First let me say, I've run a lot of Conti Gators, and love them. The Conti Sport contact came on my recumbent, a 20" front and 700c rear. I clean my tires fairly often and last week notice the sidwall rubber where the logo is was detaching. I took the rear tyre off, and upon flexing the sidewall, noticed a crack in the rubber exposing the casing runing the circumference of the tyre. So I then took the front 20" off and it had the same cracking in the rubber..These tires are less then 2 years old and with less than 900 miles, and have been kept in a dark garage out of the sun. The tread has held up well, and few to no glass cuts and no flats, and the tyre rides well, but boy am I unhappy with the cracking sidewalls! I've never had this happen with the Gators. I want issue free tyres on my bikes, so these have been replaced with other brands...