Maybe this is a difference between fixed gear and freehub. The little bit I've used a fixed gear on my SS (a flip flop type hub) or used a spinner at the gym I can see where you can build up momentum to keep you spinning at high RPM. On a fixie behind a derney that's geared low (the bike) I guess you'd have to spin to keep up. On my freehub I spin it out to no resistance and want to reach for that higher gear for the resistance. Without the momentum or the resistance I start bobbing around.