The Kevlar ones have DoubleDefense, the wire ones RaceGuard puncture
protection. My guess is that DoubleDefense weighs more and negates the
folding bead weight advantage. Nice to see that the XR is back in a
different guise (I got the last two 50x700C from Riv), though the
Mondial doesn't come as wide and sounds like it has beefier puncture
protection, which in my book is a drawback.
Gernot "I don't get flats [and when I do, I don't mind them]" Huber