Types of road bike
The most common is the standard configuration on which the rider sits upright, leaning forward to hold the handlebars and pedaling with his feet below the torso. This configuration is used for cruising, racing and touring. Recumbent bicycles, in contrast, allow the rider to lean backward and recline while pedaling with her feet in front of her torso.
Most road bikes have pedals and cranks attached to a chain that transfers foot power to the propelling wheel, usually the rear one. Old-fashioned bikes, sometimes called velocipedes, have pedals attached directly to the front wheel. Most road bikes have handlebars that attach via forks to the front wheel to allow steering. Tandem and other bikes have two or more seats, handlebars, pedals and cranks to permit multiple riders to propel them.
The basis for a road bike is the frame, generally a rigid double triangle of metal tubes, at the corners of which are attached the seat, pedals and crank, rear wheel, handlebars and front steering fork and wheel.
In front of and behind the frame are two wheels, usually composed of rubber tires, inflatable inner tubes with inflation stems, valves and valve caps, metal wheel frames, wire spokes attaching the wheel frames to the metal hubs, inside which are ball bearings to reduce friction while turning.
The frame generally attaches to the rear wheel whereas the handlebars and front fork, a U-shaped metal frame that wraps around the wheel, attach to the front wheel, permitting the rider to steer the bike. A variation on the standard frame is the step-through, which lacks a horizontal top piece between the seat post and handlebar post.
Cruising bikes usually have one gear and brakes that are operated by pushing the pedals backward to activate a "coaster" brake attached to the hub of the rear wheel. Touring bikes often have three or more gears, permitting operation at different pedaling ratios, via either a mechanism contained within the hub of the rear wheel or exterior sprockets on the rear wheel and sometimes different-sized sprockets on the crank attached to the pedals. Racing bicycles usually have 18 or more gears, using several front and rear sprockets and devices for moving the propelling chain horizontally between called derailleurs that are operated by controllers mounted on the handlebars and connected by metal cables.
Seats have a variety of configurations but generally are saddle-shaped. They are often made of metal and covered in leather or plastic with some degree of padding. Some have springs or other shock absorbers.
Handlebars are usually metal tubes mounted diagonally to the frame, with tape, foam or rubber handle grips and upon which are typically attached brake handles and gear shifters. Their configurations can vary, but typical types are the standard, with slightly upswept ends, and racing, with U-shaped and downswept ends.
Foot pedals are usually either metal or metal and rubber pegs. The rider's foot rests on the pedal to propel the bike via the crank, upon which the pedals swivel. The crank attaches to the frame via a hub within which are ball bearings.
Non-coaster brakes usually have levers attached to the handlebars and are connected by metal cables to a pinching apparatus straddling the front and back wheels. These brakes use the friction of rubber pads against the metal wheel frames to slow or stop the bike.
Road bikes can have fenders attached to the wheels for preventing road water from spraying the rider, cargo platforms and/or baskets attached above the rear wheel or the handlebars for carrying loads, reflectors and lights for visibility in dim lighting or at night, noise makers such as bells or horns for alerting others to the bicycle's proximity and a variety of locks for attaching the bike to a fixed object to prevent theft.