Although all bicycles are made up of the same basic componts, they can vary greatly in design . A racing bike , such as the Eddy Merckx  model , with its light frame and steep head – seat head – and seat angles – , is built for speed . its design forces the rider to adopt the ”aerotuck” a crouched , aerodynamic position . While a touring bike resemble the racing bike in many respects , it is designed for comfort and stability on long – distance journeys . Touring bikes are characterized by more relaxed frame angles , heavy chain stays that support the rear panniers , and a long wheel base  9 the distance between the wheel axle 0 for reliable handling . All-around bicycles known as ” hybrids ”, combine the light weight and speed of sports bikes with the rugged durability of mountain bikes. Bicycles that are not designed for conventional road use include time trial bikes , which have a short head tube , sloping top tube  , ” aero ” handlebars , and aerodynamic tubing . Most human powered vehicles  ( HPVs ) are regiments – which maximize power output and minimize drag ( resistance ) . Essential to the safety of all riders are helmets , and both front and rear lights ; locks protect against theft .