While I have a Dodge Ram truck, my load is near identical to yours front/rear axle weights. I tried to convince myself that 285/75-17 Nitto Dura Grapplers. Rated to carry 3970# on Hummer H2 rims (made from forged aluminum by Alcoa) rated at 5,000lbs each was enough to support it all. But I was nervous with the poor shape of the roads I've encountered and that the further I'd get from civilization, the worse they got. Definitely did not feel comfortable at speeds 65mph and higher. (and honestly, a big reason for a camper is so I'm not restricted on max highway speeds like towing has)
Then I read the report by Buzzcut having a blow out. He lives near me and we drive the same highway system, so I really took it to heart when he narrowly escaped disaster. I first searched online and found Rickson, a manufacturer who makes 19.5 wheels here in the USA. The price was enough to choke me, so I started scouring craigslist and got lucky; some guy out of Nevada had a set and was willing to meet me in South Lake Tahoe. Got my wheels for a very reasonable and fair price, then headed to my local Les Schwab dealer. I trust them as they have a large commercial tire sales business and wanted their advice. They loved my truck camper rig when I brought it over and they recommended TOYO's. I chose the M608Z tire because I occasionally travel dirt roads and I live in hilly snow country. Well, there's no way I can say I don't now feel safe with these on. Wow! The tires squirm a bit until they are broke in, but any heavy lugged tire will do the same I believe. The sing to me at any speed above 40mph as well, but I just pretend I'm a badasz trucker.
There are a couple things you do need to be aware of if you go this route;
1. They are a TALL combination. A 2 inch front lift was needed for tire clearance, otherwise there was interference when turning the wheel lock-to-lock.
2. If you want your spare to be the same, figure another way to mount it because it's likely not to fit under the bed of the truck where the factory puts the spare. Even if you keep the stock spare, if you ever need to change one on the road, where ya gonna put that big boy after you remove it?
3. They are HEAVY. I'd say at least 50 pounds per wheel/tire combo over the aluminum HUMMER H2 wheels and Nitto tires. I compensated this added weight by dumping my stock spare. The H2 and Nitto wouldn't fit where the spare goes, and I found the factory stock tire to now be past it's prime, age-wise. Besides, these tires, if you damage one, you'll likely have other problems than just a flat tire. Not only are they 14 ply rated, they are deep lugged AND they can be cut for a 2nd tread, there's that much more rubber under the existing tread. Anything pierces that has my attention!
4. Your speedometer and odometer will be off about 10%. A code change can correct it usually, but may cost a visit to the dealership and a charge to set this up for the taller tires.
5. Because they are tall, they affect your power curve. Having a Cummins diesel engine, it was fine by me to lower RPM's at freeway speeds. I now turn 1800rpms at 65mph.
6.This isn't a cheap upgrade. But for me, safety of my family and peace-of-mind for me was worth it. I can take these tires anyplace and not worry about any sort of failure
7. They suck when the truck is empty and the road is wet. I first discovered this making a left hand turn at a 4 way intersection and my rear tire hit the painted crosswalk. Wheel spin, no traction. I've got an open differential, so there is that, but just mild power and turning causes the tire with the lesser traction to loose grip. I'm too afraid to test them on snow covered roads empty but I did with my camper on. Fine for that as I can lock in 4 wheel drive and she's solid.
8. They are harsh when the truck is empty. You know you are driving a truck, that's for SURE!
Hope this helps!
