converting single to dually wheels


Junior Member
New York
Hello All,

I am looking to but duals under my 91 GMC 3/4 dump body and seen a kit in jcwhitney that would do this and also have been told that all I need to do is get longer studs and then put some budd wheels underneath. What is the best way if this is to be done if possible. Thanks

For nothing heres my two cents. If I was doing that(mines already a dually) I would look into getting a complete dually rear axel. Here in Ct. we have a Bargain News Paper cost about 1.75 and its full of stuff. A complete dually rear end with tires and springs cost approx. $200-400. Theres been plenty to choose from too. I was thinking about one when I needed some springs. This set up should bolt right in to your truck, but you can't inter swap parts from one to the other. The only thing thats inter swapable is the gears if you have a 14 bolt full floater. Check this out first. Instead of doing a look a like get the real McCoy. You'll be better off.;)

karl klein

Senior Member
the problem with that is you have to get the same gears as before, the springs have to line up, the shock mounts have to line up, brake lines, and drive shaft

Chuck Smith

2000 Club Member
Do a search in this forum. 75 (Rob) has already posted the differences between dually and single rear wheel axles as far as spring mount locations, shock mounts, etc.


75 Addict
Here's a couple of discussions on the topic:

These were trucks in the 73 to 87 model range, I don't know how much things changed by 91 as far as frame widths, spring pads, shock locations etc but in general, I would say that if you're serious about "going dual" you are better off with an axle swap. IMO the kits are for "the look" but aren't a real dually, the reason for the extra two tires in the first place is payload and by putting on a kit conversion you are still using the same 3/4 ton brakes etc to stop the extra weight that extra pair of tires can carry.

Depending on which axle is in your truck now, you may have to modify (ie shorten, possibly different rear U-joint) the driveshaft. When I put duals under my 75 many years ago, the driveshaft had to be shortened by a couple inches due to the larger "pumpkin" on the dually axle.

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