A reliability trial is an organised bicycle ride which challenges a cyclist to complete a course, passing through designated control points, within a preset time limit.
In the United Kingdom, such events are often held in the wintry opening months of the year and are used by club cyclists as training rides.
The term is historic and dates back to the early years of the 20th century when cycling equipment was less reliable, roads were rougher, routes were more poorly sign-posted, and mobile telephones had yet to be invented.
The name was also a way of emphasising to the police, at a time when the place of cycle sport on British roads was insecure, that the mass rides they might see were not races.
Reliability trial riders needed to be self-sufficient, adept at navigation, able to deal with mechanical problems, and fit enough to complete the course.