What is the tooth ratio of a bicycle, and what is the tooth ratio of a professional rider?

The transmission system is the main component of the modern bicycle, which is mainly composed of the front tooth disk, the rear flywheel, the chain, the chain lever and the control rod. He determines how hard you stomp and how fast the wheels turn.

Take 50/34t(dental disc) and 11-32(flywheel) for example (t stands for teeth and 34t means 34 teeth on the dental disc). 50/34 refers to the anterior dental disc consisting of two discs with 50 (outer) and 34 (inner) teeth respectively. The 11-speed flywheel 11-32 means that the rear flywheel is 11 speed, with 11 teeth discs, the minimum number of teeth on the disc is 11 teeth, and the maximum number of teeth on the disc is 32 teeth.

Tooth ratio: the number of teeth of the current disc and the number of teeth of the flywheel. When the front disc is at 50 teeth and the rear flywheel is at 11 teeth, the tooth ratio at this time is: 50÷11, that is, 4.55. This means that for every lap you tread, the rear wheel turns 4.55 laps, which is the most strenuous tooth ratio and usually only used on flat and downhill roads. When your front disk is at 34 teeth and your back flywheel is at 32 teeth, it means that your tooth ratio is 34÷32=1.06. That means every time you step on the back wheel, it turns. This is usually used for steep climbing sections.

The larger the tooth ratio value of the front and rear gears, the more laborious it will be.

A concept inseparable from the transmission system is pedal frequency. When you ride at a gear ratio of 36 (disc teeth) *17 (flywheel teeth), your pedal rate is 90 RPM, so you will be moving at a speed of 24 km/h. If your tooth ratio is 52*12, then you can achieve a speed of 24 as long as you ensure a step frequency of 45 RPM.

The right tooth ratio is where you find a balance between strength, endurance and equipment.

What do professional drivers use? Professionals often use high-speed gears with 55×11 teeth for time trials. On flat or downhill stages, they may have 53/39T sprocket blades and 11-21T flywheels. If it's a climbing stage, they switch to a 23T or 25T flywheel.

Fixed tooth single-speed bicycle: Unlike variable speed bicycles, fixed tooth single-speed bicycles usually refer to single-speed bicycles with only one flywheel. These cars usually have only one disc and flywheel, and the tooth ratios are usually 44/16 and 46/16, with the first number representing the number of teeth on the disc and the second number representing the number of teeth on the rear flywheel.

Compared with the variable speed bicycle, the single-speed bicycle will be lighter than the variable speed car 1-1.5 kg, and because there is no transmission, shift lever and other excess cables, the single-speed car is easier to maintain, and there is no need to learn how to change the gear correctly. The chain stays straight and lasts longer.

When riding a single-speed bike, you usually need to pedal with more force than a variable speed bike. For example, when climbing a steep hill, you really have to push down the pedal hard. So the general track cyclists leg muscles are very developed.