Unlike a schrader the system doesn t use a check valve it seals entirely based on pressure in the tube or tire.
Bicycle tube valve stem types.
The valve stem opens by unscrewing a knurled textured nut at the top.
Now that said it is extremely difficult to get any parts of a high quality in some parts of the world anyway.
A third rarer type of valve is the woods or dunlop style.
Bicycle inner tubes have two major types of valves.
Learn the difference between presta and schrader valve stems on bicycle tubes and how to use different pumps to inflate them.
Finally keep an eye on the valve length.
Valve length and valve extenders.
If you ve got deep section wheels you ll need bike inner tubes with longer valves to make sure that they protrude.