Tire lug "cupping": alignment or suspension??

Hi everyone. This is my first post. I browsed the suspension posts and didn't see anything similar, but this still might be partially or fully redundant w a prior post and I apologize if that's the case. I'm also an amateur mechanic, at best, when I'm at my peak game. So please be easy on me!

I have a 2016 SR5 5.7L double cab w TRD package. Within 2-3 months of buying it, I installed:

- 275/70R18 Cooper STT Pro muds
- 1.25" Rugged Ridge wheel/hub spacers
- MotoFab leveling kit w 3" coil spring spacers and 2" leaf spring spacers
- Zone Offroad differential drop kit

I had the wheels aligned (presumably to stock specs) after mounting the new tires, and then I installed the other parts and had the wheels aligned again.

I have about 24k miles on the Coopers and the outside lugs are really starting to wear unevenly ("cupping", so I'm told), to the point where the noise on the road is becoming really annoying and my > $300 tires are slowly getting trashed.

I've gotten two diagnostic opinions from the local professional and wannabe mechanics I know: the wheels need to be aligned (again) or the shocks and/or coil springs need to be replaced with adjustable ones to account for the leveling kit lift. I believe the current shocks are Bilstein 4600s.

Does anyone have advice that might help me decide which diagnosis I should address? Thank you in advance for your expertise.

 

Welcome to the forum from CO. Sorry you had to join due to an issue. The experts will chime in soon. And don't worry, I don't know anything about cars; folks here are not high and mighty nor elitist. You should also start a new member intro post so we can get to know more about you and this good looking truck of yours.

 

you failed to note how often you rotate.

 

Thank you for the welcome, COMiamiFan, and thank you for your response, jberry813.

I rotate my tires every 5k miles, including the spare, which has the same Cooper tire mounted on a matching TRD wheel that I replaced the OEM spare wheel with. I keep my tires at about 45psi.

jberry813, do you suggest fixed or adjustable shocks with or without coilovers?

Thank you all for your input, I appreciate it.

 

Thank you again for your reply.

I increased tire size from stock 255/70R18 with the 275/70R18 Coops, and may have mistakenly interpreted information in the following thread as stating that increased tire pressure was appropriate w larger tires. I just started inflating to 45psi last week, hoping it would alleviate some of the wear on the outer lugs, but had always maintained 35psi before, so I don't believe the previous cupping/scalloping is from the recently increased psi.

 

I always run 32-35 psi. Never had problems. Rotate at 5k. BTW. Nice looking ride.

 

My first thought would be the spacers. My second thought would be the shocks. Consider removing the spacers and replacing the shocks with Bilstein 5100s on the top setting. You can add 1 coach builder shim per side to get back up to the 3". You'll be much happier with the ride, put less wear on your components, and will probably have more alignment room. With those spacers, you're probably close to your camber limits if you have stock UCAs.

$.02

 

I've been getting some cupping as well on my Toyo AT2 extremes.. but only 1 tire where i failed to rotate until like 8k mi lol. I have kings all around and they are pretty much new so not my suspension causing it. I've been running about 45 psi though.. do you still recommend 35 psi for E rated tires? But wouldnt over inflated tires just cause the middle to wear more? Im thinking it could have been due to a not so great alignment the first time around.