Front freewheel

Unlike regular bicycles, a front freewheel can make it possible to shift gears using a derailleur while the rider is coasting if paired with a fixed rear hub or a freehub with a slight resistance in the freewheel mechanism, which causes the chain to continue spinning with the wheel rotation.

[1] Freewheels in bottom brackets have been used on some pedelec and are necessary parts for all mid-drive systems to allow the electric motors to work inside their optimal rotational speed ranges.

It will slip if necessary however, to stop the chain in the event of, for example, a clothing tangle – which could otherwise lead to injuries of the leg by the drivetrain, crashing of the bicycle, or both.

FFS marketing followed Shimano's then-current path of beginning with lower-cost implementations of the system using low tech and usually heavier materials.

The resulting system was substantially heavier than the standard freewheel and, in any event, did not penetrate the market noticeably, although Panasonic, Ross, Schwinn, and Raleigh briefly equipped bicycles with FFS.