PCA SDR

I just pulled the Michelins out of storage to trade out the Yokohamas. While detailing the wheels I noticed that the tires are clearly marked on the "outside" tire wall and are all mounted correctly. As a result when they are installed on the car the tread pattern is slightly different from side to side so that the tires don't present the identical tread pattern to the road. This is noticeable on the outside tread blocks where the slightly curved groove between the block is rounded forward on one side and backward on the other side. It seems like there is no alternative mounting to avoid this. The tires have no markings to identify left or right side installation. They are N4 rated. They were purchased with the wheels from a well known mail order vendor. They were installed on the car only briefly before I put the Yokohamas on for the first AX (just prior the engine blowing). I didn't notice the asymmetry when they were on the car. Is this situation as Michelin and Porsche intended? It obviously doesn't make any difference but it seems like wearing two left shoes. Perhaps a good question for the Trivia Quiz at the Parade.

Tim

This is very common. Same is true with rims, like the Porsche Twist, they twist forward on one side, back on the other. I am pretty sure the major reason is cost savings, but the minor difference in groove direction is minor as long as you keep the BIG blocks of tread on the outside and the smaller on the inside, thus the OUTSIDE labeling. Too expensive to have 4 unique rims and tires, prevents any tire rotation, etc.

Some tires are unidirectional, but that trend seems to be going away, with the inside/outside taking over.

Just my findings, you could ask at the tech session....