Explain this Tire Wear

[cody c]

It’s been probably 10-15k since I rotated them. But this pattern shows up on the front and rear tires. Tires still have wheel weights on them. Lugs that are black probably have 1-2 32nds of wear more than the others.

I’ve been running them at 35psi on the street, but the tires are rated for 80psi.

When you are running too much pressure, you usually get center wear, the center of the tires bulge out more basically and wear faster. When you have too little pressure, the center of the tire doesn't have enough pressure on it, and the outside edges wear more (as I understand it) and so you can figure out if your pressure should be higher or lower based on how they are wearing. With too heavy of a tire (in terms of rating and psi) your ride may be still too rigid at that pressure though, (for example an E rated tire on a vehicle that would use a C rated tire).

I suspect in your case you are running a bit too little pressure, and the cupping may have to do with worn shocks. you might have just a pinch too much toe in as well from when the were on the front. I've had cupping on every set of geolanders I've had, so I'm not really the best for figuring that out.

The cupping on those tires in my opinion is excessive toe. Inducing excessive toe on this forum as a good thing is widely advised and I don’t subscribe to it.

I set my caster to factory specs which is 2-4* and adjust toe as close as I can to factory specs which is 0.

Make sure your axle and tie rod ends are in good shape and your good to go.

Thats what I've been running, my truck seems a bit touchy, like it wants to dart to the right or left a bit easy, because these are AWD and the driving force is being applied to the front tires ( a force wanting to pull the front of the tires inwards), I believe they may operate better with less toe in, as compared to similar vehicles with RWD.

In a RWD vehicle the car will push itself forward from the rear, the resistance of rotating the front tires will want to pull them back slightly (outwards from front end of tire), any slack in wheel bearings (which you are supposed to have), trunion bearings etc can pull the tires back or outwards, which would be corrected/engineered with slightly more toe in.. Just my opinion, probably the majority would agree though I think.

Toyotas spec for toe is 0, no toe, non at all. All I see on here is people with light steering feel being told to add toe.

I tape measure my toe and error on the safe side and do have very little toe.

I've been going with a bit of toe in, but I think close to zero toe in I will try next. However mine is less than close to stock so not really a fair comparison.

in the 92 manual:

In the 96 manual:

 

[landtank]

Toe was always a big concern back in the day of rear wheel drive cars with bias ply tires. Once radials came out with less rolling resistance everyone went to minimum toe settings

I’m just stating my experience. I’ve had 80s since 2000, my son had an 80 from high school through college so more than 300,000 miles logged between them and not once did I consciously rotate the tires and got more that 60,000 miles out of a set with no weird wear issues.

 

[cody c]

Toe was always a big concern back in the day of rear wheel drive cars with bias ply tires. Once radials came out with less rolling resistance everyone went to minimum toe settings

I’m just stating my experience. I’ve had 80s since 2000, my son had an 80 from high school through college so more than 300,000 miles logged between them and not once did I consciously rotate the tires and got more that 60,000 miles out of a set with no weird wear issues.

And what kind of toe setting you run? minimum i'm guessing

 

[mudgudgeon]

Toe was always a big concern back in the day of rear wheel drive cars with bias ply tires. Once radials came out with less rolling resistance everyone went to minimum toe settings

I’m just stating my experience. I’ve had 80s since 2000, my son had an 80 from high school through college so more than 300,000 miles logged between them and not once did I consciously rotate the tires and got more that 60,000 miles out of a set with no weird wear issues.

You're right. Your toe settings 100% explain that

 

[landtank]

You're right. Your toe settings 100% explain that

I’m sure it’s more than that but it plays a role in it. Also sure maintaining factory Ackermann angles is part of it also.

 

[Surfdc]

Figured i would chime in here because i went through this exact same thing! I was chasing a freeway vibration (whole different thread) and one of the first things i checked was my tires and found this cupping pattern, which was the cause of the vibration. But the cause of the cupping was that my suspension was shot. (the tire is bouncing down the road causing the cupping wear) So in one afternoon, I determined that i needed new suspension, and new tires! . Just replacing the tires will not fix anything.
It has already been mentioned here by the experts to check toe, because that will cause cupping too. However yours is cupping in the rear tires as well, so that makes me think worn suspension. Yes i see you have a slinky stage 1 kit that is not that old, but the icon shocks that kit comes with are soft, especially if your rig is not stock wright! (I have the same shocks). They could already be shot. The good news is icon will rebuild them. under warranty if it's within a year. I had to have 2 of mine rebuilt in the first year.
hope that helps.

 

[LandLocked93]

In case it wasn't mentioned in the detailed analsys, I understand that a matching spare in the middle diagram would move to front passenger while rear passenger moves to spare position.

 

[thatcabledude]

In case it wasn't mentioned in the detailed analsys, I understand that a matching spare in the middle diagram would move to front passenger while rear passenger moves to spare position.

This is how I’ve always done 5 tire rotations. I do it every 5k mi when I change my oil.

 

[LandLocked93]

This is how I’ve always done 5 tire rotations. I do it every 5k mi when I change my oil.

View attachment 3058726

I'll see your tomahtoe, and raise you a tomato.

 

[Tedward]

Have the same tires, stt maxx, with about 40+k miles. Rotated the tires here and there. Had them balanced a few times.
Have the same wear pattern and low speed cobblestone effect with high speed shake.
Long ago I set the toe like Tools R Us spelled out for us.
Tie rod, ends, shocks, bushings, etc. got replaced with new oem before the new tires.
Air pressure has been between 32 and 37 psi.
anyhoos I don't know what or why but got the same uneven wear
Sometimes when dust/dirt is on them you can clearly see the same pattern shown in the op pic.

 

[Outsane]

You maybe able to get the tires shaved to remove the feathering or cupping.

Big rigs get tires shaved, we used to get our race tires shaved for better performance.

 

[Funner]

Shocks

 

[motormayhem]

Have the same tires, stt maxx, with about 40+k miles. Rotated the tires here and there. Had them balanced a few times.
Have the same wear pattern and low speed cobblestone effect with high speed shake.
Long ago I set the toe like Tools R Us spelled out for us.
Tie rod, ends, shocks, bushings, etc. got replaced with new oem before the new tires.
Air pressure has been between 32 and 37 psi.
anyhoos I don't know what or why but got the same uneven wear
Sometimes when dust/dirt is on them you can clearly see the same pattern shown in the op pic.

Hmm yea I’m running 35psi on the street. Maybe I’ll bump it up a bit more. I also get some vibration going down the highway. I’ll see if anything is loose, but I doubt it as the wheel/trunnnion bearings are <20k as well as the all the link bushings. The socks did just recently start leaking so I had those rebuilt, but this has been happening for a year or more. At last check the toe was within spec.

I just rotated the tires, but don’t expect it to address the wear. I’ll admit these haven’t been rotated. But all 4 corners are wearing like this so that seemed strange.

 

[Shipwreck]

So you had the shocks rebuilt. Did you rebalance the tires?
Unfortunately in my experience, once that cupping has occurred, it will not correct itself even after addressing poor shocks and imbalance. The remedy is to have the tires shaved back to round as others have mentioned. But, Hardly worth it for a non-commercial tire.

 

[motormayhem]

So you had the shocks rebuilt. Did you rebalance the tires?
Unfortunately in my experience, once that cupping has occurred, it will not correct itself even after addressing poor shocks and imbalance. The remedy is to have the tires shaved back to round as others have mentioned. But, Hardly worth it for a non-commercial tire.

I haven’t had the tires re-balanced. Might be worth doing. Ya I didn’t have high hopes of fixing it since shaving it doesn’t make a ton of sense. I’m almost wondering if this started after running some rocky trails in New Mexico and chunking out the tread a bit. Otherwise either these shocks or tires are not impressive as things are pretty tight in the suspension.