Banana seat

A bicycle saddle, often called a seat, is one of three contact points on an upright bicycle, the others being the pedals and the handlebars. (A bicycle seat in the specific sense also supports the back.) The bicycle saddle has been known as such since the bicycle evolved from the draisine, a forerunner of the bicycle. It performs a similar role as a horse's saddle, not bearing all the weight of the rider as the other contact points also take some of the load.

A bicycle saddle is commonly attached to the seatpost and the height of the saddle can usually be adjusted by the seatpost telescoping in and out of the seat tube.

Typical saddles are composed of a few identifiable components.

The shell creates the shape of the saddle. The nose of the saddle is the forward most part. It is usually rounded. The shell can be made from several materials.

Most modern saddles have a hard shell made from a moulded piece of plastic, such as nylon. Carbon fiber may also be used.

Leather saddles do not have a hard shell. Instead a moulded piece of thick leather is stretched, like a taut hammock, between the front and rear ends of the rails. Traditional leather saddles such as those made by Brooks have been used for many years. Such a saddle is generally more comfortable after a break-in period during which it conforms to the shape of the rider, so long as the basic shape is right to start with.

Most saddles use some form of padding on top of the hard shell (often closed cell foam, gel, or gel-foam) followed by an outer cover consisting of spandex, vinyl, artificial leather, or leather.

Saddles designed for hard use e.g. mountain bike or BMX style riding, may have additional cover reinforcements such as kevlar sewn to the cover to withstand abrasion on those areas most prone to abrasion.

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Wikipedia