Have ordered a 2015 GMC one ton CC SRW SB 4x4 truck. It comes with Michelin LT265/70R18E tires that are rated at 3525 lbs for a rear axle of 7050 lbs. Although I should be OK with stock tires, I wouldn't mind a little extra capacity cushion. In checking other tire manufacturers the only other size that I have found without going to extreme size jumps (which my stock rims probably wouldn't support anyway)or 19.5" is the LT275/70R18E rated at 7640 lbs for an extra 230 lbs of capacity. Does anyone know of another 18" tire that jumps up significantly in capacity without radically changing size and diameter?Thanks!

Check out TOYO. I don't know about 18's but some of their 17's tires (AT's for one) are about 400~500# better than more common rated tires.

gregchambers wrote:Have ordered a 2015 GMC one ton CC SRW SB 4x4 truck. It comes with Michelin LT265/70R18E tires that are rated at 3525 lbs for a rear axle of 7050 lbs. Although I should be OK with stock tires, I wouldn't mind a little extra capacity cushion. In checking other tire manufacturers the only other size that I have found without going to extreme size jumps (which my stock rims probably wouldn't support anyway)or 19.5" is the LT275/70R18E rated at 7640 lbs for an extra 230 lbs of capacity. Does anyone know of another 18" tire that jumps up significantly in capacity without radically changing size and diameter?Thanks!do yourself a favor before you spend any money on a guess. Weigh the truck and TC Then figure out if its just tires or if it is 19.5s and tires.

While I totally agree with Buzz's advice and have given it myself regarding getting the rig weighed, the question then becomes: how much of a safety margin should a person go for? If the rear of the truck/camper weighs 6800 lbs and his current tires have a capacity of 7050 lbs technically the tire capacity exceeds the weight.... Personally, it's not enough for me.I am just wondering what others think is enough of a safety margin?

I to would be interested in what others consider a reasonable safety margin. In doing research on tires I spoke with the manager of a well known nationwide chain tire store. Although he would be happy to sell me a new set of tires and also would give me a trade in allowance on my existing OEM's, he stated that LT tires are down rated because as truck tires the manufacturer knows that they will be worked hard and likely overloaded. He recommended that even at full capacity I would be fine. LT tires used on DRW setups are down rated slightly because there are times when only one tire carries the full or the majority of the load. Not sure I'm on board with his "go to the limit" theory but it is interesting.

I was within 5-10% of my rated tire capacity when towing with the TC loaded up and I had the WDH cranked harder to offload as much of the tongue weight from the rear as possible. With the 19.5" wheels, I no longer count everything I bring with me and use normal WDH settings. The wheels are heavier which required a shock upgrade from OEM, but handing was better with the 19.5's even with OEM shocks that had 85K miles on them.

Truck Tire Capacity | Good Sam Community

Wheelholder
Explorer
Jun 14, 2014
You might want to look at American Racing Daggers. My 16 inch rims are rated for 3800#, if I remember correctly.
billyray50
Explorer
Jun 13, 2014
According to Alcoa website there are some 17 x 8 forged aluminum rated at 3750.
Bedlam
Moderator
Jun 12, 2014
OEM Ford 18x8 alloy max out at 3590 lbs. I have could not find ones with a higher rating for my truck without going to the 19.5's. The OEM steel 17x7.5 were rated for less...
smooth1
Explorer
Jun 12, 2014
I have some American Racing 17" aluminum wheels rated at 3800lbs each. I looked around for a while and this was the highest rating I could find without going to a 19.5". Toyo & Nitto has some tires up near the 4000lb range. Has anyone found any 17" to 20" wheels rated higher than 3800lbs other than 19.5's?
jimh406
Explorer III
Jun 12, 2014
I understand the theory behind steel being stronger, but the fact is that we really should be looking at the actual rated values. I'm running OEM 19.5s on my F450 now, but I am familiar with the different ratings of wheels Rickson sells and those values aren't that extreme. They list the weight rating per wheel at 4500 for aluminum vs 5000 for steel.
billtex
Explorer II
Jun 12, 2014
Typical cold rolled steel has yield strengths ranging from 30 ksi – 150 ksi, and ultimate strengths ranging from 50 ksi – 200 ksi.

T6 6061 Aluminum has yield strengths ranging from 15 ksi – 70 ksi, and ultimate strengths ranging from 30 ksi – 90 ksi.

So, there is some overlap, but in general, steel is ~2x stronger. So for wheels that are commercially available, steel wheels will be stronger for any given size than aluminum wheels. While aluminum is generally 1/2 as strong, it is 1/3 as heavy. So the strength-to-weight ratio is higher for aluminum. If aluminum is “strong enough” for your application, you can save some weight. The challenge for those of us carrying heavy truck campers is we are limited to what we can fit under our trucks and getting the strongest wheel available to fit that space.(Fit = not only the physical space, but mating components as well; hubs, brakes, etc.).
Hope this helps, Bill
Bedlam
Moderator
Jun 12, 2014
Bedlam wrote:
Mike and Terry Ann wrote:
Sorry for going off the topic, but how do you fix the finish on an aluminum wheel where the wheel weight has been.

Most alloy rims have a clear coat finish. If the finish is damaged, it has to be re applied. If the the finish is in tact, you may be able to clean it up with multiple wax or polish applications.
Bedlam
Moderator
Jun 12, 2014
Mike and Terry Ann wrote:
Sorry for going off the topic, but how do you fix the finish on an aluminum wheel where the wheel weight has been.

most alloy rims have a clear coat finish. If the finish is damaged, it has to be re applied. If the the finish is in tact, you may be able to clean it up with multiple wax or polish applications.
Bedlam
Moderator
Jun 12, 2014
billtex wrote:
billyray50 wrote:
billtex wrote:
As you are buying a new truck, it would be cool if the dealer would just swap out the tires for you...don't know if they will do that.

Another thing to consider; steel wheels are rated higher than aluminum. See if you can get steelies from a 1 ton SRW.

Let the dealer know what you are planning for your truck, maybe they will work with you.
Most dealers are clue-less about actually using trucks...you may have to educate them.

Good luck, B

Most steel wheels are not rated higher than true forged aluminum. At least that's what I was told by 3 wheel companies. Was told my 17"x 8 forged aluminum were stronger and rated higher than steel.

Not likely...look at material properties for forged aluminum vs. steel. Big difference. You would need a alum wheel ~ 2x the size (thickness) of steel to have = strength.(Ever see a commercial truck w/alum wheels?)

Another thing to keep in mind is failure mode. Aluminum will fail catastrophically, steel will deform (and can be safely repaired).

Having said that; you can certainly get (forged) aluminum wheel of the proper rating to carry a TC.
But the steel vs. alum is something to keep in mind when wheel shopping...

There plenty of aluminum wheels choices for large trucks. It's whether the owner spends the money over steel:

http://www.peterbiltparts.com/wheels-and-hubs/wheels/aluminum-wheels/

My personal experience with off-road machines has been much more favorable with alloy rims over steel. Not only are they less unsuspended weight that has to be controlled, but they have not deformed on me like steel. Yes, I have destroyed an alloy rim due to rock hitting the the bead. but I have twice as many steel ones with with bent centers because they could not handle rock and tree crawling where you put severe lateral as well vertical forces into work.
billyray50
Explorer
Jun 12, 2014
Not an expert. Just quoting what they told me when I inquired on steel wheels when I wanted to increase wheel rating. Stated the wheels I had on truck were stronger than most aftermarket steel in 17" size.