First count the number of front gears (not the number of teeth). There are four types of 1/2/3/4, four of which are not commonly used.

Count the number of flywheel blades later (not the number of teeth). There are several kinds of single knives: 5/6/7/8/9/ 10, of which 10 is not commonly used.

Multiply the number of gear pieces in the front by the number of flywheel pieces in the back, which is the series of this car.

For example, there are 3 front gears and 7 rear flywheels, so: 3*7=2 1 speed, and this car is a 2 1 speed gearbox.

For example, the front gear is 1 piece and the rear flywheel is 1 piece, so: 1* 1= 1 speed, this car is a single-speed car. We ride single-speed cars everywhere on the main road.

Bicycles, also known as bicycles or bicycles, are usually small land vehicles with two wheels. After people get on the bus, they are green and environmentally friendly vehicles powered by pedaling. British bicycles. Where bi stands for two, and cycle stands for wheels, that is, a two-wheeled vehicle. In China, Taiwan Province Province and Singapore, it is usually called "bicycle" or "bicycle"; In Hong Kong and Macao, it is usually called "bicycle" (in fact, it is generally called in Cantonese); In Japan, it is called "self-transfer". There are many kinds of bicycles, including single bicycle, double bicycle and multiplayer bicycle.

It can be used as an environmentally friendly means of transportation and tourism; More and more people use bicycles as fitness equipment for riding and cycling. Cycling itself is also a competitive sport, including road cycling, mountain cycling, track cycling and acrobatic cycling.

Bicycle is a traditional industry with a history of 100 years. Due to environmental protection and traffic problems, bicycles have once again become a favorite transportation and fitness tool for residents in all countries of the world, especially in developed countries. The focus of the world bicycle industry is shifting from traditional means of transportation to sports, mountains and leisure. In developed countries such as the United States, Europe and Japan, bicycles are common products for sports, fitness, leisure and entertainment. There is a great demand for bicycles all over the world every year. According to the statistics of Japanese CYCLEPRESS, the global demand for bicycles remains at the level of 65.438+0.06 billion, and the annual turnover of bicycles is about 5 billion US dollars.