Why is it that road bike tires sidewalls crack and dry out so soon? After only 1.25 years, cracks are noticed right at the seam where the tread ends and the sidewall begins. I have Continental Ultra Race kevlar type tires. I read somewhere they aren't a big deal as long as no bulging or out of roundness is seen. But I wonder if certain brands of tires are better then others. I remember long time ago I had tan sidewall type "gumwalls" and they didn't last long before crumbling away. I wonder if the black chili compounds are better or maybe Bontragers? Maybe you guys wear them out so fast, you don't notice.