Hubs

Hubs are the heart of your wheels, containing the bearings and axles that connect your bike to the road and convert your pedal strokes into revolutions of the wheel. Your choice of hub also determines what kind of gearing you can run. Road bikes that use multiple gears need a cassette hub, a freewheel system that lets you change various cassettes of cogs. Track bikes use a fixed-gear hub that only allows for one cog at a time, and don't allow for any kind of freewheeling. Most hubs have sealed bearings to fend of rain and dirt, but some high end track hubs still have open bearings. It's also important to note the number of holes in your hub, which must match your rim for spokes to be laced properly, and the width is correct for your frame.