A valve stem is an independent valve that opens to receive gas into space (such as air to inflate tires), and then automatically closed and continuously sealed by pressure in space, or spring, or both, to prevent gas escape. They are most commonly used on wheels of cars and bicycles, but also for many other applications.
Video Valve stem
Schrader
The Schrader valve consists of a valve rod in which threaded poppet valve with spring is attached. They are used on almost all tires of cars and motorcycles, and on wider rimmed bike tires. In addition to tires, Schrader valves of various diameters are used in cooling and air conditioning systems, plumbing, fuel engine injectors, suspension systems, and SCUBA regulators, allowing users to remove and install hoses when in use. The Schrader valve on the fuel injector rails of many cars is used as a quick and easy point to check fuel pressure or connect an injector cleaning cartridge.
Maps Valve stem
Presta
The Presta valve (also called the Sclaverand valve or French valve) is usually used only on bicycles. The rod has a narrower diameter (about 6 mm) compared to the thinest Schrader type (nominally 8 mm), and thus the hole hole in the rim passed by the stem can be smaller.
Dunlop (or Woods)
The Dunlop valve, (also called the valve Woods or the British valve) was once popular in England. They are still widely used on bicycle tires in many countries, especially on low to moderate bikes. They can be pumped with a Presta pump.
More
Many other valves are only used in certain areas or for limited purposes.
For example, "Regina Valve" is a valve very similar to Presta and is mostly used in Italy. The tire valves look different in design from traditional tire valves. The inflator rod is not used; instead, a removable cap on the valve rod embedded in the tire rim is installed, with only the lid visible. When inflating the tire, the lid is first removed, usually with a coin, and then a special "portable" inflator rod is screwed into the valve stem. Through the inflator, the tire expands as usual.
References
External links
- summary of the type of bike valve by Sheldon Brown
- common valve type used for bicycles
Source of the article : Wikipedia
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