Chainline is the angle of a

bicycle chain A bicycle chain is a roller chain that transfers power from the pedals to the drive-wheel of a bicycle, thus propelling it. Most bicycle chains are made from plain carbon or alloy steel, but some are nickel-plated to prevent rust, or simply ...

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 triangl ...

. A

bicycle A bicycle, also called a pedal cycle, bike or cycle, is a human-powered or motor-powered assisted, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A is called a cyclist, or bicyclist. Bic ...

is said to have 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 with teeth that mesh with a chain, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which radial projections engage a chain passi ...

is directly behind the front

chainring The crankset (in the US) or chainset (in the UK), is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain or belt, which in turn drives the rear whee ...

. Chainline also refers 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