I going to lift the truck with a 4" lift suspenion lift rough country. I was looking at dually kits then I thought about doing it to my 89 f250hd ext cad 4x4. I have already bought warn fender flares and I'm going to mod. the rear flares for a DRW setup. I've still got to get dually rims and the front adapters but what is the reason for the rear wheel spacers? I have a 97 dually it doesn't have any but it does have larger drums. Anyone know why I would need the spacers?

 

If I'm not mistaken, the axles, while both Sterling 10.25, are different widths. I think the reason for the adapters is space the wheels out far enough so that the inner tire doesn't hit the leaf springs (when using a SRW 10.25). I'm sure a search here can find the information you're looking for since I know others have looked for the same answer.

 

Thanks I'll look into that some more or go mesure my dually and the SRW just to see what the difference is.

 

Best I remember it's 4 inches longer on the dually...

 

Yup, the pickup-bed dually axle tubes (and therefore shafts) are 2" longer per side than the respective single-wheel axle, thus making the DRW axle 4" wider overall. Spares will go between the hub flange and the inner wheels, to make up for these 2" that you need for your inners to clear the springs.