For the small size, the valve plays an important role in ensuring a fun bike ride. And besides that, there is a lot to know about a valve to be able to use it properly. You’re going to find a Presta valve on most bikes these days, but the Schrader valve used on car tires also comes along. And what about the Dunlop valve?
Why are the two valves used interchangeably and what are the differences? Here’s everything you need to know about something as futile as a valve.
What type of valves are there?
Bicycles usually come with one out of three types of valves:
- Schrader: Even though it’s wider than a Presta valve. It usually has the same circumference over the entire length. Often wrapped with rubber. The outer wall is threaded to tighten a valve cap or the head of a pump. The pin in the middle is a non-return valve that regulates the airflow in and out of the tire using a spring. Check valves are designed to allow airflow in one direction only; the Schrader valve requires pressure on this inner pin to allow air in.
- Presta: about half the width of a Schrader valve and made entirely out of metal. They run slightly tapered upwards and some have threads down. The valve opens by unscrewing a toothed nut at the top. Unlike a Schrader valve, the Presta does not have a check valve – it closes completely based on pressure in the inner tube or tubeless strap. Many Presta valves, including those for use in tubeless tires, allow you to remove the entire core of the valve. Be careful when unscrewing the knurled nut so that you do not accidentally unscrew the whole core. This will allow all the air to come out of the tire at once.
- Dunlop: We often see the Dunlop valve on city bikes. They look a bit like a thick Presta valve. On sporty bikes you never really see them.
Where are they on my bike?
On your tires, of course. Particularly on the inside of the rim. But you can also find Schrader valves on dampers: those of a suspension fork or rear silencer of a full-suspension mountain bike.
Why do most bikes have Presta valves?
Presta valves were invented by the same man who later founded Zéfal, one of the leading manufacturers of bicycle pumps. Compared to Schrader valves, Presta valves are ideal for bicycle tires for many reasons:
- They require a smaller hole in the rim, which increases rim strength.
- They are lighter, so the wheel can rotate extra smoothly.
- They seal tightly with air pressure only, so there is no need for a mechanical check valve like the Schrader system (which can get clogged with dirt).
- They are easy to extend with adapters, making them ideal for high aerodynamic rims.
Are they interchangeable?
You can place a Presta valve in a rim made for a Schrader valve, but only as an emergency solution. Your inner tube and outer tube tend to move slightly over the rim. In the wider Schrader hole, a Presta valve can move a lot, so the edge of the rim will eventually damage the valve at the point where it turns into the tire. If you need to put a Presta tire in a Schrader rim to get home, use the small nut to tighten it against the rim.
The only way to fit a Schrader tire in a Presta suitable rim is to widen the valve hole. Something we do not recommend, as this could endanger the quality of the rim.
Which pump should I use?
A Presta pump has a rubber gasket in the head or claw that fits well around a Presta valve, but not around a Schrader valve. A Schrader pump has a pin in the center of the pump head to press the non-return valve of the Schrader valve. If you try to place it on a Presta valve, it simply won’t fit.
Many modern pumps have a two-head design.
These come in three types:
- Double head: found on many floor pumps. The head of the pump has two separate couplings for a Presta and Schrader valve.
- Interchangeable head: found on some mini-pumps. This head has a gasket with a cone-shaped hole. One side is narrower, for Presta valves. Unscrew the cap, turn the gasket the other way around, screw the cap back on and you have a pump for a Schrader valve.
- Adjustable head: the newest kind. This head fits Presta and Schrader valves without changing internal parts. Just press the head firmly on the valve, turn the lever to lock the pump, and start pumping.
Do I ever need to replace a valve?
Most valves are attached to the tire, so if you want to replace it, you’ll need to replace the whole tire. However, two scenarios require valve replacement:
- Tubeless: Presta valves for tubeless tires are sealed by a nut that attaches the valve to the rim. If that seal no longer works properly and your tire loses air, you can simply replace the valve. Some tubeless valves are wheel or rim specific; make sure you have the correct valve, otherwise, the seal may not seal properly.
- Replaceable cores: some Presta’s have cores that can be unscrewed – important if you want to be able to extend the valves for high rims or if you want to add tire sealant. If your tire doesn’t hold air or if the sealant has dried inside the tire, you can easily replace this core with a new one. Most bicycle stores have replacement cores. You can see if a valve has replaceable cores if the sides have small, flat parts, exactly at the point where the valve tapers upwards.
Tip: use a USB rechargeable electric pump
If you use a USB rechargeable electric bike pump, you don’t need power. Nowadays, these rechargeable mini-compressors are so small that you can take them with you on the road.
Of course, you can use an electric bike pump on any type of bike, not just E-bikes. This type of device is multifunctional and you can use it for your bike, motorcycle, car, or to inflate sports balls.