Cupped tires on 2018 JLUR

[samsjeepjlur]

Hello, I currently own a 2018 Jeep JL Rubicon Unlimited. I owned the vehicle for about a year until I finally gave in and bought some upgraded tires for it. After doing what I thought was sufficient research, I bought 35x12.5x17r BFG KM3’s and Black Rhino Fury wheels while avoiding the cost of an expensive lift kit. After about a year of having these on the vehicle and 25k miles later, I noticed severe cupping/scalloping/chopping (whatever you want to call it) on the front two tires. It seemed to happen pretty rapidly since I had noticed it after it was pretty bad. I’ve been told it sounds like I’m bouncing down the road. I’ve gone to several local shops and they all tell me different things. I’ve been told it could be a shock issue, springs, axels, or that BFG is notorious for this. Also I have a stubby steel Innovative Creations Magnum front bumper installed so it could be the weight in the front stressing the suspension. I can’t seem to find a definitive answer online since it’s not a very common issue. If anyone is educated on this topic or has had this happen to you please let me know what to do. Everything is stock on the vehicle except for the front bumper and the wheels/tires.

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[samsjeepjlur]

Hello, I currently own a 2018 Jeep JL Rubicon Unlimited. I owned the vehicle for about a year until I finally gave in and bought some upgraded tires for it. After doing what I thought was sufficient research, I bought 35x12.5x17r BFG KM3’s and Black Rhino Fury wheels while avoiding the cost of an expensive lift kit. After about a year of having these on the vehicle and 25k miles later, I noticed severe cupping/scalloping/chopping (whatever you want to call it) on the front two tires. It seemed to happen pretty rapidly since I had noticed it after it was pretty bad. I’ve been told it sounds like I’m bouncing down the road. I’ve gone to several local shops and they all tell me different things. I’ve been told it could be a shock issue, springs, axels, or that BFG is notorious for this. Also I have a stubby steel Innovative Creations Magnum front bumper installed so it could be the weight in the front stressing the suspension. I can’t seem to find a definitive answer online since it’s not a very common issue. If anyone is educated on this topic or has had this happen to you please let me know what to do. Everything is stock on the vehicle except for the front bumper and the wheels/tires.

Also I guess I have grown pretty use to the sound/ride of it because I didn’t really notice much until I physically looked and felt the tires. I live in Louisiana so I don’t see any extreme weather and I’ve gone rock crawling in Arkansas a few times since I’ve installed the tires. (Making use of the rubicon)

 

[JeepU4IA]

What air pressure are you running? I believe your tires are E-rated so I would think you should run them at about 30 psi. I run 28 psi on my E-rated Ridge Grapplers and still don't get full traction on the edges.

 

[The Last Cowboy]

How well were they balanced? Large BFGs are notoriously difficult to balance. What backspace do your new wheels have? A big negative offset will change the scrub radius and can cause those issues. Also, how often did you rotate them?

 

[Whiskey 13]

How well were they balanced? Large BFGs are notoriously difficult to balance. What backspace do your new wheels have? A big negative offset will change the scrub radius and can cause those issues. Also, how often did you rotate them?

I concur, large negative offset combined with bad balance and alignment will play hell on any tire.
I have been down that road with balance issues, the e rated BFG's are great when you get a good balance but very unforgiving when out

 

[The Last Cowboy]

The last set of BFGs I ordered for my old Super Duty, I told the manager at Discount Tire to order 8. When he asked why I told him that I wouldn’t accept any tire that took more than 4 ounces total to balance and that I knew that 1 or 2 out of 4 would be that way. He understood as he knew how they are too.

 

[mwilk012]

KM’s are bad and it sounds like you haven’t rotated them often enough.

 

[samsjeepjlur]

What air pressure are you running? I believe your tires are E-rated so I would think you should run them at about 30 psi. I run 28 psi on my E-rated Ridge Grapplers and still don't get full traction on the edges.

Since I’ve posted this I’ve quickly figured out that I’ve been running them about 7 psi over what I should’ve been. Guys over at discount tire told me to run them at 40 psi which is obviously way off. Hopefully that’s the issue

 

[samsjeepjlur]

KM’s are bad and it sounds like you haven’t rotated them often enough.

I’ve rotated them every 5k miles. I believe they were over rotated when I had to get one of them plugged due to a nail

 

[samsjeepjlur]

I’ve rotated them every 5k miles. I believe they were over rotated when I had to get one of them plugged due to a nail

Over inflated*** sorry

 

[samsjeepjlur]

How well were they balanced? Large BFGs are notoriously difficult to balance. What backspace do your new wheels have? A big negative offset will change the scrub radius and can cause those issues. Also, how often did you rotate them?

They were balanced quite well and aligned perfectly. I run Black Rhino Fury’s 17x9.5 which have a -18 offset. Rotate them every 5k miles.

 

[The Last Cowboy]

Yeah, 40 PSI is way too high, even though it’s a load range E tire. Is the center of the tread worn more than the edges? Air them to the recommended pressure on the road and then you do about 12-15 off road. The wheels are a negative offset, so that doesn’t help either, especially if they are wide.

 

[samsjeepjlur]

Yeah, 40 PSI is way too high, even though it’s a load range E tire. Is the center of the tread worn more than the edges? Air them to the recommended pressure on the road and then you do about 12-15 off road. The wheels are a negative offset, so that doesn’t help either, especially if they are wide.

Nope they are worn as much on the edges as they are in the middle. I’ve learned a lot tonight about the proper psi for the tires. Just still worried that suspension parts may be an issue in the future

 

[The Last Cowboy]

Many will disagree, but I don’t like negative offsets and the wide stance look. There will be extra stresses placed on suspension and steering components. Many mods are a compromise of some sort, looks vs capability vs reliability. Everyone has different needs and wants.

 

[samsjeepjlur]

Many will disagree, but I don’t like negative offsets and the wide stance look. There will be extra stresses placed on suspension and steering components. Many mods are a compromise of some sort, looks vs capability vs reliability. Everyone has different needs and wants.

Yeah I only did it because I’ve got a stubby front bumper that I fell in love with and thought it only looked good with a wide stance. I was right but sorta regret it. Based on your opinion, is a lift kit worth it? Or is it too unpredictable based on reliability?

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