do not get caught up in the bike chain or other parts of the bike;
reduce the weight of a rider's clothing ; and
improve comfort during long rides with extra padding in the seat area.
Historically, cycling shorts were made of knit black wool, which hides wear marks caused by sitting on an oiled leather saddle for extended periods of time, with a chamois leather padding inside the shorts in the crotch area, which reduces chafing from the bicycle saddle. Modern cycling shorts are often made of spandex with a synthetic chamois which acts as an elastic interface between the cyclist's body and the saddle, and are produced in a variety of shapes and styles to suit the needs of different riders. On some cycling shorts different materials are often placed on different parts of the shorts to take advantage of each material's benefit, providing a very efficient cycling short. For example, the patterns used for the chamois on women's cycling shorts tend to be quite different from those used for men's. The hem of each leg is usually lined with elastic and/or silicone that clings to the skin, keeping it in a fixed position. These shorts made from several panels fit better and are more beneficial, especially for racers, but cost more. Short-legged elastic tights commonly worn as street wear, under girls' skirts and dresses, for gymnastics and ballet practice, or under athletic and running shorts, are sometimes also referred to as "bike shorts", but they are typically simpler and lighter garments than those worn by cyclists and generally lack the chamois or faux-chamois lining.
Bib shorts
Bib shorts are cycling shorts that are held up by a bib instead of an elastic waistband. Pro and serious riders tend to prefer bib shorts over non-bib shorts due, to the discomfort that often occurs with an elastic waistband, such as tightness and chafing. The bib part of the short is often made of spandex and polyester with large sections of netting to help keep the rider cool. The idea of modern bib shorts was a development from the braces or suspenders that cyclists once used to hold up old-fashioned wool shorts, which had a tendency to become loose and heavy from riders' sweat. Bib shorts are well-suited to tall riders and riders with protruding stomachs because regular shorts can tend to fall down in the back while riding.
These shorts typically are more loose than bib shorts but still not baggy. This is because they are focused more on protecting the rider during falls and are not as focused on aerodynamic efficiency. The position of the padding is a little different because mountain bikers have a more upright stance when riding. These shorts are different from baggy shorts as they are used by hardcore cyclists who still need the protection with a good padding, which the baggy shorts do not have.
Baggy shorts
Baggy shorts are cycling shorts that look like regular shorts on the outside, but that are designed for cycling. Some have a thin chamois lining on the inside. This lining ranges from polyester fabric to full eight-panel, form-fitting cycling shorts beneath the baggier outside shorts. Others are designed to be worn with a separate liner short underneath. These shorts provide a more casual look when riding around town and off dedicatedbike paths. These shorts are basically dual purpose in that the wearer need not to change from tight singular purpose cycling shorts into casual clothes when going out yet have some of the benefits of wearing cycling shorts.
