British Masters Cycle Racing promote racing for riders aged 40 or over, based upon age groups. In a BMCR race, you’ll be racing against riders of a similar age.
This provides some levelling of the playing field, but cycling is one of those sports in which increasing age has relatively little impact on performance; so as a newcomer you might find yourself up against ex regional or national champions who just happen to be a similar age to you. Races are normally open to two or three five-year age groups, so an event may include a 40-49’s race, a 50-59’s race, and an over 60’s race. Within each one, places and prizes will be awarded to the top finishers in each five-year age band.