kdouville Posted March 3, 2021 Share Posted March 3, 2021 Hi folks. Been researching for some time and now am asking for some first hand advice if it is out there on single rear wheel axles. Mainly stability and hub strength. I have a 1982 Toyota Sunrader 18' that is slated for a 4WD conversion. Currently has a foolie. Considering a T100 or Tundra rear semi float for width and the stout diff, but it's still a semi float. Do you have experience with a single wheel rear axle and can comment on stability? How about lessons learned about the semi float hub on a single wheel or full float conversions? Maybe you didn't go the Toyota route but put Dana's in? Before I pull the trigger and drop a single wheel rear axle in I am looking for advice from those behind the wheel of similar rigs. FYI, I am a long time Toyota hobby mechanic but new to RV's. I am probably moving both cab and camper shell over to a 1984 long bed chassis. I have considered and read about full float theory, single spare convenience, diff strength, challenges with conversions to rear disc brakes. I am planning a light build but we all know how that goes. Thanks so much in advance! Quote Link to comment Share on other sites More sharing options...
fred heath Posted March 3, 2021 Share Posted March 3, 2021 Weight over the rear axle will determine if you can go with singles. Strongest tire that will fit inside the wheel openings is rated for about 2K pounds per tire. So weight on rear of coach has to be less than 4K. Might be easier to swap to your 1984 chassis and go from there. Quote Link to comment Share on other sites More sharing options...
linda s Posted March 3, 2021 Share Posted March 3, 2021 When you go to single tires your not limited to a 14 inch wheel. 15 to 16 inch wheel on a 4x4 will greatly expand your load tire load limit. Linda S Quote Link to comment Share on other sites More sharing options...
fred heath Posted March 4, 2021 Share Posted March 4, 2021 True in theory. Your wheel wells and bump stops will determine how large a diameter tire you can use and still maintain safe clearance and function. 27” diameter is about the largest you can go and still fit into the factory openings. Doesn’t matter what size wheel you use, the 27” measurement remains the same. Quote Link to comment Share on other sites More sharing options...
linda s Posted March 4, 2021 Share Posted March 4, 2021 Thought he said it was a 4x4 conversion. Lift makes room for bigger. Linda S Quote Link to comment Share on other sites More sharing options...
fred heath Posted March 4, 2021 Share Posted March 4, 2021 Wheels still have to fit into the body cavity. If you measure the width of the wheel well from front to back the tire diameter has to be at least 1” smaller than that measurement. You also have to take into account axle travel in a bottom out situation. You don’t want to have your rear tire crashing through the coach. The factory 185’s are about 25 3/4” in diameter. Look inside your rear wheel wells to give you an idea of how small that opening really is. If you jacked your rig up like a monster truck you could get away with any size tire you want. My research shows 27” is about the max you can use. Quote Link to comment Share on other sites More sharing options...
Genshie Posted March 4, 2021 Share Posted March 4, 2021 (edited) If you haven't already, read my 4x4 Sunrader conversion thread. In it I address going to single rear wheel on the original Toyota 1 ton full floater rear axle. I had Lenny at Motorsport Tech in Reno, NV make me a set of wheel adapters for the 1 ton axle so I can convert from the old 1 ton 6 lug bolt pattern to the modern 6x5.5 Toyota bolt pattern. These adapters keeps the same outside wheel track as the original dually, and I am running E rated BFG all terrains on 16" Land Cruiser rims. After 6,000 miles over frozen Canadian tundra, the deserts of Nevada and some light 4wheeling in the Sierra Nevada, they've been absolutely bomber. If you already have the 1 ton axle, I highly recommend this route. Otherwise, if you have to source a new axle and want to keep the Toyota bolt pattern, an FZJ80 Land Cruiser (1993-97) is a great option, as it's a full floater with disc brakes. You'll need to cut off the coil spring perches and replace with leaf perches, and the pumpkin is a few inches off center, but that shouldn't matter. With the amount of weight these RVs carry, I do not recommend a semi-float rear end off a T100 or Tundra. You don't want all that weight on a single bearing that holds your entire rear axle shaft in the housing. That's why these RVs got recalled for the "foolie" axle; it was a huge liability that eventually ended all production of Toyota RVs. Good luck! k Edited March 4, 2021 by Genshie Quote Link to comment Share on other sites More sharing options...
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