A 2000 Klein Quantum, illustrating the typical road bike.
A road bicycle is a type of bicycle with narrow tyres. They usually come equipped with drop bars, which curve down and backwards, allowing for a variety of hand positions.
Road bikes may be constructed from many materials, although steel, aluminium, and carbon fibre are the most common.
Road bikes are used in most road races (with the exception of some time trials).
Road bike frame sizes are measured in centimeters, based on the seat tube. Sizes range from XXS (47cm) to XXL (60-64cm) which are enough to suit most riders between 4' 10" and 6' 5". Larger frames will generally have steeper head tubes and slacker seat tubes, and offer a slightly more upright riding position.