The hour record for bicycles is the record for the longest distance cycled in one hour on a bicycle. There are several records. The most famous is for upright bicycles meeting the requirements of the Union Cycliste Internationale (UCI). It is one of the most prestigious in cycling. Hour-record attempts are made in a velodrome, frequently at high altitude for the aerodynamic benefit of thinner air.
The first recorded record was in 1876 when the American Frank Dodds rode 26.508 km (16.471 mi) on a penny-farthing. In 1972, Eddy Merckx set a record of 49.431 km (30.715 mi) that stood for 12 years. The current UCI record is by Ondřej Sosenka, 49.700 km (30.882 mi), the current WHPVA/IHPVA record by Francesco Russo stands at 91.56 km (56.89 mi).
Because of aerodynamics, the hour record has seen innovative equipment, but this has led to debate in cycling over the extent to which records should reflect only the skill, strength and stamina of the cyclist on an upright bike with drop handlebars, or whether changes in bicycle design should be accepted.