Cupping after 7,000km and dealership doesn't know why

I went through that problem too with 285
Do you have a lift at the moment?
I finally sort of mine all out...

At first, I had a warranty leaf Pack (they added shims into the leaf pack)
that's when I first started noticing a very light, cupping

After getting that done it helped a lot

Next was another problem my needle bearing !! I really believe this was the major cause of it because of the slight tolerances, when the axle moves, it tends to vibrate !! I think this was the major culprit of cupping (always rotate the tires at 5k even cross rotate)

And I always noticed it was the driver side front tire that was taking the damage


So I got the needle bearing done did the egcs and it feels 1 million times better

Still have some cupping in the tire and I'm just going to deal with it till it's bald

 

My 2022 SR5 with the original ToyoA31 have been cupping since new. I call it feathering as I believe it is the same thing. My truck drives as smooth as glass with no vibrations, pulling, or wandering. I now have 16000 miles and tires were rotated every 5000 miles at the dealer. I am westling with getting an alignment but I'm concered they may screw up somethig else trying to address this issuue. I thing I will leave well enough alone and when these tires wear out, I will replace them and then talk to the tire man. On a side note, there is a used car dealer within walking distance to my house. Every Tacoma on his lot, wether it has 5000 miles or 30000 miles, have the exact same feathering on both front tires on the outside treads. And yes, I do rub my hand accross the tires and front to back. LOL. I guess this is just a Tacoma thing.

 

That sounds very high

 

Much pronounced with duratrac. Thing is no vibes , tracks straight. Smooth as butter on highway speeds so I never messed up with the alignment.

 

I won't either.

 

I don’t have a lift. I’m glad your stuff is getting better because it’s annoying as hell.

 

The Tacoma does not weight that much running 35 to 40 pounds of pressure in the rear tires would lead to wearing out the centers. My old Ram 2500 4x4 only ran about 45 PSI in the rears on a tire rated for 80 PSI anything more than 45 PSI would wear the centers when the truck was empty. The Ram weighed just over 7,000 pounds empty. Now if you load up the truck to capacity and are towing adjust more air as needed.

Like another poster said, get a piece of chalk and put a stripe across the tread and drive a mile or two and you will see where the tire tread is contacting the road, if the entire chalk mark is warn away add some tire pressure until you see chalk on the outer tread inside and outside on the tire, when you see that let out a pound at a time until you have even wear across the entire tread contact patch. Do the same with the fronts.

 

To the OP, did you change the rims as well? If so did you change the offset, that could lead to alignment issues as well.

 

It’s the air pressure
Run 34 front and rear
Rotate every 5 k and you should be good

 

Yeah I did all that. Chalk test is what gave me the numbers. 35psi up front and 32psi in the rear

 

Nope, stock rims

 

Air pressure too low for E rated LT tires. Contrary to what feels logical, LT tires, with the heavier sidewalls vis-a-vis the oem factory set need higher pressure to provide the same load support - try 40 all around and I suspect the cupping will stop.

 

No, I can't physically see any cupping. I had the body shop and dealership both tell me about it. I have vibrations in my seat, which lead me to believe that it was a wheel or two out of balance. The tires only have 7000km and I rotated them 2000km ago, I've always been pretty religious with rotations every 5000km.
I'm going to try and get in to see the specialist shop that's local to me to inspect everything. My initial thought (and still is) my suspension has worn out. I want to make sure though before I start dropping big bucks to get it going again

 

Yeah as soon as I get my truck back tomorrow I'm upping the air pressure, getting an alignment and a balance and hopefully get in to my specialist shop to do a better inspection on my truck.

 

That is the craziest thing I've ever heard. 100% worth looking at the alignment numbers to see what they look like. Alignment I did 2 years ago on my truck and not touched it since. Zero cupping/feathering with my tires. Currently running Nitto Trailer Grapplers 35x11.5r17. Put about 15k miles on some Falken MT 285/70R17 and almost have 10k miles on these Nittos. For reference I have Bilstein 5100s with OME 887 springs up front and factory upper controls arms. Also I run about 28 psi all the way around.

 

Most likely the tires weren't balanced correctly. Had this happen to me once with new snow tires I bought. Went to a different shop and some of the balance weights were clocked 90 degs from where they were before. The shop that originally mounted and balanced my tires straight up did a poor job.

 

Normally if you feel vibration in the seat it is either rear tires out of balance or a belt has slipped in the tire or something in the drivetrain is out of balance maybe the drive shaft. Some times you can unbolt the drive shaft and rotate it 180 degrees and that will cure a drive line vibration. If you feel vibrations through the steering wheel that indicates an issue in the front end, tires out of balance, worn suspension parts, a tire belt that has slipped.

Sometimes a vibration can be nothing more than the road surface as well, see if you can find a smooth street and see how it feels, these big dump trucks and box trucks will cause asphalt to become wavy from their weight when they accelerate and brake, the surface will look smooth but it is not and will result in you feeling a minor vibration.

 

I was focusing more on the cupping issue . If you get vibration it’s balance especially if it’s at just certain
speeds. That’s usually a dead give away

 

Seems like an alignment is in order.

 

Chalk test is pointless. It provides absolutely zero useful information.

Cupping is caused by your alignment and specifically toe. Some tires are more sensitive to it than others. Get your wheels aligned ASAP and post the print out. My guess is you will find your toe angle was out of spec.