Kumho Wintercraft WS71 Tires Cause Vibration

I purchased Kumho Wintercraft 215/50R18 92V WS71 M+S tires on December 16, 2023, and I’ve been experiencing issues since the very first day. Despite having the tires balanced multiple times at different tire shops, the car vibrates and bounces on the road while driving. Every technician I’ve visited has confirmed that the problem lies with the tires.

Most recently, the dealer also acknowledged that the tires have a defect — specifically, that they are out of round during rotation, causing the vibration issue — and said they would file a warranty claim. However, it has now been 10 days, and I still haven’t received any response.

I’m requesting that Kumho speed up the warranty process and replace my defective tires as soon as possible.