Right now I've got some 16.5x8.25 rims on my truck, and they are not wide enough. I want some rims in the 10 inch wide range, but don't know weather to go with 15's, 16's or 16.5's. I'll outline my thoughts on each of these: 15's : Pros -- have the largest selection of tire choices and the tires are cheaper. Cons -- Have to have steel wheels is a custom offset of 3.5 or less. I don't want to do massive grinding to the caliper. The tires available for 15 inch wheels are almost all 6 ply (load range C), and I'm not sure if thats enough for a heavy truck. 16's: Pros -- a larger wheel with a safety bead, don't have to grind calipers, tires available with a variety of load ranges, all the way to E. Cons -- limited tire selection and PRICEY tires for what are available. 16.5s: Pros- large selection of tire sizes, even 42 TSL's use the 9.75 width. And most of the tires are in the 10 ply range. No grinding of the calper needed, and plenty of space for mud and other crap to be easily washed out. Cons -- No safety bead so airing down will be limited to 20-25psi. Most tire prices are a bit more than the 15's. I wheel mostly on trails and sand, but the trails inlcude lots and lots of rocks. Not the fluffy boulder type of rocks, the small nasty volcanic rocks that like to destroy tires type of rocks, which is why I am concerned about the load range of the tires. The heavier load ranges have stronger sidewalls right? Another reason for considering the load range is because of the weight of the truck, and the fact that it occasially tows a trailer (under 5000 pounds though). RIght now I'm leaning towards the 16.5's because of tire choice (and the ability to go to 42s' without wanting to change the width of the wheel) and the heavy load rating. Generally I don't air down all that much for fear of shreding the sidewalls on rocks. Airing down for the sand isn't that big of concern right now, I'm doing pretty well as it is with the narrow wheels at 25 psi. My choice is mostly between the 15's and 16.5's, and the determining factor is load capabilty. If the 15's are strong enough I'll go with them, otherwise it'll be the 16.5's. Any opinions? I'm not real concerned with them sticking out too far, I'll put a flexible roll-type fender flare on if I have to.