I can check with a friend as to the leaf spring differences from a single to dual and do that swap as well if needed. The bed wont be an issue as ill be pulling it and fabricating a bed from scratch around the duals. Ive also been contenplating airbags as well for added cusion for any application needed. As far as the breaks go, i think they are the same just on a different style hub. 

 With the legal side of things, all the trailers i have are well in speck with what i already have my truck rated for. When i build the service bed ill be using minimal material to keep weight low with proper gusseting and heavy material where needed around the goose attachment. If i were to get pulled and the trailer tounge weight is within the spec on the door for the SRW then i think i should be fine. Thanks for the info sir. 

[davester]

You want to use spacers on a SRW axle so you can put DRW's on it?  That I would not recommend...

[TMassey]

They would be steel adapters for the swap. Not cheep ones either. Looking at the parts for the front hubs is my main concern with that spacer but looking at. Dually set up hubs are theoretically the same as the adapter, just a two piece. I’ve read the horror story’s about the aluminum spacers. Not interested in that! 

[davester]

The front spacers (don't know why you wouldn't use oem takeoffs for them), keep the wheel properly centered over the hub, with dually rims.

 

Using spacers on the rears doesn't do that, which is why GM puts in a wider axle, so the center of the wheels are centered over the hub.  Putting roughly double the mass way offset of the hub isn't a great idea.