But a couple of weeks ago I noticed severe cracking on the sidewalls of the rear tire--severe enough that I was worried. (I've been riding bicycles for over forty-five years, and used to ride and repair motorcycles as well, so I've dealt with tires a lot.) The front had some small cracks, but the rear bore cracks that extended one-third of the way around the tire!
I took some photos and emailed a note to Schwalbe USA by way of Bill Laine at Wallingford, where I'd bought the tires. Bill is a great guy, and his store is one of my "go to" online shops. He forwarded my message to Schwalbe, who emailed me a form to fill out. We went back and forth a bit, with Schwalbe claiming that the cracks were only "cosmetic," and that anyway they had been caused by underinflation.
This pissed me off, as the cracks were both long and deep, and I have had old tires, such as came with used bikes I've bought, suddenly bulge out because of sidewall cracking and subsequent thread damage. Also, I never underinflate my tires: I run them between 80 and 90 psi, and Schwalbe's recommendation on the sidewall lists a range of from 55 to 100 psi. And the front, which I run about 5 psi less, was much less badly cracked--within the comfort range for me.
So we went back and forth some more, and Schwalbe finally wrote that the cracking did not affect the tire's functionality, but that "Regardless, we still offer replacements as a company courtesy so a tire will be coming your way." And then referred me to a post of the late, great Sheldon Brown's about tire cracking...where he wrote of cracks on the tread, not on the sidewall.
I found this pretty off-putting, but took the tire anyway, and mounted it this afternoon. I am hoping that it was a one-time issue with the batch of tires the original came from, or that perhaps, as Marathons aren't well-known in the US, that it was a stale-dated tire, and not representative of the line--which has, after all, a stellar reputation.
The clock starts today on the replacement tire. We'll see what a summer of harsh sun and hot roads do to it. I hope it works out, because I surely do love the way these tires perform--but I can't afford to throw them away half-worn.
Maybe some fixie punk out there will want the old one for skidding....
See update: seven months later....