The Dunlop valve, (abbreviated as DV; also called a Woods valve, an English valve or a Blitz valve) is a type of pneumatic
valve stem
A valve stem is a self-contained valve that opens to admit gas to a chamber (such as air to inflate a tire), and is then automatically closed and kept sealed by the pressure in the chamber, or a spring (device), spring, or both, to prevent the g ...
in use—mostly on inner tubes of bicycles—in many countries, including Japan, Korea, India, Pakistan, Sri Lanka, most European countries, and a number of
developing countries
A developing country is a sovereign state with a less-developed Secondary sector of the economy, industrial base and a lower Human Development Index (HDI) relative to developed countries. However, this definition is not universally agreed upon. ...
. The Dunlop valve has a wider base than a
Presta valve, similar enough in size to a
Schrader valve
The Schrader valve (also called American valve (AV)) is a type of pneumatic tire valve used on virtually every motor vehicle in the world today. The original Schrader valve design was invented in 1891 and patented in the United States in 1893.G ...
to use identically drilled valve holes in rims, but it can be inflated with a Presta valve adapter. The inner mechanism of the valve can be replaced easily, without the need for special tools.
The Dunlop valve originally used a tight rubber sleeve (see illustration of "original plug") which had to be forced open by air pressure while pumping (not only were these difficult to inflate, but the rubber would perish over time, allowing leakage and eventually, complete failure), but modern Dunlop valves use a different plug (core) using either an internal ball bearing or a spring-loaded rubber plug that is unseated by pumping, making the valve as easy to pump as a Presta valve.
The inventor was C. H. Woods. It superseded
Dunlop's original valve for pneumatic tyres.
Dunlop valves are uncommon on bicycles in the US, where either
Presta or
Schrader valve
The Schrader valve (also called American valve (AV)) is a type of pneumatic tire valve used on virtually every motor vehicle in the world today. The original Schrader valve design was invented in 1891 and patented in the United States in 1893.G ...
s are used.
Dimensions
The external thread of a Dunlop valve is 0.305-32
TPI (approx. 7.75×0.794 mm in
metric designation).
See also
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Dunlop Rubber
Dunlop Ltd. (formerly Dunlop Rubber) was a British multinational company involved in the manufacture of various natural rubber goods. Its business was founded in 1889 by Harvey du Cros and he involved John Boyd Dunlop who had re-invented and ...
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Bicycle tire
A bicycle tire is a tire that fits on the Bicycle wheel, wheel of a bicycle or similar vehicle. These tires may also be used on tricycles, wheelchairs, and handcycles, frequently for Wheelchair racing, racing. Bicycle tires provide an importa ...
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Inner tube
An inner tube is an inflatable torus that forms the interior of some pneumatic tires. The tube is inflated through a valve stem and fits inside the tire casing. The inflated inner tube provides structural support and suspension, while the out ...
References
External links
Valve threads
{{Tires, state=collapsed
Bicycle parts
Air valves