I sold my MTB this winter and don't feel like maintaining one any more. I'd like to do a couple of local MTB races with the cross bike and was looking far a large and hopefully rinch-flat resistent sort of tire. I am using the Maxxis Larsen tire which is decent enough, is there anything that would do a better job in a clincher? I don't think one of those "29-er" MTB tires would be thin enough, correct? I have a regular cross frame with average clearance.