Front end inside edge tire cupping - looking for root cause advice (2 Viewers)

[grinchy]

So I’ve got cupping on the inside of both my front tires. It is slightly worse on the driver /left side. It’s been going on for at least 18 months, I was burning thru the remaining rubber as the tires have to be replaced anyhow. No rotations since I first noticed it. It’s about as wide as the inner tread block. Doesn’t seem to be getting ‘worse’, meaning the steps stay about the same differential height, obviously the tires are wearing abnormally fast in the affected area.

Details:
35x10.5r17 Kenda RT
Ahc Sensor adjustment about halfway
Running ‘black’ spring rubbers, which is 2nd stiffest of 4 options.
Last alignment was maybe 5 years ago. (Eek)
Roughly 260000 miles, assume original front suspension parts still in use

Gyraline provided current state measurements. My measuring area (driveway) isn’t ideal and was a bit higher on the left side, about 1/4 bubble, so the caster and Camber are a bit skewed. I ran several passes and got consistent values.

Toe -0.7 deg, 0.1 deg
Camber -.4 deg, 0.2 deg
Caster 3.4 deg, 3.2 deg

I’m looking for advice on the root cause of the wear, as I suspect suspension and don’t want to burn another $600 of tires up immediately.

Even though the toe is obviously out FL, I’m seeing same wear pattern and same general magnitude on both sides.

Ideas on suspension items that would cause this? where should I point the parts gun first?

I’ll add some pics shortly.

 

[grinchy]

Pics of the right / passenger side

 

[grinchy]

Left / driver side

Left from a distance

 

[Camotubebender]

looks like you just need to rotate your tires more often

 

[grinchy]

FWIW the set on the rear were on the front for one rotation interval. They are also cupped a little. It’s not getting worse for those since being put in back, and they are wearing evenly across the tread. I didn’t roll them back up front because then I’d have ‘throw away’ wear on four tires instead of two.
It’s the front position that is causing the cupping.

 

[TeCKis300]

Perhaps a few things at play.

Primarily, it looks like you have a bit too much toe out on the front axle.

With 260k miles on the suspension, the front suspension, especially the LCAs, may need some attention as the bushings are probably well worn and allowing some degree of slop.

 

[ravencr]

You should have your toe set to 0 to a little bit positive but a few tenths at most. I don’t know what the ideal camber would be on these rigs, but my guess is up to -.5 would be pretty good for pretty even tire wear. Caster looks good to me. Your toe out and negative camber on the left side is likely the cause of the inside of the tires to be wearing unevenly.

Chris

 

[grinchy]

So toe and camber out on the left side is causing similar tire wear on left and right?

 

[ravencr]

So toe and camber out on the left side is causing similar tire wear on left and right?

Most likely for the car to drive straight, your steering wheel is correcting for it causing both sides to have toe out. The negative camber on the drivers side just makes it a tad worse on the drivers side.

Chris

 

[rlynch356]

Toe in and Negative camber will both do that. could be either or both..

I'd align it with a shop that can do it to factory specs with your lift.
I tend to get mine aligned at least yearly, since well, Rocks do stuff to the alignment