I was grinding up a hill on my fixed gear commuter when the rear wheel went wobbly for about two revolutions, then the tube exploded. It has been pumped up to 110 psi, which is a little higher than usual but certainly not a first on that wheel/tire combination. Furthermore, I had not changed the tire or tube for nearly a year (at least 600 miles), so something should have happened earlier if the tube was installed incorrectly back then. When I later took out the tire for inspection, I could find no defects --- there were several nicks from debris but none that cut right through the casing, the bead seemed fine, etc. Just to be safe I bought a new tire anyway and got home (approx 12 miles) on it without incident. I also checked the wheel and it had an almost unnoticeable wobble, not enough (I would think) to cause the blowout. The hole on the tube was slightly off-center.
The tire was a 700x23 Vredestein Fortezza SE (rated to 160 psi), mounted on an IRO rim. I can't find any indication of pressure rating for the rim, but I would be surprised if they were rated to less than 110 psi.
Any thoughts on what could have caused the blowout?