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Cupped tire suggestions

EddieExpedition

EddieExpedition

1/2 ton status
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Here’s the situation, I put on new Toyo open country 31x10.5 about 15k miles ago. I’ve had them balanced a few times due to improper balancing when I bought them. I’ve also rotated them every 5k miles. They are now cupped and cause a pretty noticeable vibration.

I’ve checked all of my suspension components and nothing appears work. Ball joints and steering linkages are tight, new leaf spring bushings were installed 1.5 years ago. Toe is set properly. I put on bilstein 4600 shocks 4 years ago and I’m assuming they’re still in good shape.

Any idea what could be causing the cupping? Worn out springs, truck too heavy for the tires? I’m kinda at a loss for why they cupped and I don’t want to get new tires until I figure out what’s causing it.
 
Almost always shocks are the start of irregular wear and then made worse by imbalance.
Pictures of the tread wear can help identify what it is.
 
I took them in to get rebalanced a few days ago and the shop confirmed my suspicion. I’ll have to grab pictures after the hurricane passes. The wear is more noticeable on the outer edges which led my to think the toe was off.
 
Wear on the outer edges with a sharp edge on the end of the lug indicates a toe condition. Just worn smooth but heavy on the outside edge could be a couple things. Like a lot of caster so it scrubs real hard when turning. These trucks came with quite a bit of you still have stock springs which I’d assume you did with 31s.
 
When you got your alignment what did your camber look like?
When I first got my truck it had a 6 lug 10 bolt and it had quite a bit of positive camber. It liked to wear the outside edge of the tires.
I fixed it using the shims between the spindle and the knuckle.
 
Do the 10 bolt fronts have bushings in the upper ball joints like a dodge 44 does? I had a Dodge once that ate the outsides off the tires because someone installed that bushing in the wrong orientation....same thing, everything was tight but if you looked at it from the front the tires were cocked in ever so slightly.
 
I’ll have to look up the alignment paperwork. I don’t think that there’s a bushing in there, but I could be wrong.
 
Chickntrk said:
Do the 10 bolt fronts have bushings in the upper ball joints like a dodge 44 does? I had a Dodge once that ate the outsides off the tires because someone installed that bushing in the wrong orientation....same thing, everything was tight but if you looked at it from the front the tires were cocked in ever so slightly.
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There’s a sleeve that goes in the upper ball joint that needs to be set to a specific torque upon installation. I think you use a fish scale pulled horizontally in the tie rod hole and it needs to be about 14 ft lbs. I’d need to look it up know the exact procedure. But the factory sleeve is a uniform sleeve. There is an aftermarket one that you can install to adjust the camber.
 
That’s exactly what I was thinking of, I recall something about it throwing the camber off even if it’s the uniform one of you don’t torque it correctly….I’ll look in the fsm tonight
 
Yeah when I did my ball joints I had to buy that special little four-prong socket to set the torque on that sleeve.
 
Bear with me because this may not help but here is a situation I ran into. Maybe this information will provide insight to a different cause for cupping.

I drive about 50,000 miles a year for work so I try to use a gas-friendly vehicle without going electric. I have a 2014 Toyota Corolla which has proven to be one of the best cars I've ever owned. I do, however, go through a set of tires every 12 to 15 months. One year I purchased a set of nice directional high performance tires thinking that it would give me the ability to have more fun on the highway. I found out quickly that the rear end tires CUPPED within about 15,000 MILES. Thinking that it was caused by compromised suspension parts I replaced both rear strut and spring assemblies. I got two new tires for the rear and set about my business. Sure enough, 15,000 miles later the tires were CUPPED. Luckily on the day I was in the shop for the issue with the second set of tires I ran into a man who had previously experienced a similar problem. He contacted an engineer friend at Goodyear Tire and learned that directional tires on my car were ill-advised. He said what was happening is that at highway speeds, air was catching underneath the tire and was forcing the tire off the road a few millimeters and then dropping back down. the tire tread pattern was not allowing air to escape effectively. The tire hitting the asphalt caused friction which caused the cupping. The problem was amplified by my rear end being light and having little downforce. Some vehicles have more downforce in the rear from the factory than others. I guess those fins on the back of Honda Civics do more than look good (lol).

I changed back to regular non-performance tires and the issue went away 100%.

Can you tell if the cupping on your K5 is only happening on the rear or is it happening on all four tires? Apparently the engineer that the man spoke with said that this issue is common on a lot of cars and trucks. He explained that improper tires for a given application can cause this to happen.

Maybe look at the type of Tire you're using and consider changing brands or tread patterns.

Again, this story is my experience and may not relate to your situation but I wanted to throw that out there as a possible Factor.
 
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100% true and happens on every Mini Cooper and pt cruiser.
 
I was wondering if it had to do with the weight of the blazer and camper. Maybe we were running the air pressure too low or the tires just aren’t a good fit for the truck. I can’t tell wether the front or back is causing the issue. I’ve rotated them a few times. Or it could be that we drove on them too long out of balance?
 
EddieExpedition said:
I was wondering if it had to do with the weight of the blazer and camper. Maybe we were running the air pressure too low or the tires just aren’t a good fit for the truck. I can’t tell wether the front or back is causing the issue. I’ve rotated them a few times. Or it could be that we drove on them too long out of balance?
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I'm pretty sure you'll have to get new tires. Regardless, I would recommend getting a different brand just in case the specific brand was causing the issue.
 
That prolonged imbalance will definitely show in tread wear.
 
EddieExpedition said:
I was wondering if it had to do with the weight of the blazer and camper. Maybe we were running the air pressure too low or the tires just aren’t a good fit for the truck. I can’t tell wether the front or back is causing the issue. I’ve rotated them a few times. Or it could be that we drove on them too long out of balance?
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I guess it could be possible that the weight of the trailer could have been pressing down on the back so heavily that it caused the front and to be much lighter thereby allowing the front tires to imperceptibly lose traction with the asphalt.

Is there any way for you to check the tongue weight of the trailer on the back of the blazer?
 
ZombieK5 said:
I guess it could be possible that the weight of the trailer could have been pressing down on the back so heavily that it caused the front and to be much lighter thereby allowing the front tires to imperceptibly lose traction with the asphalt.

Is there any way for you to check the tongue weight of the trailer on the back of the blazer?
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No trailer, he has a slide in pop up camper in his Blazer.
 
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