I have been contemplating this and here are the measurements and decisively what you need to do:

If you have the stock Dana 70 SRW model it is exactly 2 inches narrower than the cab and chassis model 70.

That said, you will need to add a 1" spacer against the brake drum and then install your dually rims (stock).

If you don't add the 1" spacer, for instance, 7.50- 16 tires will rub the u-bolts. It is exactly 1" between the u-bolts and the tires. 235 85 16 tires would have a very similar effect. Any tire that is wider will rub regardless of the 1" spacer. At that point a thicker spacer will be necessary.

Adding the 1" spacer will require longer studs than the stock dually legnth. the studs for a dually are _____" dia? , and the studs on a SRW model are 1/2". Doing this conversion will require the use of the larger studs and nuts if you are going with a stock setup as far as rims. The nuts are coined as well as are the stock Dodge rims.

I haven't gotten as far as to start the transformation, so I ask all of you "will the larger dually studs press in to a stock SRW drum?" If not the drums need to be converted.

This is the rear setup, the front will require you to aquire a set of hub adapters to provide the offset for duals. Will the front hubs bolt on to a SRW front axle?

This information applies to converting a SRW to cab and chassis style rear dual axle. The rear dual for pickup box applications is 5" wider than the c/c Dana 70 dual rear. I suppose this wider axle was to provide wide support for a slide in camper application?

If you intend on converting and adding the stock dually bed, the rear axle(tires) will sit well inside the fenderettes and it kinda looks silly. To do a pickup box conversion you really need to source a pickup style DRW axle.If you are going the flatbed/ dump route, it is a pretty easy conversion with what you have.

I realize I may seem to be reinventing the wheel here, but there was no definitive post , just some trial and error stories and a lot of wondering. Measurements were taken from 92 SRW from factory truck and a factory built c/c model with duals.

 

You need to re-think your idea of how the spacer is mounted.

On all of the bullet-proof SRW to DRW spacers, they have SIXTEEN holes; eight of these holes have deep conical-nut pockets, such that the original stock lug-nuts fasten the spacer to the hub; the other eight holes are fitted with standard DRW studs which the wheels get bolted to in the normal fashion.

If the wheels are also hub-centric, a shoulder is provided for this, IF THE PROTUDING PORTION OF THE AXLE ALLOWS; on most floating-axle rears, the hub interferes with being able to include the hub-centric locating shoulder on the spacer.

I see these types of SRW-to-DRW spacers often at swap-meets and the like and they usually trade for around a hundred-bucks/pair.

Most are about three-inches thick.


A thick spacer that depends on longer studs is just an accident waiting to happen.