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Bicycle frame

A bicycle frame is the main component ofand standing on the ground is called
a bicycle, onto which wheels and otherclearance. The total height from the
components are fitted. The modern andground to this point is called the
most common frame design for an uprightstandover height.
bicycle is based on the safety bicycle,Down tube
and is made of two triangles, a mainThe down tube connects the head tube to
triangle and a paired rear triangle.the bottom bracket shell. On racing
This is known as the diamond frame. Thebicycles and some mountain and hybrid
main triangle consists of the head tube,bikes, the derailleur cables run along
top tube, down tube and seat tube. Thethe down tube. On older racing bicycles,
rear triangle consists of the seat tube,the gear levers were mounted on the down
and paired chain stays and seat stays.tube. On newer ones, they are integrated
The head tube contains the headset, thewith the brake levers on the handlebars.
interface with the fork. The top tubeBottle cage mounts are also on the down
connects the head tube to the seat tubetube. In addition to bottle cages, small
at the top, and the down tube connectsair pumps may be fitted to these mounts
the head tube to the bottom bracketas well.
shell. The rear triangle connects to theSeat tube
rear dropouts, where the rear wheel isThe seat tube contains the seatpost of
attached. It consists of the seat tubethe bike, which connects to the saddle.
and paired chain stays and seat stays.The saddle height is adjustable by
The chain stays run parallel to thechanging how far the seatpost is
chain, connecting the bottom bracket toinserted into the seat tube. On some
the rear dropouts. The seat staysbikes, this is achieved using a quick
connect the top of the seat tube (oftenrelease lever. The seatpost must be
at or near the same point as the topinserted at least a certain length; this
tube) to the rear dropouts.is marked with a minimum insertion mark.
Unless otherwise specified, theThe seat tube also may carry bottle cage
remainder of this article focusesmounts.
primarily on the diamond frame.Chain stays
The diamond frame consists of twoThe chain stays run parallel to the
triangles, a main triangle and a pairedchain, connecting the bottom bracket
rear triangle. The main triangleshell to the rear dropouts. When the
consists of the head tube, top tube,rear derailleur cable is routed
down tube and seat tube. The rearpartially along the down tube, it is
triangle consists of the seat tube, andalso routed along the chain stay. The
paired chain stays and seat stays.chain stays provide a mount for rear
Head tubedisc brakes.
The head tube contains the headset, theSeat stays
interface with the fork. In anThe seat stays connect the top of the
integrated threadless headset, theseat tube (often at or near the same
bearings interface directly with thepoint as the top tube) to the rear
metal surface on the inside of the headdropouts. When the rear derailleur cable
tube.is routed partially along the top tube,
Top tubeit is also routed along the seat stay.
The top tube connects the head tube toOne combination aluminum/carbon fiber
the seat tube at the top. In a mountainracing frame design uses carbon fiber
bike frame, the top tube is almostfor the seat stays and aluminum for all
always sloped. In a traditional-geometryother tubes. This takes advantage of the
racing bicycle frame, the top tube isbetter vibration absorption of carbon
horizontal. In a compact-geometry frame,fiber compared to aluminum.
the top tube is sloped. See Road andA single seat stay refers to seat stays
triathlon bicycles for more informationwhich merge onto one section before
on geometries.joining the front triangle of the
Control cables are routed along mountsbicycle, thus meeting at a single point.
on the top tube. Most commonly, thisA dual seat stay refers to seat stays
includes the cable for the rear brake,which meet the front triangle of the
but some mountain bikes and hybridbicycle at two separate points, usually
bicycle also route the front and rearside-by-side. The seat stays also
derailleur cables along the top tube.provide a mounting point for the rear
The space between the top tube and therim brakes.
rider's groin while straddling the bike



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