Hybrid bicycles blend characteristics from more specialized road bikes, touring bikes and mountain bikes. The resulting "hybrid" is a general-purpose bike that can tolerate a wide range of riding conditions and applications. Their stability, comfort and ease of use make them popular with novice cyclists, casual riders, commuters, and children.
Hybrids typically borrow the flat, straight handlebars and upright seating posture of a mountain bike, which many bicyclists find comfortable and intuitive. Hybrids also employ the lighter weight, thinner wheels and smooth tires of road bikes, allowing for greater speed and less exertion when riding on the road. Hybrid bikes often have places to mount racks and bags for transporting belongings, much like a touring bike.
Hybrid bikes have spawned numerous sub-categories satisfying diverse ridership. They are classified by their design priorities, such as those optimized for comfort or fitness — and those offered as city, cross or commuter bikes.
History
From the early 20th century until after World War II, the utility roadster constituted most adult bicycles sold in the United Kingdom and in many parts of the British Empire. In Britain, the roadster declined noticeably in popularity during the early 1970s, as a boom in recreational cycling caused manufacturers to concentrate on lightweight , affordable derailleur sport bikes, actually slightly-modified versions of the racing bicycle of the era. In the 1980s, U.K. cyclists began to shift from road-only bicycles to all-terrain models such as the mountain bike. The mountain bike's sturdy frame and load-carrying ability gave it additional versatility as a utility bike, usurping the role previously filled by the roadster. By 1990, the roadster was almost dead; while annual U.K. bicycle sales reached an all-time record of 2.8 million, almost all of them were mountain and road/sport models. A different situation, however, was occurring in most Asian countries: roadsters are still widely made and used in countries such as China, India, Thailand, Vietnam and others as well in parts of north-western Europe.
Trekking bike
thumb|Lightweight trekking bike
A trekking bike is a hybrid with all the accessories necessary for bicycle touringmudguards, pannier rack, lights etc.
Cross bike
Cross bikes use a road bicycle frame similar to a racing or sport/touring bicycle, and are normally equipped with nearly flat handlebars to provide a more upright riding position than a racing or sport/touring bike. They usually feature a longer wheelbase, mountain bike-sized 26-inch (ISO 559) wheels or 700c wheels, a more upright riding position, and tyres approximately wide. These wider tyres allow the use of lower tyre pressure compared with narrower road tyres, which can improve comfort on uneven surfaces and increase grip on unsealed surfaces such as gravel trails. Using a sturdy welded chromoly or aluminium frame derived from mountain bike designs, the city bike is designed to withstand impacts from urban conditions such as potholes and city curb drops.