Gravel bicycle
A gravel bicycle is a type of bicycle intended for gravel cycling, including gravel racing. They are also sometimes known as "adventure bicycles", particularly ones intended for harsher off-road terrain. While bicycles have been used for riding on such roads since bicycles were invented, the "modern" gravel bicycle, as a category, evolved in the 2000s, adopting technology from road bicycles, cyclocross bicycles and mountain bikes. They also share many characteristics of touring bicycles, such as relaxed geometry, wide tires and wide-range gearing. Design characteristics Gravel bikes have been constructed out of a wide variety of frame materials, including aluminium, carbon fibre, titanium and steel. The vast majority of gravel bikes include rigid front forks, being carbon fibre and chromoly forks the most used given its inherent vibration-absorbing properties. Gravel bicycles generally use drop bars, similar to racing and cyclocross bicycles, unlike mountain bikes and hybrid bicycles. Many gravel bikes are fitted with wider bars than would be typical for a road or cyclocross bike, and a few have been fitted with "flared" bars that angle outwards. Clip-on aerobar extensions are sometimes used, particularly in racing. Gravel bikes have frame geometry that is intermediate between a road bike and a cross-country