Strange tire wear?

Hi all, I've been running these Cooper Discoverer AT/Ws for the past 50,000 miles or so and I love these tires. That said, they don't seem to be wearing normally. They're wearing more in the middle than on the outside, which would suggest overinflation, but the shape of the tire when looking at it appears to be underinflated. You can see in one of the pictures what I mean- the middle of the tire looks like it's sunken in like it's underinflated, but it's this same middle tread that's worn significantly more, like its been overinflated. I drive a lot pulling a trailer, maybe this has something to do with it? and I check my tire pressure regularly, keeping it about 35-35 psi cold. The max for the tire is 44psi cold.

Any thoughts/ advice?

 

What size are they? I have the ATP3s and I've found running more like 32 psi for better mileage and even wear. I have a completely different tacoma of course... Try a chalk test?

 

Yeah I really should do the chalk test thing. I've got the stock TRD size 265/70R16. Seems a lot of people run lower PSI than the door sticker too now that I'm looking into it. I never gave it much thought til recently. Never had wear issues til now. Just seems strange that if I'm overinflating that they'd appear sunken in the middle like they're underinflated, unless they balloon outwards that dramatically when they heat up?

 

Classic over-inflation. That's my vote. The treads on the sides are also wearing unevenly. See how the leading edge on every nub on the outer edge the front tires is making contact and the rear edge is not? A chalk test would make it more obvious to you but I can see it in your pics. I've got the same problem and am running low pressure for awhile to even them out.

Not my preference. I like the ride better on over-inflated tires. Less resistance. Thus why I have the same problem you're having. Being an AT tire, this problem becomes even more apparent.

 

Thanks guys, sounds like I need to do the chalk test and probably end up airing down a bit.

 

It' funny, I have the same issue. I discussed this with discount tire and they said the tires need to be rotated every 4 to 5 thousand miles to alleviate the odd wear. I've noticed my tires like 30psi.

 

^^ I rotate religiously every 5k. And that's been enough for the first 40k miles on my Michelin Defenders. But once I hit 40k, I've noticed I now get some uneven wear as I approach the next 5k rotation. It's clear to me that 4k rotations would be ideal now.

Lesson-- rotate your tires every 4-5k.

To the op-- if that second pic you posted is on the front, I'd suggest rotating ASAP.

 

I just did a rotation actually and they are moved to the back now. I've been good about rotating my tires every oil change (5k) until about halfway through last year when they started getting away from me. We were overwhelmed with buying/ renovating our house and starting the farm and I was on the road a lot for shows and time for rotations kept being put to the back burner. Things are stabilizing now so I should be back on track.

 

Used to work at discount. Rotate 4k if you tow weekends and run 35-36psi while towing run 32psi empty. But to me it does look like slight over inflation. still pretty decent for 50k miles

 

Anyone know what the proper rotation pattern is for our trucks? My dealer told me last week they Leo hem on he same side. Just swap front to rear on same side.

I wondered what the reason was for that and not switching sides so they're spinning in both directions.

 

Looks like cupping on the outside of the tread, if I remember correctly that’s an alignment issue, excessive camber. Someone smarter chime in.

 

The rears should be moved to the front without swapping but the fronts are switch right to left, left to right and move to the rears (obviously)

 

I agree with Minn, I always thought that's the way to do a rear wheel drive vehicle 4 wheel rotation- bring the rears straight up front and criss cross the fronts on their way to the back. If you rotate the spare in its different obviously, I'd do that with the Jeep which helps spread the tire life around but the truck doesn't have a matching spare wheel unfortunately.

 

I probably am due for an alignment too, never done one yet. I was hoping to spring for 5100s all around soon so I figured I'd wait til after then.

 

Might as well put the new shocks in then get it done. I did some pretty agressive fast offroading and thought id be fine to wait 2 weeks to get an alingment... Ate my dynapros on the insides from 9/32 to .5/32 in about 500 miles lol...

 

I'm not smarter. But I agree cupping can be an alignment issue. But I also think something similar happens when running overinflated on the front. When we turn the wheel, the vehicle's forward momentum causes the tire to "roll" or tip/lean to its side, thereby allowing the front edge of the treads on the side to grab pavement-- the same tread that is not making contact when the truck is rolling straight.

As we roll through a turn and then back to straight, the side tread that was grabbing on its leading edge raises back up due to the tire again being aligned with the direction of forward momentum.

Kinda hard to explain. I don't know if I'm making sense. But I think this type of wear is more common on taller tires and especially AT tires where there is more space between the treads. It can be mistaken for an alignment problem. By airing down, more of the surface will be in contact with the pavement and less roll will occur and/or the entire (front and back) of that particular tread block will make contact and wear evenly.

This issue (like the OP's second pic) is a little different wear pattern than cupping.

 

Wheel width can also play a roll in tire roll

 

Yes over inflation but also people dont realize when they tow a trailer and weight on the rear increases it actually changes the camber on the alignment when the front end raises which also changes the Toe also so strange alignment issues can show up..

 

Lack of rotation seems to be the problem. Rotate every 5000. You rotate front to back in a cross pattern. Passenger front to driver rear, driver front to passenger rear, driver rear to driver front, passenger rear to passenger front.