In a bicycle, is the front wheel pushing the rear wheel or the rear wheel pushing the front wheel?

Is the big gear pushing the small gear or the small gear pushing the big gear?

What is the relationship between the size of the gear and the chain?

What's the use of so many gears behind a variable-speed bicycle? What does it have to do with the chain?

How many turns does the pedal turn and how many turns does the gear turn? How many times does the tire turn? What does it have to do with the distance traveled?

1. Except for the early bicycles, almost all bicycles are driven by rear wheels at present, and the front wheels only play the role of inducing steering (the front wheels actually have many functions, but as far as riding itself is concerned, it is steering).

2. The big gear is coaxial with the central shaft. When the pedal drives the central shaft to rotate, it also drives the big gear to rotate. The big gear transmits power to the small gear through the chain to make it rotate, that is, "the big gear drives the small gear" (note that it is not pushing).

3. The size of the big gear or the small gear has nothing to do with the chain, and the chain only plays a driving role.

Answer the last two questions together.

The pedal, the central shaft and the big gear are all on the same axis, so the big gear rotates as soon as the pedal rotates;

The number of teeth of the big gear is directly proportional to the number of teeth of the small gear, and the number of teeth of the big gear is n times that of the small gear, so the big gear rotates once and the small gear rotates once;

The pinion, the rear axle and the rear wheel are on the same axis, and the pinion rotates once and the rear wheel rotates once;

The large gear set of the gearbox is composed of a plurality of large gears with different sizes, and the small gear set is also composed of a plurality of small gears with different sizes. Large gears with different sizes will drive small gears with different sizes to have different speeds, which will play a role in speed change.

Let's actually calculate the number of teeth of the big gear: the big gear 48 and the small gear 40.

Number of pinion teeth: six disks 14, five disks 16, four disks 18, three disks 20, two disks 24 and a large disk 28.

Transmission ratio = number of teeth of front gear/number of teeth of rear gear = circumference of front gear/circumference of rear gear.

Large plate with small plate, the pedal rotates once, and the forward distance is xcm (calculation method: number of teeth of large gear ÷ number of teeth of small gear × tire diameter ×3. 14, the same below);

The quotient obtained by dividing the number of teeth of the big gear by the number of teeth of the small gear is called "transmission ratio". Under the same pedaling frequency, the greater the transmission ratio, the faster the riding speed, but the more laborious it is, which is suitable for flat sprint. Similarly, the smaller the transmission ratio, the slower the speed, but also the more labor-saving, suitable for climbing.