The chainline is the angle of a

bicycle chain A bicycle chain is a roller chain that transfers power (physics), power from the Bicycle pedal, pedals to the Drive wheel, drive-Bicycle wheel, wheel of a bicycle, thus propelling it. Most bicycle chains are made from carbon steel, plain carbo ...

relative to the centerline of the

bicycle frame A bicycle frame is the main component of a bicycle, onto which wheels and other components are fitted. The modern and most common frame design for an upright bicycle is based on the safety bicycle, and consists of two triangles: a main triangle ...

. A

bicycle A bicycle, also called a pedal cycle, bike, push-bike or cycle, is a human-powered transport, human-powered or motorized bicycle, motor-assisted, bicycle pedal, pedal-driven, single-track vehicle, with two bicycle wheel, wheels attached to a ...

is said to have a perfect chainline if the chain is parallel to the centerline of the frame, which means that the rear

sprocket A sprocket, sprocket-wheel or chainwheel is a profiled wheel A wheel is a rotating component (typically circular in shape) that is intended to turn on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the whe ...

is directly behind the front

chainring The crankset (in the US) or chainset (in the UK) is the component of a Bicycle drivetrain systems, bicycle drivetrain that converts the reciprocating motion of the rider's human leg, legs into rotational motion used to drive the bicycle chain, ...

. Chainline can also refer to the distance between a sprocket and the centerline of the frame. Bicycles without a straight chainline are slightly less efficient due to frictional losses incurred by running the chain at an angle between the front chainring and rear sprocket. This is the main reason that a

single-speed bicycle A single-speed bicycle is a type of bicycle with a single gear ratio. These bicycles are without derailleur gears, hub gearing or other methods for varying the gear ratio of the bicycle. There are many types of modern single speed bicycles; BMX b ...

can be more efficient than a derailleur geared bicycle. Single-speed bicycles should have the straightest possible chainline.

References

{{reflist Bicycle drivetrains

See also

References