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"The rear wheel of a freewheeling bike is just as much a flywheel as the rear wheel of a fixed-gear bike."
Yes that's correct, I agree that's an oversight on my part.
But on geared bike: Bike momentum does not carry through drivetrain onto you as you can freewheel. If you stop pedalling, the freewheel kicks in. If you then want to stop, you have to brake
On fixed wheel: No freewheel. So the momentum of the bicycle gets carried forward into you via your legs. So either you relax if you want to slow down, and let friction/weight of your legs do it's job, actively resist with weight/muscle strength by standing up or get bucked off the bike.I find by timing things you can use a little bit of this momentum. If you are slowly rolling but still going you can use it to restart, on a freewheel not so much. That's of course my subjective experience...physics may prove me wrong.
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JWestland
@ffm
Because the momentum of rear wheel keeps the rest of the drivetrain moving (EDIT: actually the momentum of the whole bike keeps the rear wheel turning, which keeps the drivetrain turning). Why is that particularly relevant?
But the momentum of the rear wheel on a freewheeling bike isn't "let go" by freewheeling any more than on a fixed-gear bike. You lose speed due to wind resistance and bearing friction in both systems. The rear wheel of a freewheeling bike is just as much a flywheel as the rear wheel of a fixed-gear bike. The only difference is that on a fixed gear bike you have to maintain the momentum of the drivetrain as well, whereas with gears you stop it with your legs. The fact that you don't even have to think about stopping it on a geared bike is probably indicative of how little momentum the drivetrain is carrying compared to the whole of the rest of the bike.