I was on a group ride with my Maza Prestige (TSX tubing). At one point, we were doing about 24MPH on the flats and the front end of my bike started resonating. I could hear it and feel it in the bars. It only lasted about 20 seconds. We slowed down for a road hazzard and it stopped, and never returned. I have over 50K miles on this bike and this is the first time I've ever experienced this. I checked the frame, fork, wheel and headset and found nothing wrong. The only difference with the bike is: I usally use Vittoria Rubino Pros, but I put Open Corsas on about a week ago. Was this just a case of the right speed on the right road surface? Or, is there something I should be watching out for?