Hi Troutguy:
Please find below an excerpt from a previous post I made in July of 2012 about LT 285/75R16 Goodyear tires on 16X6.5 inch wide stock GM PYO forged aluminum wheels:
"My Input: My 2007 GMC 2500HD 4X4 D/A CC has put 43,000 miles on Goodyear Wrangler Silent Armor 285/75R16 tires mounted on the stock PYO forged aluminum wheels. These are all terrain tires with "durawall" side walls to resist cuts and have a load rating of 3750 lbs at 80psi. The Tire Rack sells these tires for $244 each. Bought locally they cost about $280 mounted and balanced before tax. Loaded with the camper wet and all gear, I carry about 4700 lbs on the front wheels and 6500lbs on the rear and travel extensively off-road, as well as on road. I average between 14 and 16 highway MPG on my truck and camper, I now have an average of just over 5/32" of tread left on the tires and project to get at least the 50,000 miles tread life advertised by Goodyear before reaching the wear indicators in the tread."
I, in fact, did get 50,000 miles out of those tires and then bought another exact same set of tires. My truck was always rock solid with no sway, wandering, bouncing or other uncomfortable handling on the highway (at speeds up to 90 mph - passing) and on gravel and off road trails. I did have to modify my suspension to carry the weight of the camper so I did not get "rock and roll" off road. It is true that the tires do bow up a little in the center, but, for these tires at any rate, this did not significantly affect tire life.
Based on my experience, 6.5" wide wheels will work just fine with 285/75R16 tires. The problem you will face in going to aftermarket aluminum wheels to get an 8" width is the wheel weight rating seems to top out at 3650 lbs, which is less than the tire weight rating. The stock PYOs can carry about 3800 lbs. Also cast aluminum wheels weigh about 50% more than the forged wheels.
Hope this helps...Terry
