[[File:Chainline (3621138368).jpg|thumbnail|Chainline on a fixed-gear bicycle]] The '''chainline''' is the angle of a bicycle chain relative to the centerline of the bicycle frame.<ref name = Brown>{{cite web | url = http://sheldonbrown.com/chainline.html | title = About Bicycle Chainline | author = Sheldon Brown, John Allen | authorlink = Sheldon Brown (bicycle mechanic) | date = 2012 | accessdate = 2013-03-16}}</ref> A bicycle is said to have a perfect chainline if the chain is parallel to the centerline of the frame, which means that the rear sprocket is directly behind the front chainring.<ref name = Brown/> 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.<ref name = Brown/> This is the main reason that a single-speed bicycle can be more efficient than a derailleur geared bicycle. Single-speed bicycles should have the straightest possible chainline.<ref>{{cite web | url = http://sheldonbrown.com/fixed-conversion.html | title = Fixed Gear Conversions | author = Sheldon Brown | authorlink = Sheldon Brown (bicycle mechanic) | date = 2011-11-22 | quote = with a fixed-gear setup. It is quite important to get the chain line just right. | accessdate = 2013-03-16}}</ref>
==See also== * Bicycle gearing * Bicycle performance
==References== {{reflist}}
Category:Bicycle drivetrains