Bicycle gear refers to the system of components that help cyclists adjust their pedaling effort and speed. It typically includes a set of gears on the bike's front chainring and rear cassette, allowing riders to shift between different gear ratios. This adjustment helps optimize performance on various terrains, making it easier to climb hills or accelerate on flat surfaces. The gear mechanism is controlled by shifters located on the handlebars, which connect to derailleurs that move the chain between gears. Proper use of bicycle gear can enhance efficiency and comfort during rides, contributing to a more enjoyable cycling experience.