Shrader vs. Presta
Valves, why are there different kinds?
The story is pretty common. Someone gets into Mountain biking, Road bikes, or cross-overs, and discovers there’s a whole world of technology that they weren’t aware existed. Occasionally, this happens when someone discovers their buddy’s tire pump and it simply doesn’t fit. It’s either too big, or too small, and that’s the moment that they discover the difference in valve types. Other times, someone notices that a pal’s bike has valve stems that look different than the one’s that are on their bikes. Welcome to the world of Schrader and Presta Valves.
Let’s start with an explanation of why the valves look different, and what the differences are. Then why Presta valves are commonly found on more expensive bikes, and what the value addition is. We’ll top off the valve conversation with some basic tips and maintenance suggestions, and finish with air pump types that you should be aware of (especially if you own different bikes with BOTH types of valves!)
Why do Schrader Valves and Presta valves look different from each other?
Schrader valves are the valve stem that is most common. You’ll find them on vehicle tires, bike tires, ATVs, trailer tires, and pretty much everywhere you can add something in front of the word “tire.” Schrader valves came first. Most often, the valve stem will have a rubber wrapping around it, with just the top outer wall threaded to accept a cap. If you look inside the valve stem, you’ll find a pin in the center is spring-loaded. There is a check-valve there that controls the airflow in and out. If you press down on the spring, with your fingernail, you’ll hear the hiss of air releasing (when inflated). Schrader valves require pressure on this pin to open the check valve and allow air to enter the valve stem. A cap is commonly used, because an accidental depression of the pin will result in deflating the tire. They’re prone to collecting dirt and clogging, too, if you’re not careful with caps. Additionally, the core can be removed by unscrewing the internal bits. A slotted tool is used to allow you to put pressure on both sides of the check valve and unscrew it. You’ll need to do this if you ever choose to add sealant to your tire. Sometimes, the valve cores have to be replaced, too, if they get damaged. We recommend keeping the caps on, for this reason. You’ve probably used Schrader valves your whole life, on your first bikes, motorcycles, cars, etc. They’re very common.
Presta valves are only about half as wide as a Schrader valve, though they’re usually about the same height. The smaller diameter even slightly tapers toward the top, and some valve stems are threaded all the way down. Unlike the Schrader valves, the valve stem opens to air, by unscrewing a textured not on the top of the stem. This texturing is called “knurled” if you want to use the correct term. There’s no pin here and check valve system. The seal is entirely based on the pressure of the tube or tire. Most Presta valves (even on tubeless tires) have a fully removeable core. This means you need to be careful when removing the top stem nut. If you accidentally unscrew the whole thing, you’ll discover very quickly that the core is holding the air pressure in!
Why are Presta valves found on high performance bikes?
Unlike Schrader valves, which are found on many different tire types, Presta valves were literally designed for bikes. There are four primary reasons they’re found on high-end, or high performance bikes.
They are thinner to allow for a smaller hole through the rim (which, in turn, increases rim strength)
They are unlikely to ever clog (as there is no check valve system)
They are lighter (while only a small difference, this counts when you’re using high-performance wheels that need counterbalancing in order to spin smoothly)
They’re quite easily extended (which matters a LOT when you’re using aerodynamic rims found on higher performance bikes).
Basic tips and maintenance
As mentioned, when using Schrader valves, it’s always a good idea to cap them. This prevents debris and material from clogging the check valve. It’s also a good idea to make sure whatever you’re attaching to your Schrader valve is ALSO clear of debris. It doesn’t do you a lot of good to keep a cap on, and then lift an air pressure fitting from a mud puddle to attach to your tire.
It’s definitely NOT a good idea to mix and match valves with rims. Because the rims are drilled for the specific type of valve (Schrader or Presta), you should use the type that your rim is designed for. If you put Presta valves in a Schrader cut rim, you’re likely to have some movement around the valve stem, due to the larger opening. This can even cut your tube. Schrader valves don’t even FIT in a Presta fitted rim unless you were to cut a larger hole. This is bad for the engineering and rim strength. Get the right kind of tire tube with the correct valve.
Air Pump Types
It used to be, that you had to buy a pump that either had a Schrader fitting, or a Presta fitting. While this is still the situation with most air pumps (designed for one or the other), many modern bicycle pumps now have either a swapable head (found on many frame pumps and mini-pumps), or an adjustable head, which actually fits on either valve type. It’s important to know which type of air pump you have. You may end up upgrading a bicycle, and have Presta Valves, and when you need an air pump the most… you discover you didn’t upgrade your pump as well!
The quick summary, is that both valve types are quick common, though Presta are found on many higher-end bicycles for the value-additions noted. Definitely make sure you have the right pump when you go out, and enjoy the ride! Visit us online @ ridgelinebikenski.com or give us a call for anything you may need!