I am looking to replace the stock factory burnt out POS tires on my truck. I need load range E, but I want the biggest tire possible. I found a 285/75-16 BFG All-Terrain in load range E, but it says they are for a 7.5-8.5" inch rim. I would like to put them on my stock wheels, but I tow a 12,000# toy hauler. Also the 265s in E suggest a larger rim than factory, would I have a problem running 285s on stock wheels while towing?

IMHO, 265 is the max if you know you'll have a load on them.

you are asking for trouble towing that heavy with a 285 on a stock wheel, although you may get a response like " i have done it with no problems". Yet. I would not trust this config with my family, but to each their own. I would stick with a 265 if you must use the stock wheels.

unless you are making up for it with a programmer already, you would notice a pretty good loss of power towing uphills as well.

I'm fine running 265's on stock wheels. I believe the stock rims though labeled 6" are actually wider. I feel the 265's larger size.