[GM4lyfe]

I'm not a tire manufacture so I'm not going to say what does or don't exist or what is marketing or not. They are listed that way for some reason, maybe speed rating.

I do remember when the fourth gen Z28 was offered with tire options, the Z rated and the "touring tires". My friend had one with the touring tires told me that GM limited the car to about 120 MPH. The Z rated equipped car were limited to the 155mph. So if thats true then offering all-season tires won't work on the ZL1 because of speed ratings. Also the handling chartiristics of all-seasons are not the same as a summer tire, for that safety maybe of concern with GM. With that said I take back my last post.