Reference: Buy a unicycle

The shape and function of fork

Forks are mainly divided into flat-shouldered forks and oblique-shouldered forks (also called sliding-shouldered forks, willow-shouldered forks and round-shouldered forks) according to their shapes and whether their feet can be stepped on.

The diagonal shoulder car does not conform to the national unicycle code, and the bicycle fork shoulder is impossible. You can't step on the fork shoulder with one foot or both feet, which affects the training of body movements and hinders the improvement of human balance and coordination ability. It is difficult to play the level and potential of cyclists. Greatly reduced the appreciation of the performance. Because the top ends of the risers on both sides of the fork are arc-shaped, the elasticity is increased, the fork vibrates after being impacted, the stability is poor, and the legs of the fork are easy to separate outward, resulting in the bearing moving out of position. Therefore, high-end cars in Europe and America no longer use oblique forks.

Flat shoulder fork is divided into old flat shoulder and new flat shoulder. Simply understood as long as the fork shoulder can support the foot, it is called flat shoulder.

(1) The old flat shoulder is formed by stamping thin steel plate for many times through the die, and then pressed into the risers on both sides of the fork. For the sake of beauty, the interior of the riser is spot welded first, and then the fork riser is inserted and fully welded from the inside. The overall strength and left-right stability are not as high as the new flat shoulder fork. The fork shoulder is too smooth, and the left and right outer dimensions are small. People are prone to slip and fall when standing on the fork shoulder (the effect is better when the left and right external dimensions are greater than 100 mm). The absorption and shock absorption effect and durability are not as good as those of the new flat shoulder. Developed markets in Europe and America have basically eliminated the old flat shoulders. Only a few low-end cars are still in use.

_(2) The new type flat shoulder fork is welded integrally, with high integrity and stability and high bearing strength. The shoulders are uneven, non-slip, with good absorption and shock absorption effect, and the styles are beautiful and changeable, which can meet different eyes. Avoid aesthetic fatigue. High-end cars in Europe and America fully adopt new flat shoulders.

Bifurcated material, avoid lengthy introduction.

1; Titanium-infiltrated carbon fiber fork. Also known as titanium mesh carbon fork, it is light in weight, anti-corrosion and anti-oxidation. Expensive, less used.

Titanium alloy fork, light weight, high strength, corrosion resistance and oxidation resistance. Expensive. Mainly used in high-end cars.

Chromium-molybdenum steel fork has high strength, high temperature resistance, strong corrosion resistance, strong ability to resist external impact, not easy to be damaged, easy to process and shape, and the finished product is beautiful and durable. Widely used in high-end unicycle, bmx, mountain bike, mountain bike and other forklift racks. Replacing ordinary steel with Cr-Mo steel can greatly reduce the weight of finished products. The price is more expensive.

4; Aluminum alloy forks, forks are mainly made of high-strength, 6-series and 7-series aluminum alloys, such as 606 1, 7005 and 7075.

Light weight, medium strength, good corrosion resistance, good weldability, good process performance (easy extrusion) and good oxidation coloring performance. The price is higher.

Stainless steel fork; High strength, corrosion resistance and oxidation resistance. High surface finish, beautiful appearance, the surface can not be painted. The price is more expensive.

Manganese steel fork; Compared with ordinary steel, it has higher strength and slightly more expensive price.

7; Ordinary steel is divided into high carbon steel and low carbon steel, and inferior thin-walled low carbon steel pipes are generally used for inferior products. Low strength, poor corrosion resistance, poor quality of finished products, and need surface electroplating, painting and other treatments. Low price. When impacted by external force, it is easy to produce stress concentration, cause deformation and welding, and cause serious harm to people.

Trident surface treatment, the specific process will not be said, a brief description. Mainly for steel.

1; Electroplating. After the surface finish meets the requirements, it is treated with acid cleaning, and then put into electrolytic cell for copper plating and chromium plating. Inferior products have low surface finish, thin coating and low process level, and the electroplating grade is generally only 4 or 5. Even replacing chromium with nickel reduces the cost. Increasing the dosage of brightener increases the surface brightness, and the coating has poor adhesion, which leads to the coating being damaged (even falling off) and rusted in a short time. The inferior bicycle rims around 300 yuan often rust, which is the reason. Ordinary users are basically unrecognizable.

; Baking paint is divided into ordinary paint and electrostatic paint.

The surface of inferior steel pipe is pitted and uneven. Only put a layer of putty on it first, scrape it off and cover it, and then paint it. This is an ordinary baking paint, because there is putty between the surface of the steel pipe and the paint layer, and the paint adhesion is poor. Bumping or temperature difference often causes paint to fall off on its own, and putty can still be seen after falling off. Small workshops spray paint, and there are often bumps and sundries on the paint surface, which have color difference according to the light.

After passivation and phosphating treatment, the steel pipe with smooth surface can be directly painted with electrostatic paint. The paint layer is thin and uniform. Strong adhesion, basically the same color, no obvious color difference.

Fourth, don't talk about other aspects of the fork, pay attention to the quality of the trademark.

In short, if you can't identify yourself, buy regular products. Remember, good goods are not cheap, and cheap goods are not good. From Nanjing to Beijing, it is better to buy than to sell.

It is too late. Let's call it a day. I'm not checking either. Just post it directly.

Connection mode of bearing box

The bearing seat of unicycle is used to connect the axle, bearing and front fork into a whole. Limited by the structure and installation space of the unicycle itself, the bearing seat of the unicycle can not adopt the standard bearing seat, but can only be specially designed. The connection mode between the bearing seat and the front fork of unicycle has undergone three generations of changes. The connection of the first generation bearing seat is the worst, which has been completely eliminated by developed regions such as Europe and America. The second generation is slightly better, and there are few low-grade cars in use abroad. The third generation bearing seat stands out. Foreign high, medium and low-grade cars basically adopt the third generation bearing seat.

1; It is not easy for the first generation of bearing seats to say that they love you, and many riders suffer from it.

(1) The first-generation bearing seat was formed by stamping ordinary steel plates, and it was actually an iron shell. Simple structure, low cost, only a few cents each. Low strength and easy deformation. The lateral stability is extremely poor, which often causes the bearing to slip in the direction of cranks on both sides. Because of its brittleness, the stress produced by the root is concentrated, which is easy to cause metal fatigue, cracking and damage.

(2) It is difficult to disassemble when replacing the bearing, and it is difficult for the three grippers of the bearing puller to be stuck (caught) at the same time, so it is basically impossible for individuals to replace the bearing.

(3) It belongs to disposable articles, which will be deformed or damaged once disassembled. Only the complete set of bearings (which have been installed in the bearing housing) can be ordered from the manufacturer or seller by mail. Resulting in high replacement cost. It is almost impossible to replace a good bearing that you like.

(4) Because the joint between the first-generation bearing seat and the fork is flat, the corresponding position at the bottom of the fork has to be pressed into a flat shape during manufacturing, which greatly reduces the left and right stability of the fork. After the bottom of the fork is flattened, the mounting screw hole has only a few turns of thread, which is easy to slip.

(5) The only advantage is that the screw mounting opening on the bearing seat is rectangular, and the relative position of the wheel fork center can be adjusted during installation. In this way, the machining accuracy (length and width) of the fork can be greatly reduced. As long as the length difference between the vertical plates on both sides of the fork is less than 5 mm, the wheel can be adjusted to the center of the fork. There are some deviations in the size of the flattened part at the bottom of the fork, which will not affect the installation and provide convenience for some enterprises with poor technology and production capacity to process the fork.

2; The second-generation bearing seat was not widely used at home and abroad, and was quickly replaced by the third-generation bearing seat.

The second generation of bearing housing solved some shortcomings of the first generation.

(1) The bearing seat can be reused, so it is convenient to remove the bearing. Bearings can be purchased separately or locally.

(2) It is not easy to deform, and the integration with the front fork after installation is greatly improved compared with the first generation.

(3) Installation and disassembly are also very difficult, but slightly more convenient than the first generation. The inner side is easy to wear due to more disassembly times, which is not suitable for long-term use. What's more, it is made of plastic and extremely fragile. Cause a lot of harm.

3; Third generation bearing seat

The third generation bearing seat and front fork are welded as a whole, with high strength and good stability. The installation and disassembly are quick and convenient, and the bearing can be replaced at will, which is durable. It has been fully adopted by developed regions in Europe and America.

The only disadvantage of the third generation: the fork is required to have high machining accuracy, and the riser lengths on the left and right sides of the fork must be equal, otherwise the wheel deviation is incorrect. It requires high processing equipment and technology for producers.

The third trick to buy a unicycle-rims.

Trolley, rims, buy trolleys, rims, buy

The rim of a unicycle is very important, which not only bears the gravity of human body and the tension of spokes, but also bears the impact of the ground and obstacles. It can be said that it is squeezing down, pushing up and pulling left and right, and horizontal thrust torture. It is best to use ordinary wide circles for unicycles, especially off-road vehicles. Narrow ring and V-shaped ring (also called knife ring) have poor lateral stability, and when subjected to horizontal thrust in the left and right direction, the rim is easy to bend and be damaged (commonly known as folding ring). The quality of the rim should not be underestimated.

Brief introduction of rim materials

Titanium-infiltrated carbon fiber rims are extremely expensive and rarely used. Nylon steel ring is made of a layer of nylon plastic in ladle, including engineering plastic steel ring, aluminum casting steel ring, FRP and so on. The rims are used less, so I won't discuss them much, focusing on the commonly used steel rims and aluminum alloy rims.

Two. Aluminum alloy wheel rim is called aluminum wheel rim for short. The materials are different, so I won't go into details. Simply divided into high quality, ordinary and inferior. Three categories.

Aluminum rings are divided into single-layer and double-layer aluminum rings according to the structure.

(1) single layer has a slightly lower strength and is mostly used in ordinary occasions. At present, inferior rings are all single-layer rings, and the cost is extremely low. The price of inferior unicycle is 100 yuan, the price is inferior bicycle in 200 yuan, and the price of aluminum ring is between 7- 10 yuan according to the size. The material is extremely poor, and the ring wall is too thin and easy to be damaged.

Double-layer aluminum ring has high strength and good stability. Long life, more expensive, most of the prices are concentrated in 70-250 yuan. Mainly used for mid-to high-end cars.

(3) Surface treatment of aluminum ring. Passivation (surface oxidation to form a protective film), color coating, coloring, plastic coating, ceramic hardening (improving surface hardness), etc. Some will be sideways. The specific choice depends entirely on personal preference. The surface treatment is only to prevent oxidation and corrosion, and it looks beautiful. Don't pursue it deliberately, let it be. Otherwise, it will be fooled into paying more, and manufacturers and merchants often create concepts, selling points and malicious speculation. If you are not careful, you will be caught.

Three. Steel ring is called steel ring for short. The material, thickness and shape are all different, so I don't explain them one by one. Get to the point. Good rims are made of high-quality steel and are durable. The surface finish is high, and electroplating, electrostatic baking paint and even liquid baking paint are mostly used. Inferior steel rings are of poor material, thin wall and easy to be damaged. The electroplating grade is low, and even nickel is used instead of chromium to reduce the cost. Surface coating is easy to fall off and often rusts and corrodes. The paint is ordinary paint or even directly painted with ordinary metallic paint.

Four. Engineering plastic rim is called plastic rim for short.

Plastic rings have low strength, are particularly fragile, and are easily broken and damaged. Easy to age. The manufacturing and installation costs are very low. In areas with high and low temperatures, the service life is shorter. People with heavy weight should pay more attention to safety. The advantage of plastic ring is that the shape and color of spokes are changeable, the cost is low and the installation is fast. Don't repair it, throw it away if it breaks down and replace it as a whole.

Wheels, tires and bicycles of unicycles are completely universal and can be easily bought locally. Because only one wheel bears the gravity of the human body, the impact force when jumping, and the impact force when the car often falls. The quality and strength requirements of rim tires are higher than those of high-quality bicycles, which are not comparable to those of ordinary bicycles.

1, specifications and dimensions: outer diameter and tire width. The commonly used d * w, such as 20* 1.75, indicates that the tire outer diameter is 20 inches and the tire width is 1.75 inches. People often simply say how many inches (actually wrong 1 inch = 3.33 cm). 1 inch = 2.54 cm. Common specifications of unicycle are 16 inch = 4 10 mm, 18 inch = 460 mm, 20 inch = 5 10 mm, 24 inch = 6 10 mm .. Most off-road unicycles use 2./ The tire width of competitive unicycle is 1.75 inch. Standard rims can be replaced by tires of 1.95, 2.025, 2. 125. Be sure to pay attention to whether the clear width inside the fork can be accommodated, and the gap between the two sides should be above 3 mm

2. Tire pressure: Tire pressure refers to the tire's ability to withstand air pressure. To put it bluntly, it is the bearing capacity of the tire. Motorists weighing more than 95 kg should consider when choosing tires. Most people just need to choose high-quality tires, so don't worry about it.

Tread pattern is also very important, but it has not attracted the attention of ordinary people. It is best to use dome tires for ordinary unicycles. The cross section of the dome tire is circular, with small contact area with the ground, small resistance and flexible turning.

(1) Pingdingshan tire:

In addition to mountain unicycle and obstacle unicycle, it is best not to use Pingdingshan tires, especially flat-topped tires with large teeth on both sides of the tires, which have large contact area with the ground and great resistance, making it difficult for beginners to turn. Tread is easy to wear. It is difficult to turn on soft ground such as soft soil, sand, mud, snow and plastic runway.

Bald tires are concave tires. Except for racing, don't use bald tires, which are easy to slip in slippery, snowy, muddy and grass, and the safety is poor.

4. Colored tires: The main additives in the process of rubber processing and manufacturing tires are sulfur (vulcanization process) and carbon black, so it is black under normal circumstances. In order to gain extra profits, create concepts and attract attention, manufacturers add colored solid pigments to tires. This also indirectly leads to changes in the chemical structure and physical properties of rubber. The person in charge can say that the same manufacturer, the same model of tires, color tires are definitely not as good as black tires. But the price is much higher. When have you ever seen the colored tires of Formula One racing cars and airplanes? But regular manufacturers will consider the product performance, so as not to affect the safety of bicycles and unicycles. The new colored tires look beautiful in many colors, but they are easy to get dirty after use and difficult to clean. Ugly. Besides, who always watches the wheels ride a bike? Again: let nature take its course, don't pursue it deliberately.

5. Inner tube: Butyl inner tube is the best choice for inner tube, with good quality and good air tightness. Generally, it is 1, and it is only pumped once every two months, which is convenient and convenient.

A brand-name high-quality tire: The best tire in China is Chaoyang brand tire. Famous unicycles abroad often use better Taiwan Province Jianda tires, Zhengxin tires and Zheng Xin high-end Maxxis tires.

Inferior tires: Inferior inner and outer tires refer to fake and inferior tires and refurbished tires processed and manufactured by some small enterprises, most of which are small workshops. The wholesale price of a set of inner and outer tires is less than 10 yuan. The production equipment and technology are extremely simple, and the quality of employees is high. The raw materials are recycled rubber and chemical waste. The difference in quality is beyond your imagination. Toxic and harmful, it gives off an unpleasant smell indoors, which is very harmful to people's health. Inferior tires have no quality, uneven thickness, different thickness, rough surface and uneven surface. Short life, easy to leak, wear, crack, bulge and even puncture. It is extremely detrimental to safety, especially for children and adolescents. Safety accidents caused by tires are not uncommon, so parents should not take any chances. You will regret it after the accident. Just bought or used soon, the tire leaks, which is inferior.

1, the technical index of the virtual standard, is beyond the reach of the sky, so the tire pressure of inferior tires is not credible, even the tire width that experts can see dares to be virtual standard, such as marking 20* 1.75 as 20* 1.95 and so on. )

2. Do whatever you want, seize the layman of consumers, advocate high-end hearts such as mountain bikes, and make the tire shape into mountain bike tires and off-road tires.

3, concept hype, expired customers. The most typical is to make colored tires (inferior colored tires are commonly known as foam tires). Have you found that inferior unicycles costing more than 100 yuan and inferior bicycles above 200 yuan abound? Colored tires are the worst among inferior tires.

Nowadays, high-quality tires are very cheap relative to people's income, and the use cost is not more expensive than inferior tires. Security is different. Why not?

The seat of a unicycle is special in the field of transportation, because its shape and function are similar to those of a seat, so it is called a seat. Bicycles are called car seats, cushions and seat bags.

Saddle consists of: front armrest, rear armrest (rear trailer) bottom plate (seat plate), cushion, reinforced steel plate, seat cover and mounting screw gasket.

Saddle supports most of the weight of human body, so the shape of saddle must match the shape of human leg, increase the contact area with human body as much as possible and reduce the pressure on human body. The surface of the seat should be soft and comfortable, breathable and sweat-wicking. Improve ride comfort.

Saddles have to bear the huge impact force when the car falls and the friction force between the saddle and the ground when mopping the floor, so the strength and durability of the saddle are very high.

The car seat is also a handlebar. To carry, to push, to ride, to do all kinds of technical movements. Therefore, the shape of saddle, especially the shape, strength and service life of front armrest and rear trailer, is particularly important, especially the shape of front armrest must conform to ergonomics and be easy for people to grasp. The scientific shape of the front armrest is duckbill (which looks like the head and mouth shape of an eagle and a bird in side view), as shown in the figure below, extending to the front and bottom of the saddle. A good front armrest also has a horizontal opening, which is conducive to grasping and breathable perspiration.

1. Front and rear handrails and floor: generally made of PVC film resin, with light weight, good elasticity, high strength, long service life and comfortable grip. The more advanced bottom plate is forged from aluminum alloy plate. Inferior handrails and seat boards are made of recycled plastics and chemical waste. It's easy to break, and sometimes it hurts people. Harmful substances endanger human health.

!

2. A good cushion is mostly heavy sponge or polyurethane formed by one-time foaming. Good elasticity, soft and comfortable, not easy to collapse and deform. The inferior cushion is mostly light sponge or foam, and it is mostly packaged by recycled products.

3. Seat surface. Most of them are sewn with high-grade PU leather, which is fine in workmanship, smooth and wrinkle-free. Leather is extremely rare and expensive. The inferior seat surface is mostly made of inferior artificial leather, which is rough and disorderly, with uneven stitches and jumpers and threads everywhere. The seat surface is easy to crack. Life is short.

4. Reinforced steel plate: galvanized or nickel-plated sheet is generally used. Good reinforced steel plates have high strength and elasticity, while inferior steel plates are prone to rust and fracture. Saddles with aluminum base plates have no reinforced steel plates.

When it comes to saddles, we cannot but mention the toxicity of plastics and dyes to human health.

The harm of unicycle to human body mainly comes from pedal plastic, paint, tires and car seats. Among them, pedals, paint and tires mainly pollute indoor air and indirectly poison human body. When riding outside, the harm caused by air circulation is not particularly great. Paint and saddle are in direct contact with human body, and the harm is inevitable.

Sources of toxic substances:

1. Many recycled plastics used for inferior saddles come from abandoned pesticide sprayers and chemical raw material packaging barrels, which are very toxic.

2. Inferior car seat In order to reduce the cost, recycled plastics, seat surface materials and dyes all contain heavy metal ions such as mercury, cadmium, lead and hexavalent chromium. After entering the human body through hand and skin contact, the protein of human cells deteriorates, leading to pathological changes. It is more harmful to children and pregnant women.

3. Azo dyes are used in plastics, seat surfaces and cushions of inferior car seats. Azo dye (an organic compound with aryl groups at both ends of azo group) is the most widely used synthetic dye for coloring textiles, leather, paint, plastics and rubber. Under special conditions, it can decompose and produce more than 20 kinds of carcinogenic aromatic amines, which can change the DNA structure of human body through activation, cause diseases and induce cancer. In view of this, in 1994, the German government officially banned the use of certain azo dyes in consumer goods that have been in contact with the skin for a long time, and after the implementation of 1996 in April, the Dutch government also enacted similar legislation in 1996 in August, and France and Australia were also drafting similar legislation. In 2002, the General Administration of Quality Supervision, Inspection and Quarantine of China drafted. But the laws of our country exist in name only. Have you noticed that all regular large milk powder manufacturers dare to add melamine to milk powder? What are the fears of unicycle manufacturers in small workshops?

Azo dye incidents occur frequently in China, and toxic clothes, towels, diapers, toys and other common newspapers. The most famous ones are Sudan red poisonous eggs and poisonous duck eggs, which sensationalized the whole country the year before last. Sudan red is the most common azo dye.

The inferior saddle does not conform to the human body shape. People are extremely uncomfortable when riding, and often oppress individual parts, resulting in poor blood circulation. In particular, toxic substances can cause itching in the crotch, even redness and herpes. Some saddle shapes can also cause accidental injuries to male riders. Broken handrails of inferior car seats often scratch hands and legs. The sudden break of the car seat caused people to fall off the car and get injured. We must attach great importance to it.

Supplementary explanation:

Most colored tires use azo dyes, and most colored tires produced by regular tire rubber factories are colored-edged tires. In order to ensure tire strength and prevent azo detection from exceeding the standard, large regular manufacturers do not produce tires with colored treads. The worse the tire, the brighter the color.

In life, people often ignore the harm of toxic substances to people. In order to save a few dollars, they often buy inferior and harmful products, thinking that they have picked up a big bargain. The cost of future health damage is thousands. Pie falling from the sky is either a trap or a trap. Shopping wins manufacturers, and the stock market captures Zhuang. It's all human fantasy! People can't live without dreams, but they can't be paranoid. Be sure to know more about product knowledge, choose regular products and honest sellers to prevent being cheated.

Little experience: the saddle must be covered with a seat cover. Without a seat cover, the seat surface and pants are easy to get dirty, especially after sweating. In summer, when the sun comes out, it will burn people. It is very cold in winter. The seat can be made of silk weaving or cloth. It is best to expose the front armrest and thicken it before dragging it.

end

Are you satisfied with the above answers?