You may not know these things about bicycles
Most bikes are currently divided into six main categories: utility, tourism, racing, mountain, hybrid and off-road. In developing countries, utility bicycles are the basic means of transport, and hundreds of millions of bicycles are being used in these countries. In developed countries, children or adults use utility bikes for short trips. They have heavy frames, flat handlebars, wide tires and seats, simple brakes, and usually a single speed. They weigh more than 14 kg, are rugged, easy to maintain, and inexpensive.
There are several other types of standard bicycles. Recumbent bikes allow riders to sit down a short distance from the ground, with foot-controlled drive cranks attached to a horizontal tube. For riders who are uncomfortable riding on a traditional bike, a recumbent bike is recommended. There is no standard design for recumbent bicycles, but the wheelbase is usually extended and the size of the front wheels is reduced. This design reduces wind resistance. Other types, such as tricycles, have two rear wheels to improve stability and are usually used by young children and seniors; cooperative bicycles, where two riders sit back and forth, and the front rider is responsible for steering and fixing the bicycle.
Practical bicycles often use reverse wheel brakes (Figure 1)-the brakes are applied by reversing. In developing countries, link brakes are often used. This brake uses pure metal connecting rods instead of brake wires. The front and rear brakes of other bicycles are controlled by a cable connected to the brake lever on each handlebar. The clip brake (Figure 2) applies the brakes by squeezing the sides of the two pads. There is an uncommon drum brake (Figure 3), which uses the brake transmission mechanism to make the brake shoes press the brake pads against the inside of the brake drum, thereby generating braking force, decelerating the wheels as required or at the shortest Stop within distance to ensure driving safety and ensure that the car is parked reliably and cannot slide automatically. Disc brakes (Figure 4) are designed for mountain bikes. When braking, the high-pressure brake fluid pushes the brake pad to clamp the brake disc to produce a braking effect.