I have Goodyear Wrangler RT/S LT245/75R16 (Load Rated E) tires on my 2007 Chevy Silverado 2500 HD Diesel. The tires are one year old and have 23,000 miles on them. When I left home to go to Sacramento, CA, I noticed a vibration and visited a Chevy dealer in Sacramento to get the wheel balance checked. They said that the sidewalls on all four tires were soft and failing and the tires needed replaced. They pointed out a narrow groove running around the sidewall of each tire. I went to a nearby Goodyear dealer and was told they had never seen anything like this and the tires looked defective. I was told to return tomorrow when the manager was available to see what could be done. I have taken meticulous care or these tires by keeping them properly inflated and rotated. I wonder what the manager will have to say tomorrow.