7.50-16 tires on 90's dually? Clear 2WD offset wheels?

[Detroit80]

Truck is a 1990 CCLB diesel 4x4. Started life as a SRW, previous owner swapped in a DRW front D60 with 2WD offset wheels, and I added a DRW rear Sterling, along with 4 more 2WD offset wheels..before learning that there were differences between 2WD and 4WD DRW wheels in the offset. I'm currently running SRW wheels on the back, DRW wheels up front, all with 265/75R16 tires...and am at that point that I need new tires yesterday. I want the DRW set up for additional stability while towing/hauling (my truck camper is a few thousand pounds, plus I routinely pull a 10K pound loaded trailer).

So now I find myself with 6 wheels that were meant for 215/85R16 tires. My speedo is dead on with the 265/75R16 tires, and given that 99% of my driving is freeway/interstate, I don't really want to go to the shorter tires. I'd actually rather go to a slightly taller tire, but don't want to get into spacers or stupid expensive aftermarket wheels to get there.

So I find myself looking at 7.50-16 tires...can get them relatively cheap around $120/tire, such as the Power Kings that look like vintage snow tires. On paper, it looks like the perfect solution - narrower width similar to the 215 tires, but with the 235 tire height. So I _should_ be able to fit these on the 2WD offset DRW wheels without them touching while loaded, while maintaining current performance/freeway RPMs? I realize these are bias ply tires, with the reduced ride quality, but hey..it's a loaded 1 ton truck, and I honestly have zero complaints about ride quality even in my '59 International 3 ton truck with OLD school bias plys on it.

But will they fit correctly like I'm thinking? No one local stocks these things, and I don't really want to order in $800 worth of tires only to find out they don't fit right, and I can't return tires that have been mounted.

 

[u2slow]

Most spec sheets show the 7.50 as about 1" narrower than than the 235... so at that point you're basically at the 215. I'd give it a go. If you need that extra 1/4", a pair of the 4x4 or E350 wheels are likely cheaper and less trouble than spacers.

Your tire plight is exactly what keeps me running SRW. I have two Dodge DRWs for donors... and they sit. It's much easier to just shoe up with a pair of stout tires than to mess with 4 or 6. IMHO, a big chunk of stability is a wide axle, and decent springs.

 

[Detroit80]

Most spec sheets show the 7.50 as about 1" narrower than than the 235... so at that point you're basically at the 215. I'd give it a go. If you need that extra 1/4", a pair of the 4x4 or E350 wheels are likely cheaper and less trouble than spacers.

On paper, yes. But, I also know the profile on many bias tires can differ from the profile on radials, and I'm not 100% how that will work once mounted up. Based on my observations, it seems that most bias ply tires have a considerably wider outside sidewall to outside sidewall width than tread area width, and I'm not 100% just how these tires are measured. So if the width is based on tread area, I could very well end up with miles of space between the _tread_ areas, with little space between the sidewalls, where it really matters with a dually.

I _believe_ that ALL of the earlier coined wheels were the same 5.00" offset as the newer flat faced 2WD wheels, and most (all?) of the earlier trucks came with 7.50-16 tires factory, so at least in theory...I SHOULD be OK. But also would be a whole lot more comfortable before shelling out over $700 in tires just to try this, lol.

Your tire plight is exactly what keeps me running SRW. I have two Dodge DRWs for donors... and they sit. It's much easier to just shoe up with a pair of stout tires than to mess with 4 or 6. IMHO, a big chunk of stability is a wide axle, and decent springs.

Easier for you, maybe, lol. Easier for me? Not as much when I have to carry two different spares, because I can't easily run a SRW wheel on a front DRW axle. Also can't easily rotate tires that way either.

Proper? Well, consider something like the Michelin LTX that I have on my other truck in a slightly larger 245/75R16 size. Load capacity max in a SRW configuration - 6,172lbs. Loaded up camper on the bed plus tongue weight of trailer is going to push me close to the limit, if not going over. An overloaded tire blowout on the interstate with a high COG camper on the bed isn't exactly my idea of a good time, lol.

The 7.50-16 tires I'm looking at in a DRW configuration - 9,876 pounds. Quite a bit of extra safety cushion there. I'm not sure there exists a tire that will fit a 16" light truck rim, not intended for trailer use, that is also rated for 4,900+ pounds.

The other side of this is I've looked for the higher offset wheels, with next to zero luck so far. I ended up with a single 5.35" offset wheel when I bought the other DRW wheels, without even realizing it. Wasn't until several months later when I was using a couple of these wheels as large spacers for another project that I couldn't get things to level out quite right, and realized that this wheel was just slightly wider than the others. Started running part numbers on the wheels, and learned the different offsets. I found one single of the 5.15" offset wheels in the local junkyard a few days ago, with the rest being 5.00" offset or earlier coined wheels. I have come across 1 set of 4, and 2 partial sets, of factory Alcoas in the past year (before learning of the different offsets)...all sellers wanted at least $800 for what they had. TONS of 8x170 Alcoas out there, but finding them in 8x6.5 pattern has been the proverbial needle in a haystack.

I've "found" several sets of what has been claimed to be 4WD dually wheels in various other junkyards locally using listings on car-part.com. But upon showing up to pick up the wheels, they ALL turned out to be the 5.00" offset wheels being sold by places more than happy to tell me whatever they think I want to hear...because "all dually wheels are the same anyways".

 

[u2slow]

Sorry, I missed the bias-ply bit. My 7.50R16s have been radial.

I have not had a problem finding SRW tires (pair) to cover me up to 8000# which meets/exceeds most DRW axle ratings. I've also run a pair of 19.5's to cover me to 9600#.

How about redrilling a set of the 8x170mm wheels?