The pair of Schwalbe Marathon XR 26x1.6" tyres which I have on my winter commuting bike won't seat properly. The previous pair of the same model were fine. In fact I liked them so much that I bought this extra pair some time ago when I discovered that Schwalbe had discontinued this model. They're folding tyres, with a kevlar bead, and it seems that the bead is a little too short, which produces one or two low spots on the tyre, so I'm not rolling on round wheels and the ride is a bit lumpy. I hoped they'd settle in, but I've done a few hundred miles and they haven't stretched. I've also tried taking them off and trying to stretch the bead, and have blown them up hard to greater than running pressure. I'm about to give up on them and buy some different tyres, but can anyone suggest something I haven't yet tried?