A, B, or C cup?

[Stanley Crewell]

Now that I got you to look at the post I have a question about why my tires appear to be cupping. In the attached photo you can see the inside of the tire on every other lug is warm to a much greater degree. Just noticed this on the spare after the last rotation because with tires on the vehicle you can't really see the inside well. Not sure how long it's been going on and the tires have 36,000 miles on them with a five tire rotation every 5000. Vehicle goes dead straight down the road with no vibration and haven't noticed an increase in road noise possibly because it has happened over time. Any info is appreciated.

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[PWillette]

Firstly...B for me

For 36k miles those look pretty dang good to me. What pressure are you running?

 

[Stanley Crewell]

Firstly...B for me

For 36k miles those look pretty dang good to me. What pressure are you running?

35 most of the time. 39 for Long highway trips.

 

[Newbie]

A, B, or C cup?

 

[PWillette]

35 most of the time. 39 for Long highway trips.

Have you tried the chalk test to check your contact patch? Not sure what your running for tires but I had to drop my 37 Nittos down to 30psi to get the contact patch where I like it. Roughly 15k on them and they are wearing very good.

 

[Brian_B]

That does look odd but not sure it’s cupping.

 

[Nate Train]

D+ cups only.

Actually, that's a lie. I'll take any boobs.

 

[RobWTX]

Per ChatGPT (uploaded your pic), this is what it spit out.


Most likely causes (in order):

1. Too much negative camber
   • Common on Broncos, especially Sasquatch or lifted/leveled setups
   • Causes the inner shoulder to carry most of the load
   • Often drifts after lifts, wheel offset changes, or suspension settling
2. Toe out of spec (often toe-out)
   • Scrubs the tread instead of rolling it
   • Accelerates inner-edge wear
   • Combined with camber, it will eat the inside lugs fast
3. Aggressive tread + IFS = lug chopping (“every other lug”)
   • Seen on KO2, Ridge Grappler, Duratrac, Baja Boss, Territory MT, etc.
   • Slight alignment errors cause the tread blocks to oscillate under load
4. Underinflation as a contributing factor
   • Especially if trail pressures are run too long on pavement
   • Increases tread block flex, worsening the uneven lug wear
5. Possible suspension wear (less common unless higher mileage)
   • Upper control arm bushings, ball joints, or tie rods can exaggerate camber/toe issues

What should be done:

• Get a full 4-wheel alignment ASAP
  • Ask for a before/after printout
  • Camber and toe matter more than caster for this issue
• Verify street tire pressures (don’t run trail PSI on pavement)
• Continue 5-tire rotations every ~4–5k miles
• Inspect suspension if alignment won’t hold

Bottom line:
This wear pattern is classic negative camber + toe combined with aggressive tread, not a rotation problem. Once it starts, rotation won’t stop it without fixing alignment.

 

[BroncoAdventure]

Is your Bronco lifted?

 

[Stanley Crewell]

Is your Bronco lifted?

Nope. Non sas outer banks with badlands take offs. 285/70/17's.

 

[Stanley Crewell]

Per ChatGPT (uploaded your pic), this is what it spit out.


Most likely causes (in order):

1. Too much negative camber
   • Common on Broncos, especially Sasquatch or lifted/leveled setups
   • Causes the inner shoulder to carry most of the load
   • Often drifts after lifts, wheel offset changes, or suspension settling
2. Toe out of spec (often toe-out)
   • Scrubs the tread instead of rolling it
   • Accelerates inner-edge wear
   • Combined with camber, it will eat the inside lugs fast
3. Aggressive tread + IFS = lug chopping (“every other lug”)
   • Seen on KO2, Ridge Grappler, Duratrac, Baja Boss, Territory MT, etc.
   • Slight alignment errors cause the tread blocks to oscillate under load
4. Underinflation as a contributing factor
   • Especially if trail pressures are run too long on pavement
   • Increases tread block flex, worsening the uneven lug wear
5. Possible suspension wear (less common unless higher mileage)
   • Upper control arm bushings, ball joints, or tie rods can exaggerate camber/toe issues

What should be done:

• Get a full 4-wheel alignment ASAP
  • Ask for a before/after printout
  • Camber and toe matter more than caster for this issue
• Verify street tire pressures (don’t run trail PSI on pavement)
• Continue 5-tire rotations every ~4–5k miles
• Inspect suspension if alignment won’t hold

Bottom line:
This wear pattern is classic negative camber + toe combined with aggressive tread, not a rotation problem. Once it starts, rotation won’t stop it without fixing alignment.

After seeing this I suspect the added weight of a winch and mount to the front might have caused the slight negative camber.

 

[Brian_B]

Aggressive tread + IFS = lug chopping (“every other lug”)

• Seen on KO2, Ridge Grappler, Duratrac, Baja Boss, Territory MT, etc.
• Slight alignment errors cause the tread blocks to oscillate under load

I learned something from ChatGPT today -- will wonders never cease

 

[stevenstommyboy1]

So typical BFGoodrich KO2 tires, as they age they tend to cup for some reason. Even with rotations and proper inflation known problem on the Ford Raptor forums and been my experience with BF Goodrich KO and KO2 tires and they get really loud as they age and wear.

 

[glashaus]

After seeing this I suspect the added weight of a winch and mount to the front might have caused the slight negative camber.

no comment on the tires.

I believe that I have the same winch mount and have been looking into adding lights to the mod bumper in the locations that you did. I have some brackets coming that I think will work after I do some modifications to them. What brackets did you use to mount your KC lights to the mod bumper?

 

[Stanley Crewell]

no comment on the tires.

I believe that I have the same winch mount and have been looking into adding lights to the mod bumper in the locations that you did. I have some brackets coming that I think will work after I do some modifications to them. What brackets did you use to mount your KC lights to the mod bumper?

I honestly don't remember where I got the brackets. They just melt directly to the modular bumper and stick out far enough to attach the lights.

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