The valve core on the inflatable inner tube, similar to a one-way valve, only allows the gas to enter, does not allow the gas to leak out, can facilitate the intake of air, and ensure the sealing of the inflatable inner tube.
This device, commonly known as the "kowtow worm", is an important part of the bicycle hub (commonly known as the tower base), which is a ratchet mechanism that can only rotate in one direction and will lock in r e v e r s e.
The transmission part of the bicycle is a chain mechanism, and its transmission device includes: active gear (wheel), passive gear (flywheel), chain and transmission. Gear ratio and transmission ratio is related to the efficiency of the use of the bicycle, in general, the number of teeth of the wheel gear is more than the number of teeth of the flywheel, that is to say, every time a person pedals a week, the number of passive gear turns will be more than one week.
The flywheel is the passive gear at the rear end of the bicycle chain, which has an internal thread inside in order to fix it at the right end of the rear axle, maintain the same plane with the sprocket, and connect with the sprocket through the chain to form the drive system of the bicycle.