Rotors, brake dealio, whatever that thing big lumpy thing is called--down there about where the 90o valve stem from the BMW dealership--was whacking it, before they rotated the new stem some more, anyway, that's what I'm talking about. I just sent for a set of Bike Effects stems, and figured to replace them both anyway. Guess I haven't been riding "at speed," cuz it hasn't failed yet. (The dang California Highway Patrol, though, they think I was riding at speed.) Hope it holds up for a couple more weeks. Got a new set of PR2's waiting at Roseville Yama for the rain to stop.