Originally Posted by npoak
It's not the jockey wheels. It's the freewheel and the ability to coast. You stop pedalling, you coast....you loose your momentum much fast on a freewheel'd bike than on a fixed gear bike.
Okay, I get what you're talking about now. I just wouldn't refer to that phenomenon as "momentum", because it's not a closed system; so long as you're constantly pedaling (which is a given on a fixie, and an optional choice on a freehub'd bike) you're contributing energy to the system that's extraneous to the inertia & velocity of the bike.