A track bicycle or track bike is a bicycle designed for racing at a velodrome. Unlike road bicycles, they have a single gear, no freewheel, and no brakes. Tires are narrow and at high pressure to reduce rolling resistance. Tubular tires are often used.
A track frame
is specific to its use. Rigidity is more important than lightness. Frames for sprinting are as rigid as possible, while those for general racing as aerodynamic as possible.
The governing body, the International Cycling Union
(UCI), sets limits on design and dimensions as well as the shape and diameter of the tubes used to construct the frame.
A track bicycle differs from one used on the road by having:
Typical track frames use 120mm spacing for the rear hub. The dropouts or track ends face backwards to facilitate chain tension adjustment.
Frames can be made of steel
, carbon fiber
, or titanium
. Carbon fiber is most common at the professional level.
Track bicycles have only one gear so its size is important. A lower gear allows quicker acceleration or 'jump.' But a bigger gear makes sustain speed easier, important in pursuit
, time trial
and bunched races such as points or scratch events.
Without a good jump, the rider risks opponents accelerating away; without good sustained speed, he will be unable to keep up with a fast race. Track cyclists practise fast pedalling as a compromise.
Long-distance attempts such as the hour record use high gear combinations such as 52x12 or 55x14. Ondřej Sosenka used 54x13 with 190mm cranks to set the 2005 record.
There are two common widths of single speed and fixed gear bicycle chains
: 1/8 inch and 3/32 inch. The chainring, sprocket and chain should all be the same width. Although an 1/8-inch chain will work on a 3/32-inch chainring or sprocket, it is not ideal. A 3/32-inch chain will not work on a 1/8-inch chainring or sprocket. Because they do not need to shift from sprocket to sprocket, track chains use a full bushing to allow little flex and to be stronger. All bicycles with derailleur
gears use bushingless chains which flex, making gear changing possible.