I know that you are not alone in your belief here, but I question how a bike that pedals for you if you stop is able to train your 'spin.'? The whole point of single leg drills is to isolate your legs so that there's no down-force to offset and lift a 'lazy' upstroke. The entire concept/function of a fixed gear, is such that not only do you have the downward force of your other pedal to lift your upstroke, but the momentum of the bike itself will do the same if you decide to simply stop pushing.

I can understand how your 'power' may improve with riding a fixed gear simply by the fact that you're unable to downshift, so it forces you to mash instead of turning a higher cadence. But this 'I ride a fixed gear so I know how to spin' idea seems somewhat of a stretch to me. Say you're riding a 48x15 gear on level ground. How many folks are going to be sustaining 120-130 rpm in that gear (i.e. practicing smooth power at high cadence)? And if you happen to be on a slight downhill, then the cadence might come easily, but it's not going to be a result of your buttery smooth 'spin,' but rather a result of gravity.

My question, put more simply is this: If you are riding a bike that is just as happy to pedal you, how does that teach your body to be efficient in smoothly pedaling it?

I'll take my answer off the air.

-Jeremy