⚙️ Planetary Gear Hub: Fourteen-Speed Ratio Ladder and Willis Kinematics (2D)

2D lab for a fourteen-speed planetary bicycle hub. Pick a gear, cadence, chainring, sprocket and wheel size to see road speed, ground force and hub losses, and watch one planetary stage turn with sun, carrier and ring speeds given by the Willis equation. Uses the same ratio table and tooth counts as the 3D page, with four in-page numerical checks.