Bicycle Gears: Understanding Their Function and Setup

Overview

• Gears are essential for bicycles, enabling riders to tackle steep climbs and maintain momentum on flat terrain.
• Bicycle gears consist of three main components:
  • Chain rings and front derailleur
  • Cassette, rear derailleur, and pulley wheels
  • Shifters

Chain Rings

• Located on the cranks, typically two chain rings are found on road bikes.
• Defined by the number of teeth on each ring:
  • Standard: 53 teeth (outer), 39 teeth (inner)
  • Semi-compact: 52 teeth (outer), 36 teeth (inner)
  • Compact: 50 teeth (outer), 34 teeth (inner)
• Performance:
  • Standard setup has the hardest gears.
  • Compact setup offers the easiest gears for climbing.

Cassette

• Group of cogs located on the rear wheel.
• Typically includes 9-12 cogs ranging from 11 to 32 teeth.
• Determines the bike's speed classification (e.g., 9-speed bike).

Derailleurs and Shifters

• Derailleurs shift the chain between rings (front) and cogs (rear).
• Operated by shifters on the handlebars:
  • Left shifter controls the front derailleur.
  • Right shifter controls the rear derailleur.

Gear Ratios

• Expressed as: Number of teeth on chain ring : Number of teeth on the cassette cog.
• Determines wheel rotations per pedal stroke:
  • Example: A 52-tooth ring and a 12-tooth cog gives a ratio of 52/12 = 4.3 rotations.
  • Higher ratios result in greater distance per pedal stroke.
  • Lower ratios are beneficial for climbing with less distance but higher cadence.

Choosing the Right Gearing

• Compact or semi-compact setups are suitable for climbing enthusiasts.
• Standard setups are ideal for flat terrain or racing.
• Preference is based on rider's cadence:
  • High cadence riders might prefer modern compact setups.
  • Traditional setups suit low cadence riders.
  • Example: Lance Armstrong, a high cadence rider, used specific gear ratios for climbing in races.

Conclusion

• Selecting the right gear setup is crucial for optimizing performance based on riding style.
• Consider personal preferences and terrain when choosing bicycle gears.