No offense but putting 33’s on a 5.5 rim wont increase diameter. The belting on the tire doesn’t allow that to happen. What does happen is that narrow rim doesn’t allow the tread to fully contact the ground. Lowering air pressure too much to try to achieve that heats up the sidewalls alot. And heat is your tires enemy. 285’s on 16 7 is fine. Done it forever. Run over a newspaper on a flat hard surface and adjust pressure so all of tread is visible on the paper. Every rig is different and running them at max pressure does two things. Covers the tire shops butts and sells more tires. When was the last time you had bald shoulders on a tire?