Bicycle gearing

Bicycle gearing is the arrangement of chainrings, sprockets, and ratios that sets wheel travel and mechanical advantage for each pedal revolution.

Gear ratio: The ratio between the rotational speeds or tooth counts of connected gears. A bicycle’s selected chainring and sprocket create the ratio that sets wheel turns per crank turn.
Bicycle crankset: The assembly of crank arms and one or more chainrings that transfers pedaling force to the drivetrain. Its chainrings provide the front tooth counts used to calculate bicycle gear ratios.
Bicycle climbing: The technique and physical demands of riding a bicycle uphill. Low gears let riders maintain cadence while producing less force at the pedals.
Derailleur gears: A bicycle gear system that shifts the chain among different chainrings or rear sprockets using derailleurs. This common system changes ratios by moving the chain between exposed sprockets.
Mountain bike gearing: Gear configurations designed for mountain bicycles and steep, variable off-road terrain. Its very low ratios address slow, steep climbs and technical riding.
Gear inches: A bicycle gearing measure equal to wheel diameter multiplied by the front-to-rear tooth-count ratio. It expresses a gear ratio as the effective wheel size for comparing combinations.
Chainring: A toothed ring attached to a bicycle crank that drives the chain. Changing chainring size changes the front half of the drivetrain ratio.
Bicycle cadence strategy: The practice of choosing a pedaling rate suited to terrain, effort, and rider physiology. Riders shift gears to keep cadence within a comfortable or efficient range.
Hub gear: A bicycle transmission with selectable ratios enclosed inside the rear hub. It contrasts with derailleur gearing in where ratios are produced and how exposed the mechanism is.
Road bicycle gearing: Gear configurations designed for road bicycles and paved-road riding. Road setups balance climbing range with closely spaced ratios for steady speed.

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