Not too sure about this whole conversion thing. I guess I'll have to ride one and see, but I'm really having trouble seeing how there could be that big a difference between wide 27" or 700C tires or 26" for that matter. Or maybe I'll step off the bike with crazy 650b diameter irises and say "Now I understand!" My concern is that 650b is yet another fad that will end up seeing a bunch of beautiful old road bikes turned into something they weren't meant to be. Surely that happened enough already with the fixie craze. On the upside, maybe people could take all those drewed fixie frames, add canti mounts and turn them into 650B's, or 6-fixie-B's, or...