The seatpost (silver) connects the saddle to the frame (red)

A bicycle seatpost or seatpin is an adjustable tube that extends upwards from the bicycle frame to the saddle. It is made of steel, aluminum, titanium, or carbon fiber. The size of the seatpost is dependent upon the internal dimensions of the seat tube of the bicycle frame. They come in various diameters, lengths and offsets. Offset is the distance between the centerline of the seatpost tube, and the centerline of the clamp area. Image File history File links Sattelkerze. ... Image File history File links Sattelkerze. ... Steel frame and carbon fiber fork of 2000 Lemond Zurich racing bicycle A bicycle frame is the main component of a bicycle, onto which wheels and other components are fitted. ... Steel frame and carbon fiber fork of 2000 Lemond Zurich racing bicycle A bicycle frame is the main component of a bicycle, onto which wheels and other components are fitted. ... A bicycle saddle is one of three contact points on a typical upright bicycle, the others being being the pedals and the handlebars. ... The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ... Aluminum is a soft and lightweight metal with a dull silvery appearance, due to a thin layer of oxidation that forms quickly when it is exposed to air. ... General Name, Symbol, Number titanium, Ti, 22 Chemical series transition metals Group, Period, Block 4, 4, d Appearance silvery metallic Atomic mass 47. ... Graphite-reinforced plastic or carbon fiber reinforced plastic (CFRP or CRP), is a strong, light and very expensive composite material or fibre reinforced plastic. ...

Seatpost generally clamp onto saddle rails.

Types

Time trial

Some modern time trial bicycles are made from one piece of molded carbon fiber with an integrated seatpost that is cut to length depending upon the rider. The advantage is that it is lighter, can be molded into an aerodynamic shape, and removes the need to clamp an irregular tube shape. The disadvantage of this setup is that the seatpost height is not as adjustable. There is usually 2-3 centimeters of adjustment with the clamping device.

Suspension

Suspension seatposts incorporate a spring or elastomer and possibly a damping mechanism to insulate against bumps. These seatposts are most common on hybrid and mountain bikes. It has been suggested that Coil spring be merged into this article or section. ... The term elastomer is often used interchangeably with the term rubber, and is preferred when referring to vulcanisates. ... Damping is any effect, either deliberately engendered or inherent to a system, that tends to reduce the amplitude of oscillations of an oscillatory system. ... A hybrid bicycle is a compromise between a road bicycle and a mountain bicycle. ... A cross country mountain bike race A hardtail mountain bike A mountain bike, mountain bicycle or ATB (All Terrain Bicycle) is a bicycle designed for mountain biking, either on dirt trails or other unpaved environments. ...

External links

• Sheldon Brown's seatpost sizing database