A folding bicycle is a type of bicycle that incorporates hinges or joints in the frame that permit it to be broken down into a more compact size. Most 'folders' have 20 inch (51 cm) diameter wheels, or less. Folding bikes can be taken on public transport and into apartment buildings or workplaces where conventional bicycles are not allowed. This facilitates mixed-mode commuting, because a folding bike can be carried on any available transport, and ridden when there is none. Folding bikes are also easier to transport in a car.
Most folding bicycles are intended for commuter and utility purposes, hence emphasize ruggedness, comfort and convenience over speed. A small number of high-end folding bikes are made for speed. In the interest of compact folding, certain trade-offs are common. Most folding bicycles use small (20 inches (51 cm) or less) diameter wheels. All else being equal, smaller diameter wheels give a rougher ride than larger wheels. Folding bicycles often have a shorter wheelbase, which also contributes to a rougher ride. To avoid losing any more comfort, narrow tires are rarer than for non folders. Suspension systems can be incorporated into the design of a bicycle to give a smoother ride. The suspension, however, will also absorb some of the pedaling energy that would otherwise be used to move the bicycle forward in a more rigid bicycle.[citation needed]
