jefe here. The term, 'super single' means different things to different people. They have been around a long time and have their good/bad/ugly, just like any other setup. I am the self proclaimed Sultan of Super Singles on this forum and have some observations.
A super single is essentially a wider, studier tire with an accompanying wider rim that is to take the place of two tires, with a footprint about as wide as two slimmer tires put together. Why use SS's? Michelin tested the wheels off super singles and found they saved fuel as there were only two sidewalls to flex instead of four. Also, the combined unsprung weight was higher with duals. Two wheels, two tires.
Why would I use super singles? These have a 15.5 inch wide tread on 12 inch wide wheels:
1. to have a larger footprint that could be pressured down to 'float' on sand and even snow. This does not work very well if you use any .5 wheels/tires. Why? It's a different design made for high load capacity and no lowering of the pressure. That little ridge you get with a non-.5 wheel allows the bead to stay on the rim longer at low pressure. This is why I used 375/55R16 (33x15.50R16) Mickey Thompson AT tread tires and the accompanying 12" wide Mickey Thompson aluminum wheels as they could be deflated down fairly low and still stay afloat and not come off the bead and offer superior floatation. There was a lot of air space inside the tire that worked well when deflated for sand. Here are a 33", 285x75R16 AT, vs. the 375x55R16, AT. Both tires unmounted at this point. Both E rated.
My problem is i like sand. My problem is I drive a 10,300 pound off-road domicile.
2. To widen the rear track for better stability.
3. To obtain the highest load rating I could find to support that Lance camper, of which most of the weight is added to the rear axle. At that time it was a 3750 pound load rating.
The 16.5" wheels and tires of old were not made to be pressured down. To work with that rim they must have a robust, stiff carcass. But they were called super singles as they had a slightly wider tread and a slightly wider wheel and could haul a heavier load. They did work ever so slightly better on loose ground than the skinny regular truck tire could even without airing down.
If you NEVER plan to air down your tires for any reason, by all means get the .5 wheels/tires as they will haul a heavier load. The so-called super singles for 450/550's noted above still use only the E rated Mickey Thompson carcass.
Alas, my SS's are not made by M.T. anymore and I am on the hunt for some new shoes. Here is what my latest research has revealed:
No company stocks what i need. There is not a sand suitable super single wheel already made that will work. So, I'm going to have Stockton Wheel make me four, custom made wheels. These will have 1/2 inch solid flat steel centers with a 10" wide version for the front axle with a 6.25 inch backspacing to work with my slightly lifted 2001 Dodge. All the commercial wheels I can find have a 3.5 inch to 4.5 inch B.S. This puts the scrub radius too far out on the spindle for me: and also for the rear of the front fender opening. So many of these driving around destroying their front wheel bearings as the load is way out on the spindle. For the rear, it will be two 11 inch wide wheels with the same 6.25 inch B.S. Why these numbers? I'm trying to squeeze the most floatation I can from all four wheels/tires and still have the ability to carry the load and steer. The rears will be about 6 inches narrower of track than I have now when it all goes together, making the track fit better grinding down some jeep trail.
I searched for tires first. I'm not having wheels custom made without having the tires that will fit said wheels. These were the ones in the running:
Cooper Discoverer S/T MAXX
LT315/75R16
load range E
sidewall black
Approved Rim Width: 8 -11 inches
measured rim width: 8.5 inches
Section Width: 12.5 inches
Overall Diameter: 34.45 inches
Tread Width: 10 inches
Max load: 3860 pounds
tread depth: 18.5
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Nitto Trail Grappler M/T Mud Terrain
LT315/75R16
Load Range E
black wall
Diameter: 34.8 inches
tread depth: 20/32 inches
section width: 12.83 inches
min/max recommended wheel width: 8.0 - 11.0 inches
Load range E
Load max: 3860 pounds (less for dual application)
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Kumho Road Venture MT
315/75R16
black sidewall
tire diameter: 34.50 in.
section width: 12.30 in.
Tread width: 10.00 in.?
min/max recommended wheel width: 8.00 - 10.00 in.
Load range E
tread depth: 21/32 in.
Max load: 3860 pounds.
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All this leads me to believe that all three tires were made by the same tire maker in China. Note the up tick in the load capacity from 3750 to 3860. That's comforting.
I'm leaning toward the Coopers. They should fit. They are fairly quiet for such an aggressive tread tire. We have a similar version of the Coopers on Jeanie's 2011 Grand Cherokee with good results.
I have been driving at low pressure on sand for 40 years. You get a feel of what setup you need to make it work.
jefe
'01.5 Dodge 2500 4x4, CTD, Qcab, SB, NV5600, 241HD, 4.10's, Dana 70/TruTrac; Dana 80/ TruTrac, Spintec hub conversion, H.D. susp, 315/75R16's on 7.5" and 10" wide steel wheels, Vulcan big line, Warn M15K winch '98 Lance Lite 165s, 8' 6" X-cab, 200w Solar