After reading extensively about 650b wheels, I gave it a go on my 2001 Titus Switchblade to give the old girl some new life. My setup is a CK/Stan's ZTR front wheel, XFusion Velvet fork, and DT Swiss 190/Stan's ZTR rear wheel.

First, I think the 650b concept is fantastic. Even being in "winter shape" (read: out of shape) I was faster by far with the 650b setup than I ever was with my 26" wheels on the 'Blade.

However, a problem: I'm having tire rub on the arch that joins the seat stays at the top of the rear triangle. I have about 5mm of clearance there, but whenever I go over a fairly small drop (8 inches or more), I can hear the tire knobs rubbing on that arch. I'm not a big guy either (170 lbs).

I'm running a 2.0 Quasimoto at about 35 psi in the rear, FWIW.

Any ideas on solving this little issue? Any help is most definitely appreciated, as I don't want to go back to 26" wheels!