I don't know about the XR's but I have 9000 miles not kilometers on a set of Marathon Pluses 700x32's including a Southern Route this year without a single flat. Just lucky, but I made sure that they were pumped up each day. Ran over a lot of glass and rough roads. I have them on both of my tandems and my other touring bike. They are heavey and a real pain to change on the rims I have Mavic 217's. I ran Conti Top Tour's before which are a good tire, but they defintely changed when they went overseas and were no longer made in Germany. Just a question for the first poster what weight were you carrying? I try to keep my load below 50lbs and a lot less if possible, but water adds up - but I tour with guys who carry what seems like impossible loads at times.