Spoke

A spoke is one of some number of rods radiating from the center of a wheel (the hub where the axle connects), connecting the hub with the round traction surface.

Spokes can be made of wood or metal. Some types of wheel have removable spokes which can be replaced individually if they break or bend. These include bicycle and wheelchair wheels.

(incidentally... old bent bicycle spokes are sometimes kept in toolkits; they are useful for unblocking plugs etc.)