I don't really understand what you mean by deliberate forward motion or simple descending.
As for pedalling back at traffic light, i presume you mean with the rear wheel on the ground? Can't do it on fixed with the wheel on the ground so no loss, can't do it at all on a coaster brake so no loss.
I don't really understand what you mean by deliberate forward motion or simple descending.
As for pedalling back at traffic light, i presume you mean with the rear wheel on the ground? Can't do it on fixed with the wheel on the ground so no loss, can't do it at all on a coaster brake so no loss.