Everything You Never Wanted To Know About Valves

By Brad Quartuccio

Pneumatic tires are what make the bicycle a viable piece of machinery. Without their air cushion and superior traction as compared to solid tires of old, the modern day bicycle would not be as comfortable or as reliable over a wide variety of surfaces as it is today. Invented and first patented in 1846 by Robert W Thomson, the first commercial application was in 1888 by John Dunlop in Dublin when he “discovered” pneumatic tires without prior knowledge of Thomson while searching for a way to smooth the ride of his son’s tricycle. Shortly thereafter I’d imagine some bearded men in short pants began arguing the merits of Presta and Schrader…

There have been a number of valves used on bicycle tires through the years, but save for some places that still use the antiquated Dunlop valve, the majority of bicycles today use either the Schrader or Presta style valve stem. Each ultimately achieves the same thing – keeping air in and allowing easy inflation – and even use similar mechanical poppet valves at their core, but there are some important practical differences between the two.

Schrader valves are far more common on bikes and otherwise, in use for just about every sort of pneumatic valve aside from skinny bicycle racing tires where the Presta style is required due to its slender stem. Width is the defining difference between the two valve stem styles, with the desire for a smaller valve hole and the need for space for the clincher bead to engage on thin road rims being the deciding factor that has kept Presta valves in use. As one would expect from the larger diameter, Schrader valves are the sturdier of the two, rarely breaking off like the Presta style is known to do.

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