BeOne RAW cycle frame
Components 101: Learn the basics about a bike frame before we go all technical.

Components 101: Frame

The frame is the main and most important component of a bike as all other components are attached to it. The vast majority of frames follow the standard diamond frame design comprising:

Head tube

This is at the front end of the frame and houses the headset, which contains the bearings for the fork.

Top tube (cross-bar)

Traditionally, the top tube is horizontal and parallel to the ground. In a compact-geometry frame and mountain bike frames, however, the top tube is sloped downward towards the seat tube for greater comfort. Step-through frames have a top tube that slopes steeply allowing the rider to mount and dismount the bike more easily.

Down tube

This connects the head tube to the bottom bracket shell.

Seat tube

This contains the seatpost and saddle whose height can be adjusted by altering how far the seatpost is inserted down into the seat tube.

Chain stays

These connect the bottom bracket shell to the rear fork ends and run parallel to the chain.

Seat stays

These connect the seat tube to the rear fork dropouts. A dual seat stay meets the seat tube at two separate points, side by side, whereas a wishbone or single seat stay joins the stays together into a monotube which in turn attaches to the seat tube.

Bottom bracket shell

This holds the bottom bracket and connects the chain stays, seat tube and down tube.

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