Tire wear help needed

[MountaineerTom]

I have what I guess is cupping on the tires that were on the front of my Jeep. 31x10.50-15 BFG KM2’s. Some blocks of the tread are worn down more than others. They make that weird humming sound now. When I installed my lift 2 years ago I did the toe alignment and got it good using the thread here that tells how to do it. Marked the forward lower control arm bolts and put them back to the same spot after loosening them for the lift. The one thing I hadn’t done is rotate the tires, until two weekends ago. They were making the weird humming sound for a little while too before the rotation, when they were on the front. Tires were put on just a few months before the lift. Off the top of my head I don’t remember how many miles I’ve put on the tires and I don’t have the jeep with me to look in my maintenance book to confirm, but I’d guess 15-20k. Way more than I should have without rotating tires, I know. The rears have worn great.

My question is did the cupping happen because of my lack of rotating or could it be something else like caster or shocks?

I had OME socks that came with my kit for about a year, then swapped them out for Rancho RS5000x’s about 1 year ago. I got 2 new tires to replace the cupped ones with and I’m going to move the cupped ones to my pack mule trailer, just wondering if I should have something checked with the alignment (like caster) at a shop before putting the new tires on. I know I’m going to stay on top of my 5k rotations, that’s for sure.

 

[xxdabroxx]

My Baja claws did it too, I think its called scalloping. I’ve rotated mine since and it’s getting better but I think it comes down to not rotating often enough.

 

[Rick Flair]

My Baja claws did it too, I think its called scalloping. I’ve rotated mine since and it’s getting better but I think it comes down to not rotating often enough.

Yep. Your front tires move not only in a sweep as you turn, but in a arch as well meaning they are moving on multiple planes so they will cup if not rotated to the back on a regular basis.

 

[Daryl]

Rotate your tires at every oil change.

 

[MountaineerTom]

Ok, sounds good. I know to rotate them, I just got bad about putting it off and then forgetting to do it. LOL Will be doing better at rotating them now.

There is only one on the ground right now on the left rear (was previously on the right front). The left front is on the spare. I'll have those two tires replaced and then hold onto the cupped/scalloped one for my trailer since it will not seen nearly as much use as the jeep.

Thanks for the help.

 

[pagrey]

I ran BFG KMs for 60,000 miles, they do that. I had a total of seven KMs given to me, even with regular rotations they all did it. I visit a local used tire shop all the time with a huge inventory and every high mileage KM2 has that high low BS or feathering going on. You can sipe the blocks to help but even with regular rotations they are going to wear funny. It's just those huge blocks in my opinion.

 

[bobthetj03]

Nature of the beast with most mud terrain tires. Frequent rotations will slow the cupping down, but eventually, they will sing. I put 45K on my KM2's before I couldn't take it anymore and got KO2's.

 

[toximus]

What pressure are you running?

 

[MountaineerTom]

What pressure are you running?

28 psi on a day to day basis.

While on the outer bank I’d drop them down to 15 psi or so while on the beach. I left them like that even on the road between the beach and where we‘ve stayed. Over several week long trips over the last 3 years, maybe 100 miles worth at the most.

 

[AndyG]

You rurnt 'em. -50 points for lack of rotation , and not following the forum maintenance pledge.

 

[Goatman]

Do you have wheel spacers or rims with odd backspacing? This can cause the tires to scrub every time you turn the steering wheel. They can push the tire out past its camber setting.
The fact that mud tires are normally softer than normal highway tires also let's them wear in a odd pattern too.

 

[MountaineerTom]

Do you have wheel spacers or rims with odd backspacing? This can cause the tires to scrub every time you turn the steering wheel. They can push the tire out past its camber setting.
The fact that mud tires are normally softer than normal highway tires also let's them wear in a odd pattern too.

No spacers. 15x8 wheels with 3.75 backspacing. I’ve always had A/T tires on vehicles, theses are the first set of mud tires I’ve ever had. I’ve always heard they wore quicker. I guess I just need to do a better job of rotating.

Thanks to all for the inputs.