What's Causing Tire Cupping

[FRV]

Jeep Brain Trust,
On the road headed out west from NC for camping/overlanding etc.

2021 JLUR. Bought new. Now 27,000 miles. Manual trans. Ursa Minor camper top. 2.5" AEV lift. Long range America aux fuel tank. Stock 33" KO2. Tire rotation every 5000 miles. Front end alignment after lift installed. Tires normally inflated to 35-36 for pavement.

Felt shimmy yesterday above 60mph on interstate. We have no interstate at home. Stop at discount tire in TN for rebalance. Nice folks. Helpful. But they found tire cupping. I felt it with my hand. All the tires.

We discussed what it could be. No real idea. We had alignment when I installed the lift. Tires rotated very 5000 miles. AEV dual sport lift had correcting geometry. Good components. Reputable.

Thoughts on why tire cupping?
Looking for some insight.

Continuing on to NM, Colorado, Utah. Maybe I'll see ya out there.

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[jludave]

Thoughts on why tire cupping?
Looking for some insight.

Bad wheel/tire balance.

Bad shock.

 

[Discount Tire]

Jeep Brain Trust,
On the road headed out west from NC for camping/overlanding etc.

2021 JLUR. Bought new. Now 27,000 miles. Manual trans. Ursa Minor camper top. 2.5" AEV lift. Long range America aux fuel tank. Stock 33" KO2. Tire rotation every 5000 miles. Front end alignment after lift installed. Tires normally inflated to 35-36 for pavement.

Felt shimmy yesterday above 60mph on interstate. We have no interstate at home. Stop at discount tire in TN for rebalance. Nice folks. Helpful. But they found tire cupping. I felt it with my hand. All the tires.

We discussed what it could be. No real idea. We had alignment when I installed the lift. Tires rotated very 5000 miles. AEV dual sport lift had correcting geometry. Good components. Reputable.

Thoughts on why tire cupping?
Looking for some insight.

Continuing on to NM, Colorado, Utah. Maybe I'll see ya out there.

I typically look at 3 things when it comes to cupping issues. Lack of rotating and balancing, bad shocks/struts, and alignment.

How long ago was the lift installed?

 

[StartedWith97TJ]

@FRV I also had cupping around 20k miles on my 21 JLURD. I was also following the 5k tire rotation plan. I did an immediate tire rotation (including spare) and have kept doing rotations every 2-3k miles. So far so good. I think some of the off-road tires just need frequent rotations.

Good Luck!!!

Keep Jeep’n

 

[FRV]

I typically look at 3 things when it comes to cupping issues. Lack of rotating and balancing, bad shocks/struts, and alignment.

How long ago was the lift installed?

5000 miles ago. All correcting geometry brackets and shocks as a kit and an alignment after.

 

[FRV]

@FRV I also had cupping around 20k miles on my 21 JLURD. I was also following the 5k tire rotation plan. I did an immediate tire rotation (including spare) and have kept doing rotations every 2-3k miles. So far so good. I think some of the off-road tires just need frequent rotations.

Good Luck!!!

Keep Jeep’n

Thanks for the info.

 

[FRV]

Bad wheel/tire balance.

Bad shock.

Thanks. One wheel needed balancing. Shocks appear to be in good shape.

 

[FRV]

On the interstate now. Much better after the wheel balance. It occurs to me the cupping could have taken place before we installed the lift kit. We were overloaded previously with the Ursa Minor top and all our gear.

 

[Discount Tire]

5000 miles ago. All correcting geometry brackets and shocks as a kit and an alignment after.

Hmmmmm.........Once cupping starts, it's almost impossible to correct.

@StartedWith97TJ is spot on. Up your rotation schedule and adjust air pressure down 3 lbs (if feasable). That should help square up the tread pattern wear. Wouldn't hurt to re check your alignment as well.

 

[Maverick909]

i find that every BFG KO tire i've ever had cupped. there is no getting away from it sadly.

typically bad camber angle, bad shocks, bad ball joints. you can chalk test your tires and see how flat they're running. If its a good solid pattern then start doing ball joint testing and check camber angle

 

[Headbarcode]

35-36psi is a bit on the high side. I'm with Discount Tire on this one. Try dropping the pressures by a couple pounds. It may help with evening out the tread wear, and also the shimmy.

 

[garykk]

I try to rotate the KOs at 2500 miles, last JK I traded had 43k on the tires and they were still good.

 

[VKSheridan]

Bad shocks mate.

Without dampening the sidewall flex becomes perpetual motion which in turns make the tread touching the road alternate between concave an convex resulting in cupping. Rotation just increases the number of tires indicating the issue.

TLDR: Bad Shocks

 

[Old Jeeper]

Jeep Brain Trust,
On the road headed out west from NC for camping/overlanding etc.

2021 JLUR. Bought new. Now 27,000 miles. Manual trans. Ursa Minor camper top. 2.5" AEV lift. Long range America aux fuel tank. Stock 33" KO2. Tire rotation every 5000 miles. Front end alignment after lift installed. Tires normally inflated to 35-36 for pavement.

Felt shimmy yesterday above 60mph on interstate. We have no interstate at home. Stop at discount tire in TN for rebalance. Nice folks. Helpful. But they found tire cupping. I felt it with my hand. All the tires.

We discussed what it could be. No real idea. We had alignment when I installed the lift. Tires rotated very 5000 miles. AEV dual sport lift had correcting geometry. Good components. Reputable.

Thoughts on why tire cupping?
Looking for some insight.

Continuing on to NM, Colorado, Utah. Maybe I'll see ya out there.

The instigator is often a tire out of balance and in days gone by tires that are out of round. Also failing suspension components.

Shocks Failed or failing


The shock is to the tires and suspension the same that a Steering Stabilizer is to Death Wobble. In other words the shocks job is to mitigate the vertical loads and inputs. This makes it critical that the tires are balanced because that is the origin of erratic input and if the shock cannot mitigate it then the result is cupping.

A weak shock and or an out of balance tire will cause a tire to 'bounce' as it goes down the road and every bounce take a bit of tread off until what time you get cupping.

 

[FRV]

That's good info. I can see I should have been more specific. Cupped edges in all five tires is what we have.

My present hypothesis is the damage was done before I put the AEV lift kit in around 20,000 miles. I think I was running the 33" KO2 AT under-inflated on the pavement. With the tires balanced yesterday almost no shimmy at guest speed but the damage is done. I'll finish this road trip out west then replace the tires.

the fox shocks only have 6000 easy miles on them. I gues one could be bad but is that likely?

Is my hypothesis reasonable or this wishful thinking? What is the best way to diagnose this when I get back home before I install new tires?

thanks for all the input and suggestions.

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