this post may show up elsewhere, I had typed in my post and my computer shut down just as I was ready to hit enter. anyway, I own a 2011 sonata, gls model, bought new, it has 21,000 miles on the car and tires. about 2000 miles ago the tires started to get noisy so I took it to my dealer to diagnose the problem. After supposedly looking at the tires the mechanic reported back to the service adviser that the tires (ALL FOUR) had cupping (flat spots). they said that the cause was because I hadn't rotated the tires. this is total BS. So they rotated the tires (at my expense) and the noise became much worse when the back tires were moved to the front. Incredibly, the back tire were cupped worse than the front tires. The car now sounds like some sort of off road 4 wheel drive truck. I talked to an old timer in the tire dept. at the local BJ's who said in his 40 plus years experience, cupping is caused by suspension problems or improper balancing, neither seemed to be a problem on our sonata. I am about to do battle again with my dealer about this but my question is: Has anybody had the same problem or is mine unique? I am afraid to buy new tires until I find out what caused these tires to cup.
P.S. the tires are Kumo standard oem

 

I had a problem of cupping on a 2011 GLS even with rotation at 6,000 miles. Normally cupping is due to not rotating tires; I was surprised to see this happen so fast on mine. The cupping was not that bad with low noise only on certain roads. I now have a 2011 Limited 2.0 Turbo with 18” wheels and 7,000 miles rotated at 6,000 miles and no problem at all. If you did not rotate at least in 10,000 miles you ruined the tires and should get new as no way to fix this.