Weird Tire Wear

[JTrac]

Was visiting my daughter today and my son-in-law noticed some tire wear on the rear passenger side dually set. I am getting some significant cupping on the inside of the outside tire and the outside of the inside tire (I know, but it's the only way I can describe it). No other tire on the truck is showing any signs of anything but normal wear. I have 22K on the truck. I have not felt any vibrations, drifting or any other unusual handling issues. I keep the tires at the recommended 65 psi and they were rebalanced about 6 months ago. They are Michelin's, by the way.

I will take it in to the dealer tomorrow but just curious if any ideas why this would happen. Doesn't seem like it should be possible.

[whjco]

Cupping is not uncommon on dual tires.

[TakingThe5th]

Kuhn-thanks for the tire rotation procedure. My front tires are my newest ones, and I like to keep them fresh, so I like the idea of reversing your procedure. In other words-I'll mount some fresh tires on the left and right outer dual rims, then put those tires on the front. The old front tires then get moved to the inside duals on the same side. Finally the old left inside dual goes to the right outside dual and the old right inside dual goes to left outside dual. The old outer dual tires are then discarded.

OP - this technique would get your cupped tires off the truck sooner rather then later.

If I follow this procedure while replacing my front tires every two years my tires will get rotated out before they get too old and the front rubber will always be fresh.

[fj12ryder]

Kjun wrote:
The left rear out side rotates the same direction as the right rear inside. The same for the right side. The rims are offset and can be used in any position. The tires are directional. If I remember right it would be something like this. (1) Left Rear inside to Left front. (2)Left Front to Right Rear outside. (3)Right Rear outside to Left Rear inside. (4)Right Rear inside to Right Front. (5) Right Front to Left Rear outside. (6)Left Rear outside to Right Rear inside.

Thanks, I never considered that the wheel offset on duallies changes the rotation of the tires. Thanks for the explanation.

[Kjun]

Directional tires are usually for traction. This is controlled by tread pattern that gives them the ability to self clean. Some are directional by design at the job at hand. Off road, all terrain. highway mileage. winter / summer etc. Depending on the design is the way the tire cords are layered. Also the rubber compound. If it has a arrow on it make sure it is in the right direction what ever you have to do. If you want to see cupped duel rear tire visit your local truck stop or check out the 18 wheeler next to you in a rest area.

[Grit_dog]

fj12ryder wrote:

Kjun wrote:
Cupping dual wheel tires is nothing new. when it starts there is no straightening it out. Most causes out of balance, bad shock ,lack of rotation. Tire rotation, inside rear to front, front to rear outside, outside rear to inside rear. If tires are directional move side to side also. If different rims remount.

Why would you move directional tires side to side? Directional means they're designed to rotate one direction. Moving them to the other side would go against the directional design.

You can move directional tires side to side but you'd have to dismount the tires and flip them. That said, directional tires run fine backwards. They are just designed with superior traction in one direction. Mfg don't make tires that blow up if run backwards.....except maybe Firestone, lol.
That said we are talking about HD pickups, of which there are precious few directional tires available unless you're running low pro tires designed more for LD trucks and SUVs.
I've never seen rear tires cup like the OP describes, single or dually. Never seen them cup at all. Rotating to the rear straightens out bad tread wear patterns. Never put a bunch of miles on a truck so far out of balance of broken cords to see that effect either.
But doesn't seem like the OPs problem. New truck no vibration.
But you did have the tires rotated. I'd say the most likely cause is those were the front tires 7k mi ago and you're just seeing them now on the rear.
You can tell if they're actively cupping or feathering by feeling the tread. If the feather edges are "sharp" then it's happening now. If they are dull/ rounded off a bit then it probably happened on the front and is slowly wearing back to flat tread. Which will take longer on an unloaded dually (not much towing the camper in the winter?) than a srw with 2x the weight on each rear tire or loaded up.

[Kjun]

The left rear out side rotates the same direction as the right rear inside. The same for the right side. The rims are offset and can be used in any position. The tires are directional. If I remember right it would be something like this. (1) Left Rear inside to Left front. (2)Left Front to Right Rear outside. (3)Right Rear outside to Left Rear inside. (4)Right Rear inside to Right Front. (5) Right Front to Left Rear outside. (6)Left Rear outside to Right Rear inside.

[fj12ryder]

Kjun wrote:
Cupping dual wheel tires is nothing new. when it starts there is no straightening it out. Most causes out of balance, bad shock ,lack of rotation. Tire rotation, inside rear to front, front to rear outside, outside rear to inside rear. If tires are directional move side to side also. If different rims remount.

Why would you move directional tires side to side? Directional means they're designed to rotate one direction. Moving them to the other side would go against the directional design.

[Kjun]

Cupping dual wheel tires is nothing new. when it starts there is no straightening it out. Most causes out of balance, bad shock ,lack of rotation. Tire rotation, inside rear to front, front to rear outside, outside rear to inside rear. If tires are directional move side to side also. If different rims remount.

[JTrac]

I am not sure how the rotation was done but it makes me suspicious. I do know the guy that wants to do it every 3k miles is nuts. At the prices they charge I could just buy a new set every 30k miles or so. If nothing mechanically wrong is found I think my best option is to get one more dismounted rotation and balance and if nothing is wrong with the tire just drive it and watch the results. In hindsight, I should have done what what the owner's manual says and that is just switch the fronts and rears from side to side. I let someone talk me into something that I didn't need.

Even though I don't think it is an issue I will check the lug nuts tomorrow.

[carringb]

I don't rotate my tires either, other than "flipping" the rear outer tires every 30,000 or so because the outside edge wears faster. I also swap the fronts side to side on occasion.

Cupping indicates something's moving that shouldn't be. Have you checked lugnut torque?!?

I would think you'd feel the vibration if things were out of balance.

[fj12ryder]

So basically all this abnormal wear has happened in less than 7,000 miles. Where did the tires that are showing wear start out originally? I'd be looking at the shop that did the alignment and tire dismounting and rotation. Since it sounds like the wear started around that time, they are the ones I'd be talking to about the problem. Sounds like they screwed something up somewhere.

[TakingThe5th]

This is just a "shot in the dark" thought - did you rotate tires front to rear or did you do a criss-cross rotation? I'm wondering if you are having some cord separation that might have been caused by moving the tires left to right. Just a thought. I'm old school and always keep the left tires on the left and the right tires on the right.

[45Ricochet]

Usually most DRW trucks don't rotate tires, especially if you have nice wheels with steel on the insides. Dismount and mount at 3k miles??? Give me a break. I never did and didn't get that cupping problem. Of course I didn't have Michelin's either
You need to contact Michelin directly and have some photos ready.

[JTrac]

A little history. When I took the truck in for it's first service under the 2 year free maintenance, which includes tire rotation, the service manager told me they never rotate dually tires. I should have questioned it but didn't. At about 15K I took it to a local shop for an alignment and they said I should do a rotation by dismounting the tires since the front and rear wheels are different. There was no abnormal wear at that time. I did that and everything seemed fine for a couple of 1600 mile trips. We drove it about 125 miles yesterday and it still drives normal.

I took it back to the original place that did the rotation and they said I need to rotate and balance again but had no reason for the cupping. I took it to the dealer and a different guy said I need to rotate and that the abnormal wear could be from the heavy load. Go to another tire shop and they said I need to do a complete dismount rotation and balance every 3K miles since it is a dually ($$$$). They thought the cupping happened because that tire was on the front for too long. I left.

A friend of mine who owned a tire shop for many years thinks it could be balance but I feel nothing in the steering wheel. I'm thinking something mechanical but it is hard to say. I do have a set of Air Lift bags on the rear but that should not matter. I keep them at 5 pounds when empty and only run 25 when pulling the Winslow. I'm due for the last of free maintenance from the dealer. I will have them check the shocks, do a rotation and balance and then just watch them. Not sure what else I can do.