Allright i know this is the probably the wrong place to post this but over in the second gen forums no one replied over her, i get responses another thing is that i figured it would be similar to a 3rd gen so here goes...
I have a 96 dodge 3500 that i would like to put a set of 315s on. That is almost 12.5 inches wide. My question is what size spacer will i need to fit them on factory wheel. I know the factory wheels arnt quite wide enough, but the tires are just layin aroud goin to waste anyways. Also, the truck usually has a pretty good load on it.

Thanks

 

I've never used spacers on dually wheels.
From posts that I've read on this and other forums over the years, most folks use them to run large tires for the McDonald's factor.
Also most agreed that the use of spacers would reduce your load carrying ability due to the increased stress on the axles because of the off-center loading of the wheel/axle bearings.