Feature explained
Internal Gear Hub vs Derailleur Gears
Gears sealed inside the hub, versus the familiar external derailleur.
Simplified schematic — not to scale.
What it is
An internal gear hub packs several gear ratios inside a sealed hub shell, protected from weather and grit, and can shift while stationary. A derailleur system exposes the gearing on a cassette, offering a wider range and lighter weight, but more exposure to the elements.
Why it matters
Internal hubs suit low-maintenance commuting in bad weather; derailleurs suit riders who want the widest range and lightest setup for varied terrain.