Understanding Bike Gears

Gear systems have gotten complicated with all the drivetrain options, electronic shifting technologies, and gear ratio debates flying around. As someone who’s helped countless new cyclists understand their bikes—and fine-tuned plenty of derailleurs myself—I learned everything there is to know about how gears work and how to use them effectively.

The Basics of Bike Gears

Bikes commonly have multiple gears managed by shifters on the handlebars. Each gear combination offers different resistance levels. Lower gears make pedaling easier; higher gears increase resistance.

How Gears Work

Gears consist of chainrings and cogs. Chainrings are attached to the pedals; cogs are part of the rear wheel. The chain moves between these to change gears.

Cassette and Freewheel

Probably should have led with this section, honestly. The cluster of cogs on the rear wheel is known as a cassette or freewheel. Modern bikes typically use cassettes. Freewheels are found on older or entry-level bikes. Both serve the same purpose but have different mechanisms.

Derailleurs

Derailleurs move the chain between gears. The front derailleur shifts the chain between chainrings. The rear derailleur manages the gears on the cassette. These components work together to change resistance.

Types of Bike Gears

Single-Speed

Single-speed bikes have one gear ratio. Simple and require little maintenance. Ideal for flat terrain and short distances.

Fixed-Gear

Fixed-gear bikes have a single gear with the cog directly attached to the wheel. Pedaling controls both speed and braking. Requires more skill but provides a different riding experience.

Multi-Speed

Multi-speed bikes offer a range of gears with multiple chainrings and cassettes. Ideal for varied terrain. Found on road, mountain, and hybrid bikes.

Shifting Gears

Anticipate Terrain

Shift gears before reaching a hill. This prevents strain on the chain and keeps momentum steady.

Pedal Smoothly

Avoid sudden power bursts while shifting. Maintain steady pressure on the pedals to protect gears from wear.

Use Wide Gear Range

Avoid cross-chaining—when the chain is at an extreme angle. Use gear combinations that keep the chain straight for smoother riding and longer gear life.

Choosing the Right Gear

Flat Terrain: Use middle gears for balanced resistance and speed.

Uphill: Shift to lower gears before climbing to make pedaling less strenuous. Maintain steady cadence to conserve energy.

Downhill: Use higher gears for more resistance and control. Avoid spinning out by adjusting gradually.

Components of Bike Gearing Systems

• Chainrings: Attached to the pedals, come in different sizes.
• Crankset: Includes chainrings and crank arms connecting pedals to the bike.
• Cassette: Cluster of cogs on the rear wheel.
• Derailleurs: Mechanisms that move the chain between gears.
• Shifters: Controls on handlebars used to change gears.
• Chain: Connects chainrings and cassettes.

Maintaining Bike Gears

That’s what makes gear maintenance endearing to us mechanical-minded cyclists—a well-tuned drivetrain is a joy to ride. Clean the gears and chain regularly. Lubricate with proper bike lubricant—not household oil. Inspect gears for wear and tear and replace faulty parts as needed.

Advancements in Bike Gearing

Electronic Shifting: Provides precise shifts using battery-powered mechanisms. Popular in high-end bikes.

Internal Gear Hubs: House gears inside the rear wheel for smooth shifting and low maintenance. Common in commuter and touring bikes.