Tire cupping on 2018 TRD off-road at 45k

I've got tire cupping on all tires of my 2018 TRD off-road at 45,000 miles. The suspension was inspected and no issues identified. The shop inspected the shocks and didn't see any leakage or obvious problems but they are recommending replacement because shocks going bad are the most common cause. What do you think - should I go ahead and replace all the shocks without a directly observable issue with them (save for the presence of tire cupping) or should I be looking for other possible issues?

 

Did you have the alignment checked? Are you on the stock tires? Do you rotate frequently? 45k is way early to need new suspension.

 

Did they check your alignment? Like actually put the truck on an alignment rack and check numbers?

 

They didn't actually run the alignment. I told them that I've driven it on some rough trails, and they said that they wouldn't recommend doing an alignment now because it would need to be done anyway when the shocks were replaced...

Edit: Tires are cooper discoverer at3

 

Yea go to another shop.. They are trying to hose you.

What tires?

 

Still need to go through a hair of troubleshooting before blindly throwing parts at it.

I think that cupping is telltale suspension problem (or balancing) too, but I would at least verify alignment before springing for new coilovers.

 

Thanks. I forgot to mention that the tires are cooper discoverer AT3s. Sounds like consensus is that I should get a second opinion before shelling out the $$$

Edit: the shop said they felt it on all four tires but by my eye its most obvious on the front two.

 

I agree it is most likely not suspension, not if it is all 4 corners. Your truck would need to bounce very noticeably for it to be suspension. I would buy a tread depth gauge for $5 at auto store and measure different spots to confirm the condition first. A second opinion is also warranted.

https://atlanticmotorcar.com/casestudies/tire-wear-tire-cupping-causes-and-correction/

 

Coopers, never mind. They were worn out 42k miles ago.

 

To be honest I don't know a lot about them but they were supposedly the replacement tire from the dealer when I bought the car 10k miles ago.

Second opinion and check alignment?

 

Yeah for sure... my front two were cupped, now on the back, from driving on a sht alignment for too long.

 

Thanks. Nothing aftermarket and no plans to do so.

edit: stopped by a local mechanic shop a few minutes ago and they agreed that replacing all the shocks at 45K miles without a clear issue didn’t make sense. Now I have an appointment with that mechanic to inspect/second opinion for Friday. Thanks all

 

Update!

I brought the tacoma in for a second opinion and their diagnosis is:

Rack and pinion bushings are totally shot.

They think that the suspension looks fine.

This seems to make a lot more sense to. From what I understand, this could explain the tire cupping. I was also driving my wife's car yesterday, and when going back to the tacoma I noticed that the steering feels jerky and with variable resistance. I suspect this had just developed slowly over time and I hadn't noticed.

Anyway, worn rack and pinion bushings seem to make a lot more sense to me as the cause here. Do ya'll agree?

 

I think the only part of an alignment the steering rack would affect is toe and your toe out of adjustment can cause cupping. Only way to confirm would be to have your alignment checked. Also unless you're on bigger tires and out wheeling a lot, 45K miles for rack an pinion bushings seems low but its not unheard of. If you have someone that can help you, you can easily inspect your steering rack bushings.

 

I am curious. I have cupping too on the outer edges of my tires. I have a lift and newer coilovers. It’s just the front for me. Rotate and balance the shit out of them and have had alignment done several times at a couple different shops that understand lifted Tacoma’s and the alignment needs. Haven’t been able to figure out mine yet.

Sounds like you don’t have cupping from all 4 corners but you possibly rotated and the cupped tires went to the back? That is the only explanation I can think of if they are saying its caused from the rack.

Let us know what they find if anything else.

 

wow you got that many miles on that rubber?

 

nah the tires were supposedly new when I bought it which was 8000 miles ago…

 

What was it doing?

My tires are still fat with tread but the outer edges look to be cupping a bit and they are loud as fuck, like howling loud. I can feel a tiny bit of vibration as well. Everything still feels tight I've had cars with bad shocks before and it isn't that. Alignment tracks straight on the highway. Sound doesn't seem to change when turning so not a front wheel bearing.

For those of us who aren't mechanical what are we looking at in that video? Is that stuff not supposed to be moving when he wiggles the steering wheel etc?

 

No, shouldn't move as much. Bushings will always have some deflection especially when under load but should be minimal on good bushings. What you're seeing in the video is what is circled in blue and red below, the red circles being the bushings themselves where the blue circle is the steering rack and the green circle shows the inner and outer tie rod assemblies that goes on the ends of the steering rack.

 

Thanks

Anyways I figured out what happened with mine, they aren't cupped but the guys who rotated them did it wrong.