Mainly talk about the structure of the bicycle:
1, front wheel; 2, spokes; 3, hub; 4, front fork; 5, front brake; 6, steel cable; 7, brake and shift handle; 8, handlebar; 9, vertical rod; 11, front shifting; 12, seatpost; 13, car seat; 14, rear brake; 15, shelf; 16, flywheel; 17, mirror; 18, rear wheel; 19, rear shift; 20, foot support; , valve; 22, rear wheel; 23, chain; 24, roulette; 25, pedal; 26, crank.
Several important concepts:
Transmission: including drive gear (wheel), driven gear (flywheel), chain and transmission.
Gear ratio: the ratio of the number of teeth of the driving gear (wheel) and the driven gear (flywheel);
Transmission ratio: the gear ratio is multiplied by the diameter of the rear wheel;
Transmission stroke: The transmission ratio is multiplied by the pi, which is the transmission stroke, that is, the distance that the bicycle advances every week.