The tire is the most direct contact part between the bicycle and the ground, which will have a significant impact on the user’s riding style. The importance of a suitable pair of inner tubes for riding is self-evident. Here are some tips for purchasing.
Product category
According to the type of valve, American and French are common on the market, and British ones are basically invisible in the market.
1.British valves
British valves are now rarely used in sports bikes. Because the valve is leak-proof by the rubber sleeve, the leak-proof ability mainly depends on the quality of the rubber tube, and the air tightness is poor and often needs to be inflated. Under high pressure, the edge of the rubber tube of the British valve will leak slightly, and because the rubber tube used is relatively soft, it is easy to age, and it is easy to cause the air pressure cover to crack if it is twisted too tightly. Of course, the price is also lower.
2.American valves
The American valves are mainly locked by internal pressure, which is resistant to high pressure and has a steeper air leakage linearity. That is to say, when the air pressure is not enough, the air leaks faster, the base of the air nozzle is large, and the diameter of the air nozzle is also large, but the inflation flow is large. The air tightness of the American valve is better, and it is much more convenient to pump than the French valve, so it is the most commonly used. Most mountain bikes use American valves, and many low-end road bikes are also equipped with American valves.
3.French valves
The French valve manually locks the valve, which is resistant to high pressure and has a smoother air leakage linearity. The base of the valve is thin and light, the diameter of the valve is small, the impact on the strength of the ring is small, and the air tightness is the best at high pressure. Road tires require high air pressure, so most use French valves. The French valve is very small, and the hole on the rim is also very small, which is beneficial to the strength of the rim. Road cars use more French valves, which may also be related to this.
Shopping points
1.Size specifications
The size of the inner tube should match the outer tire. The sidewall of the outer tire is generally marked with the size, such as 26*1.95 (26 refers to the matching wheel diameter, mountain bikes are generally 26 inches, and 1.95 refers to the section width). Generally, the size of the inner tube has a suitable range. For example, the inner tube marked with 26*1.95-2.1 means that the inner tube can be used with a 26-inch outer tire with a width in the range of 1.95-2.1.
2.Valve length
American valves generally have two lengths, one is 32L (32mm), which is 32 mm in length, which is the case for most mountain bikes. One is 48L (48mm), that is, the length of 48 mm. Some ordinary mountain bikes use thicker rings, so they need to use an extended valve.
French valves are available in 4 lengths, 32mm, 48mm, 60mm, and 80mm.
3.Tube thickness
Tubes of different thicknesses are suitable for different situations. Lightweight inner tubes are mainly used in bicycle speed competitions. Because the thickness is reduced but the strength requirements are not small, the price is more expensive than the ordinary thickness inner tube. Reinforced inner tubes are used for high-intensity use, such as high-intensity mountain off-road, DH, BMX, etc.
4.Tube material
Common materials are natural rubber and butyl rubber. Butyl rubber has better high-temperature resistance and delayed aging than natural rubber, and has a long service life. At the same time, its air tightness is also much better, so the middle and high-end inner tubes are basically made of butyl rubber.
Tips for buying bicycle inner tubes
1.Look.
Observe whether the surface of the inner tube is smooth, whether there are bubbles trachoma, and whether there are cracks in the fold. Generally, the inner tube will be evacuated before leaving the factory, and the damaged inner tube will be passed off here.
2.Smell.
The high-quality rubber inner tube does not smell pungent. If you open the package and smell a strong smell of viscose or asphalt, you should throw it away as soon as possible.
3.Touch.
Check whether the inner tube thickness is uniform. The production of the inner tube is affected by the construction design of the semi-finished product size, the design of the setting ring, the plasticity of the rubber material, the extrusion process, the parking time and parking temperature of the semi-finished product after extrusion, the connection of the semi-finished product head and tail rubber, forming operation, setting operation, mold loading speed, etc. the phenomenon of uneven expansion will occur after the inner tube is inflated. Of course, the above-mentioned influencing factors can be solved by technical means. The higher-end brands have stricter requirements on materials and production processes, and the inner tubes produced are impeccable.
4.Pull.
Pull the inner tube, the high-quality inner tube has good elasticity, can be stretched to several times its length, and there is no obvious deformation after shrinking. After long-term use, the deflation can still return to its original state.
5.Baked.
Place the inner tube in a thermostat at 50°C-60°C for 10 minutes. If the properties of the inner tube do not change, it is a high-quality inner tube. If softening sticking or cracking occurs, it is a poor-quality inner tube.
6.Freeze.
Place the dry inner tube in the freezer or freezer for more than two hours. If the properties of the inner tube do not change, it is a high-quality inner tube. If the inner tube is brittle or cracked, it is a poor-quality inner tube.
