Bicycle Gearing: Understanding Speeds, Cadence, and Performance

What are the speeds for on a bike?

The "speeds" on a bike refer primarily to its gearing system, which allows a rider to adjust the mechanical advantage, or resistance, of their pedaling effort to suit varying terrains, energy levels, and performance goals, thereby optimizing both cadence and ground speed.

Understanding "Speeds" on a Bicycle

When we talk about "speeds" on a bicycle, we are not just referring to how fast the bike is moving over the ground. More accurately, we are discussing the bike's gearing system, which allows you to change the resistance felt at the pedals. This system enables you to maintain an efficient pedaling rhythm, or cadence, regardless of whether you're climbing a steep hill, cruising on a flat road, or sprinting for the finish line. Each "speed" or gear combination offers a different gear ratio, dictating how many times the rear wheel turns for each full revolution of the pedals.

The Mechanics of Bicycle Gearing

Modern bicycles typically employ a derailleur system, which moves the chain between different-sized cogs and chainrings to alter the gear ratio.

• Front Chainrings: Located at the pedals, these typically range from one (on single-speed or some gravel/mountain bikes) to three (on older road bikes or touring bikes). A larger chainring provides a "harder" gear, requiring more effort per pedal stroke but potentially yielding higher speeds.
• Rear Cogs (Cassette): Located on the rear wheel, these are a set of multiple cogs of varying sizes. A smaller rear cog provides a "harder" gear, while a larger rear cog provides an "easier" gear.
• Gear Ratio: The combination of the chosen front chainring and rear cog determines the gear ratio. A large front chainring paired with a small rear cog results in a high gear (harder to pedal, more distance per pedal stroke). A small front chainring paired with a large rear cog results in a low gear (easier to pedal, less distance per pedal stroke).

Low Gears: When and Why to Use Them

Low gears are characterized by an easier pedal stroke, allowing for a higher cadence at a slower ground speed. They are essential for:

• Climbing Steep Grades: Low gears significantly reduce the effort required to pedal uphill, allowing you to maintain momentum and conserve energy without grinding to a halt. This is crucial for sustained ascents.
• Starting and Accelerating: Beginning from a standstill or accelerating slowly is much easier in a low gear, reducing stress on your knees and the drivetrain.
• Low-Impact Training and Recovery: For recovery rides or individuals seeking a lower-impact workout, low gears allow for higher cadences with less muscular strain, promoting blood flow without excessive fatigue.
• Technical Riding: Navigating tricky terrain, tight turns, or obstacles often requires precise control at slower speeds, which low gears facilitate.

High Gears: When and Why to Use Them

High gears provide more resistance per pedal stroke, meaning each revolution covers more ground distance. They are used for:

• Descending and Flat-Out Speed: On downhill sections or flat roads, high gears allow you to pedal effectively at high speeds without spinning your legs uncontrollably (spinning out).
• Building Strength and Power: Pushing a harder gear requires greater muscular force, which can help develop leg strength, power, and anaerobic capacity, especially when combined with lower cadences in structured training.
• Maintaining Momentum: When you need to keep speed on rolling terrain or through a strong headwind, a higher gear can help maintain momentum more efficiently than constantly shifting or spinning.

The Crucial Role of Cadence

Cadence, measured in revolutions per minute (RPM) of your pedals, is arguably more important than ground speed for efficient and sustainable cycling.

• Defining Cadence: It's how fast you're pedaling, irrespective of the gear or the bike's speed.
• Efficiency and Performance: Most cyclists find an "optimal" cadence range (often between 80-100 RPM for road cyclists) where they can produce power most efficiently, minimizing fatigue and maximizing endurance. A higher cadence in a lower gear often feels smoother and is less taxing on the muscles and joints than grinding a very hard gear at a low cadence.
• Injury Prevention: Maintaining a higher cadence reduces the stress on your knees and other joints, as the force is distributed over more revolutions rather than concentrated in fewer, more powerful strokes.

Matching Gears to Training Goals

Understanding the purpose of different "speeds" allows cyclists to tailor their rides to specific training objectives:

• Endurance Riding: Focus on maintaining a consistent, comfortable cadence (e.g., 85-95 RPM) using gears that allow for sustained effort without excessive muscular fatigue.
• Strength and Power Development: Incorporate periods of lower cadence (e.g., 50-70 RPM) in harder gears on gradual inclines or flats. This "grinding" builds muscular strength.
• Speed and Sprinting: Utilize higher gears to maximize ground speed during sprints or high-intensity intervals, pushing the limits of your power output.
• Recovery Rides: Employ very easy gears and higher cadences to promote blood flow and flush out metabolic byproducts without adding significant stress.

Mastering Gear Selection: Practical Tips

Effective gear shifting is an art that enhances efficiency, comfort, and performance.

• Anticipate the Terrain: Look ahead for hills, descents, or changes in wind direction. Shift before you need the gear, not while you're struggling. For example, shift to an easier gear before starting a climb.
• Listen to Your Body: Your legs and breathing will tell you if you're in the right gear. If you're straining, shift to an easier gear. If your legs are spinning wildly with little resistance, shift to a harder gear.
• Smooth Shifting: Ease off the pedal pressure slightly when shifting, especially with the front derailleur, to ensure a smooth transition and prevent chain jams.
• Experiment and Learn: Practice shifting and pay attention to how different gear combinations feel on various terrains. Over time, gear selection will become intuitive.

Conclusion

The "speeds" on a bike are not merely about how fast you go, but about intelligently managing your effort through the bike's gearing system. By understanding the purpose of low and high gears, and the critical role of cadence, cyclists can optimize their performance, enhance their training, and enjoy a more efficient and comfortable riding experience across any terrain. Mastering your bike's gears is fundamental to becoming a more capable and confident cyclist.