986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Got some new tires

johnsimion · 01-29-2013, 04:27 AM

About three months ago, I decided to change the OEM Michelin Pilot Sports on my 08 Cayman because I was tired of keeping it in the garage all winter long. My car was bought new in April 09 and had only 15K miles, and the Michelins had lots of tread left, so I thought the change was just for my own convenience. I ordered new Bridgestone Potenza RE470s through Tire Rack and presold my old Pilot Sports to a guy who wanted them for racing. When I brought my car to the shop, I discovered that all four Pilot Sports had dry rot. It manifested only in vertical cracks in between each row of tread. They looked great from the side and you really could only see the problem if you looked directly at them. The shop told me they were actually dangerous -- and the shop had nothing to gain by telling me that, so I tend to believe them. I had to cancel the sale of the tires and I refunded the guy's money.

What I discovered is that new Bridgestone Potenza RE470 all-season tires handle MUCH better than dry-rotted Michelin Pilot Sports. Until I changed the tires, I always thought the handling of the car really wasn't what it was cracked up to be, as I could easily spin out. Now I am taking turns at speeds that definitely would have spun me out before, plus I've been driving all winter instead of leaving it in the garage.

What is weird is that the Pilot Sports' handling had never really changed the whole time I've owned the car. They would always slide at a certain turn near my house, and I just thought it was a handling issue with me or the car. The Potenzas don't slide and that particular turn is a blast to take now. Makes me wonder if the Pilot Sports were already dry-rotted by the time I bought the car -- the car having sat in the sun on the dealer's lot for a very long time before I bought it (built Dec 07, sold Apr 09). The shop told me that dry-rot of high-performance summer tires is very common. Sure, they were exposed for 15 months on the dealer lot, but it's been garaged since then. I just don't think they should have had this problem in just over 4 years under these circumstances.

I guess fresh Pilot Sports must really have great grip, but I really cannot imagine that I would have any use for more grip than the Potenzas. Dry rot in 4 years and inability to drive in winter pretty much make it a sure thing that the Pilot Sports were my last set of "summer" tires. My experience makes me wonder if your Continentals also had dry-rot.

01-29-2013, 04:27 AM	#3
johnsimion Registered User Join Date: Nov 2008 Location: Missouri Posts: 112	About three months ago, I decided to change the OEM Michelin Pilot Sports on my 08 Cayman because I was tired of keeping it in the garage all winter long. My car was bought new in April 09 and had only 15K miles, and the Michelins had lots of tread left, so I thought the change was just for my own convenience. I ordered new Bridgestone Potenza RE470s through Tire Rack and presold my old Pilot Sports to a guy who wanted them for racing. When I brought my car to the shop, I discovered that all four Pilot Sports had dry rot. It manifested only in vertical cracks in between each row of tread. They looked great from the side and you really could only see the problem if you looked directly at them. The shop told me they were actually dangerous -- and the shop had nothing to gain by telling me that, so I tend to believe them. I had to cancel the sale of the tires and I refunded the guy's money. What I discovered is that new Bridgestone Potenza RE470 all-season tires handle MUCH better than dry-rotted Michelin Pilot Sports. Until I changed the tires, I always thought the handling of the car really wasn't what it was cracked up to be, as I could easily spin out. Now I am taking turns at speeds that definitely would have spun me out before, plus I've been driving all winter instead of leaving it in the garage. What is weird is that the Pilot Sports' handling had never really changed the whole time I've owned the car. They would always slide at a certain turn near my house, and I just thought it was a handling issue with me or the car. The Potenzas don't slide and that particular turn is a blast to take now. Makes me wonder if the Pilot Sports were already dry-rotted by the time I bought the car -- the car having sat in the sun on the dealer's lot for a very long time before I bought it (built Dec 07, sold Apr 09). The shop told me that dry-rot of high-performance summer tires is very common. Sure, they were exposed for 15 months on the dealer lot, but it's been garaged since then. I just don't think they should have had this problem in just over 4 years under these circumstances. I guess fresh Pilot Sports must really have great grip, but I really cannot imagine that I would have any use for more grip than the Potenzas. Dry rot in 4 years and inability to drive in winter pretty much make it a sure thing that the Pilot Sports were my last set of "summer" tires. My experience makes me wonder if your Continentals also had dry-rot. Last edited by johnsimion; 01-29-2013 at 04:30 AM.