Although the Presta and Schrader valves are the most used, there is a third (Woods or Dunlop valve) that is used in some Asian and European bicycle models. You can see both on these best mountain bikes under 500. In this article, you will find the main characteristics of each of them, their advantages, disadvantages and the most common uses.
Presta vs Schrader valve: Main differences
Presta valve
The Presta, or “French” valve, was expressly designed for use on bicycles. It has a smaller diameter in relation to the Schrader and Woods valves. This feature requires a smaller hole in the rim (7mm diameter), making it a better alternative for narrow wheels.
Its body is made entirely of metal and is generally fully threaded. It has a metal stem or pivot in the center, responsible for allowing air flow. The pivot is opened and closed by means of a crown or cylindrical nut in its upper part. This type of valve can be found in different lengths (40, 60, 80 mm) to use, depending on the profile of your ring.
To inflate a tire with a Presta valve, it is necessary to open the valve by turning the crown counterclockwise. At the end of the inflation process, it must be closed to prevent air from escaping.
This type of valve requires a special nozzle to inflate. If you do not have the necessary nozzle in your pump or inflator, you will require an adapter that allows you to inflate with an air pump or even in car service stations.
Presta to Schrader adapters
Today, most bike air pumps allow you to inflate Presta valve tires with no hassle, either through interchangeable nozzles, universal nozzles, or dual heads.
Advantages of Presta valves
- Facilitates inflation at high pressures
- They tend to have less pressure loss
- Weighs less than other types of valve
- Requires a smaller diameter hole, which improves the resistance of the rim
- Ideal for aerodynamic profile rims
Disadvantages of Presta valves
- It requires a special nozzle for inflation. However, any bicycle air pump already has it.
- Fragile pivot (howitzer or stem) that can bend or break if not used correctly.
Common uses
Presta-type valves are common on mid to high-end bikes. Because they are narrower and lighter than the Schrader and Woods valves, it is not uncommon to find them on the road, track and other bikes with narrow rims. This type of valve is also the most common on tubeless rims.
Schrader valve
Your first bike was probably equipped with a Schrader valve, also known as an “American” valve. This type of valve is wider than the Presta and with a uniform circumference throughout its entire body. The rings designed for this type of valve usually have a hole between 8.5 and 9 mm in diameter.
As in the previous case, its body is metallic and threaded. Oftentimes, the valve is rubber-lined, leaving enough thread uncovered to be able to put a cap on and hold the air pump nozzle. However, you can also find Schrader valves that lack rubber coating. It is possible to inflate these types of valves with the same pump that you use for a car tire, so it will be easy for you to inflate it even at gas stations.
Unlike the Presta, the Schrader works like a check valve. That is, it only allows air flow in one direction. The pivot or stem has a spring that keeps it in the closed position and opens with the flow of air from the inflator.
The nozzles used to inflate these types of valves have a structure in the center that pushes the pivot to allow air to enter. If you want to get air out of your tire, just press the valve pivot with a screwdriver or some other pointed tool that allows you to press the stem or pivot.
Advantages of Schrader valves
- Easy to inflate with almost any air pump
- You do not need extra accessories for inflation
- They are cheap
Disadvantages of Schrader valves
- Limited ring compatibility
- They tend to have greater air pressure loss
- Although not a general rule, it is possible for the valve body to decapitate from the chamber body
- Its body is shorter, so it can sag during inflation
Common uses
Manufacturers generally install this type of valve in their low and mid-range models, as they are suitable for wide rings. There is a myth that Schrader valves are not suitable for high pressure. However, pneumatic telescopic seat posts and suspensions use this type of valve, with pressures between 200 and 300 PSI.
Woods valve
The use of the Woods valves, also known as Dunlop or “English” valves, is not as popular as the earlier types. They are currently used in certain models of bicycles in some Asian and European countries.
Its body thickness is very similar to that of the Schrader valve but with a narrow tip more similar to the French valve. Their average diameter is 7.7 mm, which allows them to be used in hoops with larger holes. To inflate a Woods valve, you will need the same nozzle as for Presta or alternatively, you can use an adapter.
Its internal pivot has a rubber seal or a small latex sleeve that prevents air from escaping. As you pump, the air pressure expands the seal and enters the chamber.
The seal or small latex sleeve may be damaged, which is why some patch kits include this type of replacement. Alternatively, the entire pivot can be replaced with ease.
Advantages of Dunlop valves
- Less pressure loss
- Easy to disassemble
- Simple removal of the pivot or stem
Disadvantages of Dunlop valves
- Found on old or rare bicycles
- If the latex that covers the inner part of the stem deteriorates, it will not work
- Less common in the market
Common uses
It is generally found in urban-type bicycles of Asian manufacture and also in some European ones. It can also be found on some old bikes.
Compatibility between valve type and bicycle rim
Since the rings have outlet holes according to the type of valve for which they have been designed, the compatibility between the different types of valves has certain limitations.
For example, you will not be able to mount a Schrader valve tube on a Presta valve rim because it will not fit. However, in an emergency, you can still use a Presta valve tube on a Schrader valve wheel. In keeping with the above, a Presta bore rim can probably be used with a Woods valve tube, as long as its profile is low.
If you use tubeless rims, it is very important that the valve is the correct one for the rim you will be using. Although Presta valves are more common, it is possible to find Schrader-type tubeless kits.
The right pump for the valve type
As we have already mentioned, the vast majority of bicycle air pumps allow you to inflate any type of valve. In the simplest pumps, it is necessary to open the head and invert a small cylinder inside. Other more advanced pumps include dual heads, like the one shown in the image above, or have universal nozzles, which adapt to all types of valves.
In some portable pumps, there is another variant in which it is enough to place the hose in one direction or the other depending on the type of valve.
Conclusion
In short, we cannot say that one type of valve is better than another. The selection should be based on your needs, type of rim and rim that your bicycle uses.
For example, for someone who rides a bike in the city, whose tires do not require more than 50 PSI and low profile rims, the most practical may be the use of a Schrader valve. In this case, you have the benefit of being able to inflate your tires at any service station or gas station. Be careful. The issue of pressure is not a limitation of the type of valve. Rather gas station compressors do not have the ability to inflate a tire that requires 100 PSI.
With the above in mind, if your tires require high pressures (from 80 to 100 PSI, for example) and also your rims are narrow or with a high profile, the Presta valve may be a better option. In this case, it is best to inflate with a pump capable of generating the right pressure for your tires.
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