Presta and Schrader’s valves are the two major types of bike valves. They are totally different from each other and you as a cyclist should know which one your bike has.
Presta valves are found on most road bikes. Most tubular and inner tubes on road bikes use Presta valves. It is slim, light and has a locking nut for opening and closing on top.
It is made up of an outer valve stem and an inner valve body. A locking nut to guide the stem at the wheel rim and a valve cap may also be included. It is also known as the French valve or the Scaverland valve.
Schrader valves are mostly used by mountain bikes, cars, and other vehicles. Schrader valves are robust, large and contain a spring mechanism inside to keep the valve closed ( Rather than the locking nut used by Presta valves). The Schrader valve is universal and used for almost every kind of automobiles.
DIFFERENCES BETWEEN PRESTA AND SCHRADER VALVES
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1) Schrader valves are thicker, and can hardly fit through the tube of a road rim. In narrow road tires space might not be enough for the Schrader valve to fit in.
Presta valves will also need electrical tape, shims, or adapters to fit on a mountain bike rim because they are narrower in contrast to Schrader valves.
2) Presta valves are easier to pump with little effort required. they can be inflated with small capacity hand pumps due to the fact that there is no spring in the valve. Schrader valves are relatively more difficult to pump and it requires a pump with a mechanism to deflate the spring in the Schrader valve.
3. The two valves require different types of pump heads which imply that a Schrader headed pump cannot inflate a Presta tube valve and vice versa.
There is a solution to this as pump head with dual attachments have been invented. This type of pump features both heads, therefore, you can use either of the pump head designed for your valve.
4. Schrader Valves tube valves are wide and flat in the end. While Presta Valves tube valves are narrower and have a locking nut at the top. The locking nut can be loosened to add or release air. releasing the air is quite easy, it is done by loosening the locking nut then pressing to let the air out.
PUMPS TO USE
There are different types of pumps and using a Schrader pump for a Presta valve will not work out, which is the reason why it is necessary to confirm the type of valve your bike uses in order to get the correct bike pump.
You can get a pump with dual head attachments that work for both valves. Dual head pumps can be in the form of twin head, adjustable head, or swappable head.
Types of Dual Head Pumps
1. Swappable head: This is found on some floor and portable pumps. The head has a gasket with a conical hole. The narrower side being for Presta. All you need to do is to open the chunk cap and flip it to the side that fits your valve and screw back the cap
2. Twin head: This is usually found on floor pumps. It has two separate gaskets for Presta and Schrader valves. Simply use the one that matches your valve.
3. Adjustable head: It is the latest style of dual-head pump. It fits into both types of valves without adjusting or changing any of the internal parts. All you have to do is press the head firmly to the valve, flip the lever to secure then you start pumping.
REPLACING A VALVE
Most valves are attached to the tubes so in most cases you will have to change the tube. However, you can replace valves in cases where you have;
1. Replaceable Cores: Some Presta valves have the replaceable core that unscrews the key for adding tire sealant or adding valve extenders to the aero rim. Replaceable cores are available for sale at almost every local bike shop. Your valve has replaceable cores if it’s sides have small, flat sections right as the valve tapers toward the top nut.
2. Presta Valves: Presta valves for tubeless tires are sealed by a knurled nut that fixes the valve to the rim. If the seal happens to fail and is letting air out of your tire, the valve can just be replaced. Some tubeless valves have a specific rim model. Make sure you get the correct replacement, or the gasket might not seal properly.
Because the rims of bicycles drilled for Presta valves cannot contain the wider Schrader valves, drilling the rim is usually necessary for such replacements to be made, which can weaken the rim in a way.
On the other hand, when a Presta valve is fitted into the bigger Schrader rim hole, reducers or grommets are used to fill up the excess space sometimes. An adapter can be used to fit the thread to allow Presta valves to connect to a pump with Schrader chuck.
SWITCHING VALVES
The major difference between Presta and Schrader valves is the diameter. While Schrader valves are larger, Presta valves are rather slimmer and consequently, the valve holes on bicycle rims are drilled to suit a particular size or another.
The major concern with using a Presta valve in a rim drilled for a Shrader valve is not a necessary movement of the valve stem, but rather a hernia of the tube through the excess space at high pressure, causing a blowout.
Most mountain bike tires maintain a low pressure, therefore you might get away with it, however, there is an adapter, also know as a ‘valve grommet’, which is made out of rubber or metal and helps to make the valve hole small enough for a Presta valve to fit tightly. It will also remain tight when under high pressure.