Freewheel - Wikipedia

Sprag clutch - Wikipedia

Cold forged Fits 1/2in and 1/8in chains New and unique removal notch pattern

Fixed Gear Tri-Diamond Single Speed Bicycle Freewheel 14t/16t/18t/20t, Bicycle Freewheel (20t)

The London Freewheel - Wikipedia

Bicycles/Maintenance and Repair/Freewheels and Cassettes

File:Freehub vs freewheel hub.PNG - Wikipedia

Retrofitting electric or manual freewheel hubs?

Single speed freewheel 16t threaded,30 point engagement Inner diameter=34mm,screw thread=B1.37*24 Tooth thickness=1/2*3/32,up to 9 speed bike chain 8

DRIFT MANIAC Single Speed Bicycle Freewheel 16T 17T 18T BMX Freewheel Sprocket 60 Clicks Nickel Teeth

Ratchet bottom bracket idea, discuss.

File:Freewheel.jpg - Wikipedia