Dunlop valve

{{short description|Bicycle tube valve}}

{{More citations needed|date=September 2010}}

{{Use dmy dates|date=October 2018}}

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The Dunlop valve, (abbreviated as DV; also called a Woods valve, an English valve or a Blitz valve{{cite web

|url = https://www.dutchperfect.eu/assortiment/binnenbanden/12-12x175-blitz-no-flat-los-2.aspx

|title = 12 1/2X1.75 Blitz No Flat Los

|quote = Blitz ventiel

}}) is a type of pneumatic valve stem in use—mostly on inner tubes of bicycles—in many countries, including Japan,{{cite web|url=http://www.japancycling.org/v2/info/bikesj/tyres.shtml|title=Japan Cycling Navigator:Information: Bikes in Japan: Tyres and Tubes|publisher=www.japancycling.org|access-date=1 June 2009}} Korea, India, Pakistan, Sri Lanka, most European countries, and a number of developing countries. The Dunlop valve has a wider base than a Presta valve, similar enough in size to a Schrader valve to use identically drilled valve holes in rims,{{cite web|url=http://guides.wiggle.co.uk/inner-tube-buying-guide/|title=Inner tube buying guide|date=8 October 2018|access-date=10 October 2018}} but it can be inflated with a Presta valve adapter.{{cite web| url = http://www.sheldonbrown.com/gloss_w.html#woods| title = Glossary: Woods Valve| author = Sheldon Brown| access-date = 1 December 2010}} 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 It superseded Dunlop's original valve for pneumatic tyres.{{cite web|last=Moulton|first=Dave|title=John Boyd Dunlop|url=http://davesbikeblog.squarespace.com/blog/2007/8/21/john-boyd-dunlop.html|work=Dave Moulton's Blog|access-date=9 January 2013|date=21 August 2007}}

Dunlop valves are uncommon on bicycles in the US, where either Presta or Schrader valves are used.