some quotes to start...
Jeep said:We have put super singles on many HD trucks. We use Alcoa and if you watch the offset you can get one wheel that will work on both ends of the truck as they can be ordered reversible. I do not know if Alcoa makes a wheel with your required pattern. I have had Canadian Wheel Industries supply me with shells and I would install the centers on odd ball applications, I just got a set of wheels for one truck running 53" Michelin XZL's from Stockton Wheel and they were cheaper than buying shells, laser cutting centers, and building them myself. They were built to specs I provided and fit great. If you set your track width properly you will not be adding any extra stress, you may be reducing stress by reducing the rotating mass of a set of duals. You will increase driveline stress as the tire size grows in diameter and gearing is not compensated for.
Good luck, great project,
haven said:"can I put the rims 'wrong way around' on the rear?"
Here's what that looks like
The Mitsubishi Body Builders Guide says the dual rear wheel extends out about 18mm, about 3/4 inch, wider than the front wheel, on each side. Removing the inner rear wheel will subtract about 3/8 inch (the thickness of the wheel where it mounts to the axle) from each side of the axle, making the rear and front wheels line up pretty closely.
The Mitsubishi Body Builders Guide for FE and FG models is located here
Of course, removing two wheels and tires from the rear axle will reduce its carrying capacity by half.
Bajaroad said:By my calculations, the front axles are 6.9 inches wider (per side), but the rear tires stick out 3.7 inches more than the front - subtract 0.4 per side for the disk thickness if you were using only one stock rear wheel.
This leaves you with about 5" more offset from the hub mounting surface compared to stock. This offset is said by some to be potentially catastrophic to the hub, but others use single rears without problems. My feeling is there is some truck load at this offset that places no more stress on the hubs than the stock setup with the GVWR. It might be 1000lbs or it might be 10,000lbs. If anyone has details on the hub bearings (hub dimensions), I will volunteer to do a simplified analysis. There are many forces at play on these bearings such as trust and torsional loads when the truck goes through a turn and brakes, so one would hope there is a large safety factor built into the hub.
If I go with single rears then I will be inspecting/lubing my hubs more frequently than not.
Based on my potentially flawed calculations and design, an 8 inch wide wheel is a good choice for single wheel setup. This custom wheel would need about 3.7 inches of mounting disk offset for the front and rear to have the same track. Below is a drawing of the wheel with 285/75R16 tires (33in dia). I am not sure if these actually fit the front without fender modification, as I suspect the plastic fenders may need to be flared out to accept the extra width (11.6in) and extra 1.0 inch diameter. Using this wheel in the back, the extra offset from the hub is about 3.3 inches. This is the difference between the centerline of the single wheel to the plane between the two dually mounting surfaces. If you use a 10 inch wheel with bigger tires you can get the offset just below 3 inches, but your track will be off by about 0.7 inch.
Jeep said:On the trucks we convert the front wheels are generally moved out a bit which would alleviate any interference, and the rear wheels are generally moved slightly inward from where the outside of the dual wheel is so in perspective of hub and bearing loading you would be increasing the load on the front and decreasing the load on the rear. You are removing some rotating unsprung mass by removing one set of wheels at the rear and unless you are seriously upgrading the tire capacity you cannot carry as much weight on the rear which would again reduce hub and bearing stress. Now how much bigger of a tire can you put on without having negative effects seems to be more of a little trial and error combined with a little engineering.
For an extreme example we remove tandem duals on hydrovac and water trucks and install 48"tall x 31" wide floatation tires. Throw 20 000-30 000 pounds on the back and operate in 2' of mud ranging from clay to muskeg in consistency. At that point breakage is much more reliant on operator ability rather than engineering and componentry, and they really don't break that often.
Tom_D said:Does Fuso N.A. approve any super singles? I talked with Darrin in the spring and so far they do not approve and for FG/FE or FM series.
The example of Auzzie Cantors is interesting but these trucks always seem to be pretty light weight (as is the one in the picture). My camper is usually loaded close to MAX GVWR on any extended trip. I know at least one FG that is above GVWR empty!
A broken hub in the middle of NWT would end up as an incredibly expensive nightmare. If you are a commercial outfit or a weekend warrior then the options are different.