general problems of the 2008 Mercedes Benz S550

We were traveling home and our tpms indicated a tire failure. The psi starting dropping rapidly. We took the tire off and found that only 4 " of rubber holding the back sidewall together on the tire. I then inspected the other tires on the car (which were purchased and installed at the same time) are showing signs of failure as well. All of the tires are 255-40-r19 we had a family of 4 in the vehicle at the time of the incident.

Michelin pilot sport a/s plus 255/45zr18 99y as+ installed on 2008 mercedes S550. Tires tread is "chunking" with 18,000 miles of use. Purchased from costco. I have contacted costco. Was told it was "normal", complained it cannot be, we negotiated back and forth on an adjustment. It wasn't satisfactory. I was offered for a discount price the "new" version of the tire, I. E. Pilot sport a/s 3. I have read the other complaints on NHTSA site. They are similar to mine. I spoke to 4 different costco employees, three different michelin yet, I could not fine anyone at costco or michelin that can assure me with an official michelin statement the the problem has been corrected with the new pilot sport 3. I will not pay to have new tires installed at a discount and have the same thing happen again. These tires are a potential safety hazard.

The tire tread on the michelin pilot sport a/s plus shreds or crumbles. Michelin calls it "chunking" and said it was due to the compound used to make the tire. The compound has since been modified. This problem occurred on my girl friend's 2009 mercedes c-series sedan and all four tires were replaced in or about November 2012. I noticed the same problem occurring to the front tires on my mercedes S550 at just over 24,000 miles of use. The tire has a 45,000 tread-wear warranty. The tires were purchased in November 2010. The michelin dealer and michelin acknowledge this is a known problem. The tread splits or cracks at the sipes and falls off, affecting traction and possibly risking a catastrophic failure. Michelin said the problem occurs on only certain model vehicles and does not intend a recall. These tires were recommended by michelin for my vehicle, but it appears they may no longer recommend it. They no longer recommend or make them for my girl friend's vehicle.