ayceejay
Guru
- Location
- Rural Quebec
If a bike has a chain ring and a chain that connects it to a cog in the back wheel and doesn't have any gear options by way of a derailleur it is stuck or fixed in that one gear ratio until such times as the chain ring or cog is exchanged for one with a different number of teeth. If the rear cog that is attached to the wheel has an interior thread that is fixed but has some bearings between it and the cogs teeth allowing it to move against the flow freely but is fixed going forward this is known as a "freewheel" if there are no bearings in the cog meaning that both forward and backward movement is tied to the movement of the chain ring. this is known as a "fixed' or 'track' cog. Modern terminology insists that one system is a single speed and the other a fixie.