2nd Gen Non-Engine/Transmission Dually Tires

[99CumminsBoy]

Has anyone ever ran 285/75/16 tires on a dually? if so how big of a spacer will you need between the duals?

 

[terrywerm]

Have not done it in the past when I had a dually, but I am a bit curious as to why you would want to run tires that wide as duals. The spacer between the wheels would effectively move the wheel load off of the inner wheel bearing and onto the outer bearing. The way most axles are designed, the inner bearing carries the majority of the load, and the outer bearing (which is smaller) has the primary function of keeping the wheel straight on the spindle, while carrying only a small portion of the load. Moving the weight out to the small bearing will shorten its life in addition to running the risk of breaking an axle shaft, or in extreme cases damaging the axle tube.



As far as the spacer thickness is concerned, it would need to push the outboard tire far enough out that the bulges in the sidewalls of the two tires do not touch each other when the truck is loaded.



The tire size that you mention is 11" wide if I remember correctly, so you'd have to get the outer tire pushed out quite a ways from the inner one. Your outboard tire would then be out past the fender wells, too. Could get you a ticket in most places unless you add appropriate fender extensions.



Just some food for thought.

 

[sam616g]

I've seen it done on a 99 dually on stock rims. I don't know what size spacers he used but the stock rim size is a bit narrow for a tire that wide. His set up looked pretty scary. You could probably go with 255/85/16 on your stock wheels and get the same hight with out as much offset.

 

[Pmaloney]

I am running the 285's on mine and if I remember correctly I went with either a 1 3/4 or 1 1/2" spacer. I'll have to measure. Have had them on for 15,000 miles and have towed my 5th wheel quite a bit and have never had an issue.