I think I’m going to step away from the cab for a minute and let a plan for what I want to do develop/marinate, and/or see if something presents itself. Before I rolled it out so I could start frame stuff I decided to test fit the tires. These are 315/75/16 tires. The minimum recommended rim width for them is 8”. These dually wheels have a rim width of 6”. I’ve read of numerous people running this exact combo and being fine, even towing….and since everything on the internet is true, I should be fine, but…..
I’m just not sure what I want to do though. I have been working on a plan to widen my wheels that I know will work, but it will be a lot of work to do that. And if I widen them, which direction should I go? Or should I go both ways? There are advantages to all options. Regardless of which option I choose I will need spacers in between the rear wheels, but the actual thickness of it will depend on what I do with the wheels.
With the way this is mocked up, if I stay with 6” rims, I will need about a .5” spacer behind the inner dual since it’s solidly on the spring right now (this is a cab and chassis axle so it’s narrower) and this represents a 2.75” spacer in between using the 2x4s to space for mockup. I could probably get away with 2.5” since there’s 1.5” between the tires right now due to my 2x4 mockup spacers.
I can make a dually wheel with a 7.5” wide rim with just one seam using a combo of single and dual wheels, which I think is close enough to the 8” to be ok. If I add that to the convex side, that should get me far enough away from the spring that I then won’t need an inner spacer (I’m figuring the sidewall will move half of the additional rim width, so .75”), but then I’m going to need 4” of spacer in between the wheels (2.5 + .75 + .75).
If I add the 1.5” to the to the concave side, I’ll need probably 1.25” spacer behind the inner dual and then about 1” between the duals (2.5 - .75 - .75). I hadn’t done the math until now….those thinner spacers sound better than the 4” spacer.
Or if I make a wheel that has an 8” wide rim with 1” added to the concave side and 1” added to the convex side, I think I will need the same spacers as the 6” combo. One advantage to this combo is that my scrub radius in the front will be the same as stock.
So I have a few routes I can go. The easiest is to keep the 6” wheel width and bolt on the necessary spacers. If nothing else, I could start this way since I’ll just be using the truck for trips up and down the road to move dirt and if I find issues then I can change the wheel situation later.
I also test fit in the front just to see. Right now it hits the pitman at full lock, but in reality that won’t happen when I’m done - 1. I’m going to have crossover steering instead of the stock push-pull situation, so it won’t be in that same spot and 2. I’m going to have 8” lift springs in the front so the center of the tire will be much lower.
Does anyone have real world experience with wide tires on narrow rims to share?
