The Dunlop valve, (also called a Woods valve or an English valve) is a type of pneumatic
valve stem
A valve stem is a self-contained valve which 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, or both, to prevent the gas from escaping ...
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 lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreem ...
. The Dunlop valve has a wider base than a
Presta valve
The Presta valve (also French valve (FV) or Sclaverand valve) is a tire valve commonly found in high pressure road style and some mountain bicycle inner tubes. It comprises an outer valve stem and an inner valve body. A lock nut to secure the ...
, similar enough in size to a
Schrader valve
The Schrader valve (also called American valve) is a type of pneumatic tire valve used on virtually every motor vehicle in the world today. The Schrader company, for which it was named, was founded in 1844 by August Schrader. The original Schra ...
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 It superseded Dunlop's original valve for pneumatic tyres.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 USA, where either
Presta or
Schrader valves are used.
Dimensions
External thread: x 32
TPI (
pitch)
See also
*
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 d ...
*
Bicycle tire
A bicycle tire is a tire that fits on the wheel of a bicycle or similar vehicle. These tires may also be used on tricycles, wheelchairs, and handcycles, frequently for racing. Bicycle tires provide an important source of suspension, generate ...
*
Inner tube
An inner tube is an inflatable ring that forms the interior of some pneumatic tires. The tube is inflated with a valve stem, and fits inside of the casing of the tire. The inflated inner tube provides structural support and suspension, while the ...
References
External links
Valve threads
Bicycle parts
Air valves
{{Cycling-stub