Basic knowledge of bicycles.

Bicycles, also known as bicycles or bicycles, are usually small land vehicles with two wheels. After people get on the bus, it is a kind of green and environmentally friendly means of transportation driven by pedaling. Bi means bicycle or bicycle in English, while cycle means wheel. In Japan, it is called "bicycle"; In Chinese mainland, Taiwan Province Province and Singapore, it is usually called "bicycle" or "bicycle"; In Hong Kong and Macau, it is usually called "bicycle".

principle

Bicycle frame, tires, pedals, brakes, chains and other 25 components, the basic components are indispensable. Among them, the frame is the skeleton of the bicycle, which bears the largest weight of people and goods. According to the working characteristics of each component, it can be roughly divided into guiding system, driving system, braking system: 1, and guiding system: composed of handlebar, front fork, front axle and front wheel. The rider can change the driving direction and keep his body balanced by manipulating the handlebar.

2. Drive (transmission or walking) system: It consists of pedal, central shaft, toothed plate, crank, chain, flywheel, rear wheel shaft and rear wheel. Pedal drives people's pedaling force through crank, sprocket, chain, flywheel, rear axle and other parts, thus making the bicycle move forward continuously.

3. Brake system: composed of brake parts, the cyclist can control the brakes at any time to slow down and stop the running bicycle to ensure driving safety.

In addition, for safety and beauty, as well as from a practical point of view, it is also equipped with car lights, brackets and other components.

form

Body parts

Comprises a frame, a front fork, a handlebar, a seat, a front fork and the like, and is the main body of a bicycle.

Transmission part

Comprises a pedal, a crank, a sprocket, a chain, a central shaft, a flywheel and the like, wherein the pedal is stepped by manpower, and the wheels are driven to rotate through transmission parts, so as to drive forward.

Action part

That is to say, the front wheel and the rear wheel, including front wheel and rear wheel axle parts, spokes, rims (rims), tires, etc.

Safety instruments/devices/equipment

Including brakes (brakes), lights, bells, reflective devices, etc.

According to the need, some accessories can be added, such as brackets, clothes hangers, safety forks, fenders, air pumps, etc. In addition, sports cars, racing cars and mountain bikes equipped with speed change mechanisms are also equipped with speed change controllers and front and rear derailleurs.

classify

Road bike

For vehicles used on smooth roads, due to the low resistance of smooth roads, the design of road bicycles pays more attention to high speed. They usually use downward curved handlebars that can reduce wind resistance, narrow high-pressure low-resistance tires, higher gears and larger wheel diameters than ordinary mountain-climbing off-road vehicles. Because the frame and accessories don't need to be reinforced like mountain bikes, they are usually light in weight and efficient when riding on roads. Because the frame does not need to be reinforced, and it usually adopts a simple and efficient diamond design, the road bike is the most beautiful bicycle.

Track bike

A bicycle used on an extremely smooth oval track indoors has no brake, gearbox and reversible flywheel. Triathlon/Time Trial bicycle Road bicycles used in triathlon and time trial sports. The biggest feature of triathlon and time trial is that pulling force is not allowed, that is to say, the rider must overcome the air resistance by himself, and can't ride behind other riders. Therefore, the design of triathlon/time trial bicycle pays great attention to keeping the rider in riding posture to reduce air resistance. Triathlon bicycles also allow athletes to use similar muscle groups when riding, which makes it easier to switch from riding to running.

mountain bike

Mountain biking originated in San Francisco in 1977. Vehicles designed for mountain riding usually have a transmission that can shift gears in a labor-saving or fast way. Some will install shock absorbers on the frame, and some tire treads are chocolate patterns to facilitate riding on unpaved roads. The dimensions of mountain bike parts are generally in English units. The rim is 24/26/29 inches, and the tire size is generally 1.0-2.5 inches. The frame size is also expressed in English units, such as 14 inch, 17 inch and 19 inch.

Downhill bike

Downhill bike, also known as downhill bike. English abbreviation DH. This is a very challenging activity. Riders use special DH bicycles to slide on the hillside and even go down the mountain to seek excitement. Most activities are carried out on ridges, mines and snow. The Austrian used DH to set a world record of 210.4 km/h/h. The frame angle of downhill bike is different from that of mountain bike, and the parts are in English units like mountain bike. Please wear a helmet, armor and other equipment when doing this activity. The damping stroke of the front fork is longer than that of mountain bikes and XC bicycles. Tire width is generally more than 2 inches.

Horizontal bicycle

A bicycle that is completely different from the traditional design. There are usually large and comfortable seats with two or three wheels. Its advantages are comfort and low wind resistance.

Tour bike (tour)

It is developed from road bike, suitable for ultra-long-distance self-sufficient travel, with a more comfortable and relaxed frame geometric design, capable of carrying loads, with a very low lowest gear, using wider tires, pursuing reliability and durability in the choice of accessories, rather than focusing on reducing weight, and often using mountain bike pedals.

Advertising bicycle (advertising bicycle)

Advertising bicycle is a special bicycle (ZL2007 2 03 12 144.6) made of thin-shell frame authorized by China National Patent Office, and it is a professional advertising bicycle that uses the surface area of the frame to publish advertisements.

Cross country cycling race

It developed from the road bike, and originated from the rider's wish to conquer both roads and mountains with one bike, so the rider chose a stronger road frame and wheels, installed a stronger brake and wide tires, and used a mountain bike pedal. Off-road vehicles can not only drive at high speed on expressways, but also have certain off-road capabilities.

A tandem bike, also known as a tandem bike, is driven by more than two people, and the direction is controlled by the first person.

collapsible/folding bicycle / bike

It is a vehicle designed for easy carrying and loading in the car. In some places, public transport such as railways and aviation allow passengers to carry foldable bicycles with them.

Electric bicycle (motor bicycle)

An environmentally friendly electric vehicle driven by half power and half manpower. The electric bicycle can automatically detect the force exerted by both feet, assist pedaling with appropriate force when necessary, and automatically adjust the force. In China, Guangzhou and other areas, the use of electric bicycles is prohibited due to problems such as battery recycling.

Bicycle bmx

A bicycle specially used for extreme sports. In order to be more suitable for stunts, this kind of bicycle has made many modifications, such as lighter body, no brakes, and the handlebar can rotate 360 degrees.

ingredient

1. The frame component is the basic structure, skeleton and main body of a bicycle, and other components are directly or indirectly installed on the frame.

There are many structural forms of frame parts, but they can be divided into two categories: men's frames and women's frames.

The frame is generally composed of ordinary carbon and copper pipes welded together. In order to reduce the weight and improve the strength of steel pipes, low alloy steel pipes are used in high-grade bicycles. In order to reduce the resistance of fast driving, some bicycles also use streamlined steel pipes.

Because the bicycle runs by the driving force and riding skills of the human body, the frame has become an important structure to bear the impact load generated when the bicycle runs and whether it can carry the human body comfortably and safely. The manufacturing accuracy of frame parts will directly affect the safety, stability and lightweight of vehicles. Generally speaking, spokes have the same diameter. In order to reduce gravity, spokes with large ends and small middle are also made into spokes with variable diameters. In order to reduce air resistance, spokes are made into flat streamlined downhill bicycles.

2. Outer tires: There are two kinds of soft tires and hard tires. The cross section of the soft sidewall tire is wide, which can completely wrap the inner tube, and the landing area is relatively large, which is suitable for driving on various roads. Hard-edged tires have the advantages of light weight, small landing area, low resistance and light driving.

The pattern on the tire is to increase the friction with the ground. The tire width of mountain bike is particularly wide and the pattern is deep, which is also suitable for cross-country mountains.

3. Pedal assembly: The pedal assembly is assembled on the left and right cranks of the middle axle assembly, and is a device that converts horizontal force into rotational force. When a bicycle is riding, the pedal force is first transmitted to the pedal assembly, and then the pedal shaft rotates the crank, the toothed plate, the central shaft and the chain flywheel, so that the rear wheel rotates, thus making the bicycle move forward. Therefore, whether the structure and specifications of the pedal assembly are suitable will directly affect whether the rider's foot position is suitable and whether the bicycle can run smoothly.

Pedal: It can be divided into integral pedal and combined pedal. No matter what style of pedal, it must have a pedal surface, which is safe and reliable, has certain anti-skid performance, and can be made of rubber, plastic or metal materials. The pedal must turn flexibly.

4. Front fork assembly: The front fork assembly is located at the front of the bicycle structure, and its upper end is connected with the handlebar assembly, the frame assembly is matched with the front tube, and its lower end is matched with the front axle assembly to form the guiding system of the bicycle.

Turning the handlebar and the front fork can change the direction of the front wheel and play a guiding role in the bicycle. In addition, it can also play a role in controlling the running of bicycles.

The force of the front fork is a cantilever beam, so the front fork must have sufficient strength and other properties.

5. Chain: Chain, also known as cart chain and roller chain, is installed on the coupling wheel and flywheel. Its function is to transfer pedal force from crank and sprocket to flywheel and rear wheel to drive the bicycle forward. Sprocket: made of high-strength steel to ensure the required tension.

6. Flywheel: The flywheel is fixed at the right end of the rear axle with internal thread, keeps the same plane with the sprocket, and is connected with the sprocket through a chain to form the transmission system of the bicycle. Structurally, it can be divided into two categories: single-stage flywheel and multi-stage flywheel.

Single-stage flywheel, also known as single sprocket flywheel, is mainly composed of jacket, flat block and core, jack, jack spring, washer, steel wire block and several steel balls.

The working principle of single-stage flywheel is that when the pedal is stepped forward, the chain drives the flywheel to rotate forward. At this time, the inner teeth of the flywheel and the jack are contained, and the rotating force of the flywheel is transmitted to the movement through the jack, and the movement drives the rear wheel axle and the rear wheel to rotate, so that the bicycle can move forward. When the pedal stops, the chain and the jacket do not rotate, but the rear wheel still drives the movement and the jack to rotate forward under the inertia. At this time, the internal teeth of the flywheel slide relatively, so that the movement is pressed into the gap of the movement, and the jack compresses the jack spring. When the tooth top of the jack slides to the inner tooth top of the flywheel, the jack spring is compressed to the maximum. When it slides forward a little, the jack spring bounces to the tooth root and makes a "click" sound. The core rotates faster, and the jack slides quickly on the inner teeth of each flywheel, making a "click" sound. When the pedal is stepped in the opposite direction, the jacket will rotate in the opposite direction, which will accelerate the sliding of the jack and make the "click" sound more urgent. Multi-stage flywheel is an important part of bicycle transmission.

On the basis of single-stage flywheel, multi-stage flywheel adds several flywheel blades, which are combined with the sprocket on the central shaft to form various transmission ratios, thus changing the speed of bicycle.

fundamental characteristics

The performance of bicycles can be measured from three aspects: riding, safety and durability.

Riding performance is related to the structural size of bicycles. Only when the rider's body material matches the vehicle can he ride briskly, comfortably and freely. The human body and the vehicle contact at point A, point B and point C3, which form a triangle, and its side length and angle are important parameters of the bicycle. The length of AB and AC is related to whether the rider can exert his physical strength most effectively. The length and position of BC depend on the vehicle model and the rider's habits, which determines the rider's posture and comfort.

The center distance L between the front and rear wheels, the inclination angle θ of the front fork and the extension distance T of the front fork are also the main parameters of the bicycle, which are selected according to the vehicle type. Generally speaking, when L and T are large and θ is small, the stability of the vehicle is good, and the self-recovery of straight driving is strong, but the flexibility is poor. On the contrary, when the values of L and T are small and θ is large, the vehicle has strong flexibility and poor stability. L value is selected according to the cyclist's body material, generally 900 ~1200mm; θ value is 65 ~ 75; The value of t depends on the value of θ. The camber angle h of the front fork is usually controlled at the intersection point j between the steering axis of the front fork and the vertical line of the front wheel center, and the height of the point j from the ground is generally 15% ~ 60% of the wheel radius r. In addition, manufacturing accuracy and wheel weight (including tires) also affect riding performance.

safety performance

The personal safety of cyclists is an important issue, and various countries have formulated corresponding standards. The safety standards issued by China include the strength of structural components, braking performance of brakes and safety devices. The former includes the strength of frame and front fork assembly, the assembly firmness of handlebar and front fork and the strength of front and rear wheels. ① Impact strength of frame and front fork assembly: There are two measuring methods. Firstly, the drop impact test was carried out, the assembly was erected vertically, and a 22.5kg heavy hammer was placed above the front fork180 mm. Under the impact of a heavy hammer, the permanent deformation of the assembly should not exceed 40 mm, and there is no visible crack; The second is the drop impact test. In this test, a weight of 70kg is placed on the saddle of the assembly, so that its center of gravity moves to the vertical position of the rear axle and falls forward freely. After repeated testing twice, no cracks can be seen with naked eyes. In addition, the frame and front fork need to be tested for transverse load strength, and their load weights vary with the vehicle models.

② Assembly firmness of handlebar and front fork: The measurement method is to apply a torque of 25N·m to the handlebar transverse tube (generally replaced by a test bar) after the handlebar is installed in the front fork, and the handlebar is not allowed to rotate.

③ Strength of front and rear wheels: The measurement method is to clamp and place the spoke and correct the flat wheel, and apply a force of 178N in its transverse direction. After 1 min, the permanent deformation shall not be greater than1.5mm. ..

(4) Braking performance of the brake car: The test methods are divided into two types according to the speed ratio of the vehicle. First, it is stipulated that the test speed of bicycles with a journey of more than 5 meters is 24 km/h; The other is for cars with a journey less than 5m, the speed is 16 km/h, and there are two kinds of braking performance: dry state and wet state simulating rainy days. At the specified test speed, when the front and rear brakes are used at the same time, the braking distances in dry state and wet state should not be greater than 5.5m and 15m respectively. ⑤ Safety device: Bicycles should be equipped with bells or lights, and also have reflectors (commonly known as reversing lights). The reflector is illuminated by the headlights of the motor vehicle or other external light sources, reflecting enough light to remind the other party to pay attention, thus protecting itself. There are three kinds of reflectors: front reflector, side reflector and back reflector. The front is white, the rear is red, the front wheel is white or amber, the rear wheel is white or red, and the pedals are white or amber.

persistence

It can be divided into internal and external aspects. The inherent durability requires a certain structural strength. Some parts that are easy to wear, such as bowls of front, middle and rear axles, teeth of flywheel, chain cores and rollers, and parts of foot brakes, need heat treatment, carburization and quenching to improve the surface hardness. The durability of appearance is to prevent corrosion and improve appearance by electroplating and painting (painting). Electroplating is to plate copper, nickel, chromium or nickel, nickel, chromium on the original metal surfaces such as handlebars and rims. Other coatings can be selected according to the resource situation and antirust performance requirements. For some minor small parts, bright zinc plating process is adopted. Spray painting is to spray the surface of the frame and front fork by high voltage static electricity. The paint surface should be plump and gorgeous, and have certain antirust performance and paint film binding force.

development trends

Because of the differences in living standards in different countries, the purpose of using bicycles is also different. In some countries, cyclists mainly use multi-speed vehicles, off-road vehicles and mountain bikes for travel, exercise and children's sports. Bicycles in some countries are mainly used as means of transportation, and light vehicles and multi-speed vehicles are used more. Generally speaking, bicycles are developing in the direction of beauty, portability, firmness, novelty and cheapness. Beauty is beautiful in appearance, colorful, gorgeous but not vulgar; Light means light weight and light riding; The intensity of prisons is very high; New styles and varieties; Cheap means low cost and strong competitiveness.

Lubrication of bicycles

Bicycle is a large-scale and wide-ranging human machinery. The types of lubrication structures include sliding friction and rolling friction, small amount of friction and linear friction, fluid lubrication and boundary lubrication, and oil lubrication and grease lubrication.

The key moving friction parts of bicycles are the central axle, the front axle and the rear axle. They all use ball bearings and are lubricated with No.2 calcium-based grease. During each overhaul, clean the ball, bead groove and cover, evenly apply No.2 calcium-based grease in the bead groove, and fill the special ball (bead) with smooth and complete surface and uniform particles around the shaft, and then cover it to avoid mixing dust and impurities. Then drop 2-5 drops of bicycle lubricating oil or low-viscosity lubricating oil with viscosity of 7- 15mm2/s at 40℃ into the oil injection hole (with oil hole) or shaft end every quarter or half a year. However, before refueling, dust and dirt near the refueling hole or shaft end must be removed to avoid wear. Generally, lubricating oil cannot be mixed when lubricating with grease, and oil and grease cannot be mixed under normal circumstances. However, it is a special case on bicycles. In order to simplify the equipment, there is no grease nozzle, only lubricating oil is added to improve lubrication.

Secondly, the lubrication of chain and gear plate, here is the mixed friction of sliding friction and rolling friction, and most of them are in the state of boundary lubrication, so the friction conditions are harsh, so it is necessary to use lubricating oil with good adhesion and lubricity, especially most of them are open and work in dusty conditions, which seriously damages the chain and gear plate, so it is necessary to clean them at any time (every quarter or half a year) according to the situation and use new oil, and most of them use high-viscosity lubricating oil (44

Normal riding does not require any technology, but it is the most important and basic item in bicycle maintenance. Before riding a bicycle, it is very important to check the condition of the bicycle, which is often forgotten. Therefore, before riding, remember to do the following checks:

Check the size of riding posture: If you are not riding your own car, please remember to adjust the seat cushion to the appropriate height before riding.

Check the tightness of screws in each part: check whether the quick release of the front and rear wheels and the seat cushion lever is locked, check whether the handlebar is fixed and whether other screws are loose.

Check the tire: check whether the tire pressure is sufficient, if not, inflate it to an appropriate pressure, check whether there are cracks in the tire wall, whether the cut tire tread is too shallow, and replace the outer tire if necessary.

Check the brakes: Try to pull the front and rear brakes to check whether the brakes can stop.

Check the front wrist: press the front brake and shake your body back and forth. If there is any shaking gap, it means that the front wrist needs to be readjusted.

Check the transmission: after starting, try to change the front transmission and the rear transmission respectively, whether it can be smoothly changed to various speeds and whether there will be strange noise.

Precautions for riding a bicycle

In order to prevent waist discomfort caused by cycling, the following points must be noted:

1. If the seat is too hard, you can cover the seat with a soft seat cover made of foamed plastic to reduce the friction between the seat and the lower part.

2. Adjust the height and angle of the seat. If the seat is too high, the hips will inevitably move left and right when riding, which will easily cause scratches on the lower part of the club; The front of the car seat is facing up, which is more likely to damage the lower part.

3. When riding for a long time, you should pay attention to changing the riding posture to move the center of gravity of your body to prevent you from focusing on a certain point in the lower part for a long time.

4. When riding the gearbox for the first time, don't be too fast and too long, and then accelerate and timeout after the body adapts.

5. When riding a bike, if you find that there are discomfort symptoms in the lower part of the club, you should find out the reasons in time. If there is a problem with the seat, it should be eliminated or improved in time, and pay attention to rest. After the symptoms are eliminated, ride a bike; If you can't eliminate the symptoms, you should go to the hospital and ask a doctor for examination and treatment.

Maintenance type

Short-term fixed term

Frequent short-term maintenance. If you use your bicycle normally, the maintenance at this stage is quite simple, and this maintenance can keep your car in good condition, so you must never ignore it. Cleaning the car: cleaning the car can not only keep your car shining when it is new, but also avoid the corrosion of the frame. If you ride in heavy rain or mud, you should clean it as soon as possible after riding. When washing the car, you should pay attention to the following points: if there is not much sludge on the car body, or most of it is dust, you can clean it with a rag or brush it with a big brush. Do not use high-pressure water column to clean the sludge on the car body. Although this method is very effective, it may force sewage into the bearing, which may lead to bearing damage. In the case of a large amount of sludge on the car body, the sludge should be washed with a brush and soapy water, then washed with clear water and dried with a cloth. Remember to check whether the paint falls off after the car is cleaned. The steel frame will begin to rust after peeling off, while the aluminum alloy or carbon fiber and titanium alloy frame will not rust, which will only affect the appearance. After washing the car with water, remember to dry the chain and oil it again. Check the brake pads: remove impurities from the brake pads to ensure their braking force. If it is badly worn, it must be replaced. Re-oil the conduit: If the braking or gear shifting action is not good, the friction between the inner and outer wires may be too great. Remove the outer steel wire from the pipe block, coat the inner steel wire with butter, and then reinstall it. If the operation is still unsatisfactory after that, please consider replacing the inner and outer catheters. Oiling the chain: After dripping the lubricating oil on the chain, wipe the oil on the outside of the chain about ten minutes later. As long as there is oil in the moving parts inside the chain, the extra lubricating oil outside will stick to dust, which will increase the trouble of cleaning, so it is best to wipe it clean. In addition, if you use spray tank oil, please remember to wipe off the oil dripping on other parts after refueling.

Mid-term periodic maintenance

Check the chain: the chain will stretch after long-term use. The pitch of the chain is 0.5 inch. When measuring 24 chains, the length should be 12 inch. If the length exceeds the normal length 1/8 inches, replace the chain.

Cleaning the chain: If there is a lot of sludge on your chain, it may be time to clean it. You can clean the chain with a chain cleaner, or remove the chain, find a container, fill it with solvent oil, put it in the chain, shake it and clean it, and finally take it out to dry and oil it.

Check the flywheel and the big toothed disc: if the flywheel has tooth jumping after the chain is updated, please update the flywheel; If the teeth of the big toothed disc are seriously worn and the chain is stuck, it should also be replaced; Check the fixing screws of the big toothed disc; If it is loose, it must be locked again.

Check the rim: check whether there are slight cracks near the gas nozzle hole and the steel wire hole. If there is a crack, replace the rim as soon as possible, lift the wheel, turn the wheel, and observe whether the rim will rub the brake pad. If so, please readjust the rim.

Check the steel wire: check whether the steel wire of the front and rear wheels is broken, and replace it if it is. After replacing the steel wire, the rim must be readjusted. Observe the deflection direction of the rim when adjusting the rim. If it leans to the right, please loosen the right wire near the rim and lock it on the left, and vice versa. The left and right deflection amplitude of the rim should be less than 2mm.

Check the driver: check whether the driver is deformed in the car accident and whether the locking part of the elevator is cracked. If so, please update the driver.

Check the seat cushion and seat cushion rod: Remove the seat cushion rod and check for deformation or cracks. If not, spread a thin layer of butter on it and put it back. Check whether the seat cushion is damaged and whether the bracket under the seat cushion is in good condition. If there is any problem, please replace it.

maintenance and repair

Check the wheel hub: remove the front and rear wheels, check whether there are cracks near the steel wire hole, and replace them immediately if there are any. Turn the hub shaft by hand to see, and then shake it up and down. If there is any gap, or it is very loose, please remove the hub shaft, clean up the oil inside, then reload the new butter and reassemble the hub shaft. Remember to adjust the bearing so that the shaft can rotate smoothly, but there will be no gap between up and down shaking.

Inspection center: Take off the chain, grab the crank and shake it left and right. If it shakes, lock the fixing screw. If it still shakes, adjust the center bearing. Put your ear on the seat cushion and turn the crank. The sound you hear should be a steady "whirring sound". If you hear abnormal sound or other strange sounds, it means that the bearing is damaged and the center should be replaced.

Check the pedal: remove the pedal, use an open-ended wrench of 15mm, pay attention to the left pedal, and do not remove it by mistake. The pedal bearing does not need to be adjusted, but it still needs to be checked. If a box pedal is used, check whether its mechanism works normally and is lubricated. Check the transmission: check whether all moving parts of the transmission will shake. If so, it means that the transmission is badly worn and should be replaced. Otherwise, lubricate the moving parts with oil.

Maintenance of shock absorber: Before hydraulic shock absorber, remove wrist and replace it with new shock absorber oil. If it is egg yolk, check whether the egg yolk is cracked or deformed, and update it if it is. The original purchaser should be consulted for the maintenance of the shock absorber.

Check the frame: check all the paint. If the frame rusts to the point of perforation, it must be replaced. If the frame is deformed due to impact, it should also be replaced.

Update all internal and external conduits: All conduits have worn out after long-term use, so it is recommended to replace them to maintain their performance.

When riding a bike in the wild, the car broke down, which made you have to walk home. This is really a disappointing thing. Therefore, in order to avoid this situation, you must remember to bring tools when you go out to ride a bike. Don't assume that the accident won't happen. It is always good to be prepared.