If you’re new to the road biking world, be warned, it’s more than likely that the first time you go to air up your tires, you’re going to be surprised at what you find. The valve your road bike is likely unlike any other you’ve used, especially if you only have your car to compare it to. Your road bike has what is referred to as a “Presta valve.”
So, do all road bikes have Presta valves? Yes. Well, mostly, yes. The majority of the road bikes that are in motion today do have a Presta valve. Presta valves are the most common in road bikes.
There are a few reasons why Presta valves are used for road bikes – and we are here to share those reasons with you.
What are Presta Valves?
Before we dive into Presta valves and their use in road bikes, let’s discuss what a Presta valve actually is. The valve on your tire is the little peg-like metal piece that is located on a tire. Its main purpose is to take air from another source and funnel it into the tube of the tire.
Presta valves are also known as “French Valves” or even “Sclaverland valves.” They don’t look like the valves that we use to fill up our car tires. Those are called Schrader valves. There is usually a cap on the Presta valve, just like there’s a cap on Schrader valves, but this isn’t necessary to the function of the Presta valve itself.
If the cap comes off of a Presta valve, the tire will not lose air. The air is kept inside of the Presta valve by other air. When the valve is filled, the air pressure keeps the internal lock nut lifted to prevent air from leaking out.
Presta Valves are made completely of metal. They are longer and skinnier than the Schrader valves. They also have a thinner piece of metal at the top, kind of resembling a flat top screw. The threads on this piece allow the lock nut to move up and down. Again, the lock nut is what’s unscrewed when filling up a tire with a Presta valve, and allows the air to flow in.
How are Presta Valves Different from Schrader Valves?
We mentioned a couple of differences briefly, one of the main ones being that Schrader valves are the ones that are used in car tires. To understand a little more of how Presta valves work, let’s briefly go over the differences between these and the Schrader valves we’re used to.
This will help get a better overall picture of what we’re working with, in terms of road bikes. And, if anyone’s wondering, no, the two are not interchangeable. While it might be easier to switch a Presta valve to a Schrader valve, just for convenience purposes, it won’t work.
Lock Nut vs. Spring
Like we mentioned, a Presta valve has a lock nut that must be loosened in order to accept air. There is a lid on the Presta valve, but it’s to protect against anything getting into the valve and tire, not to keep air from getting out.
Schrader valves have an internal spring that has to be pushed to allow air in or out. It’s important to note that you should always make sure the lock nut is tightened; otherwise, it will jiggle around as you ride.
Size and Appearance
This is the main source for identifying the difference between the two. A Presta valve is, again, the tall skinny one of the two. A Schrader valve is a bit shorter, and thicker in diameter. And, of course, a Schrader valve is usually capped off by a lid.
This is why the two aren’t interchangeable. If a bike is fitted with a hole for a Schrader valve, it’s a wider hole. And, a Schrader valve won’t fit into the smaller sized hole in a rim that fits a Presta valve.
Inner Tube Sizing
Although you’d never know unless you took the tubes out, it’s worth noting because this helps with the overall picture we’re going for. Presta valves work with thinner inner tubes inside of the tire. And, on the other side of things, Schrader valves are used with thicker inner tubes.
But What Exactly is a Road Bike?
Road bikes are exactly what the name suggests. These bikes are meant for riding on solid surfaces, such as roads. Road bikes are also sometimes referred to as “racers” since they’re used in bike racing.
If you see someone in their full cycling gear, they’re most likely riding a road bike. Road bikes are designed to go fast, so they have an aerodynamic design. Even the seat and handlebars are positioned just right, so the rider becomes aerodynamic as well.
There are just a few things that make a road bike stand out against other types of bicycles. Here are just a few of those identifying features.
There’s a little variance here, depending on the riders’ preference and what makes him or her most comfortable. But, in general, the handlebars on a road bike are curved under, resembling almost a ram’s horn. Sorry, that was the first thing that popped into my mind, but it’s also pretty accurate. They also sit a little lower on the bike frame.
On a road bike, you’ll notice that the tires are much thinner than other types of bikes, like a mountain bike. Road biking is hopefully a bit of a smoother ride (hopefully, unless you encounter some unexpected terrain or you live where I do, and they don’t fix the roads), so thicker tires aren’t necessary. The size of the tires is also consistent with the fact that road bikes are also used for racing.
Why are Presta Valves Used with Road Bikes?
Now that you’ve got all the facts, we can get right into why exactly Presta valves are used on almost every single road bike.
As we just discussed, road bikes have thin tires. And, Presta valves are thinner. This is no coincidence. A valve directly affects the integrity of the rim on a tire. The valve creates a bit of a weak spot where it’s installed on the tire.
Therefore, a more slender Presta valve will impact the tires’ rim less than the thicker Schrader valve. So, the thin road tires and Presta valves are a great match.
Easy to Inflate
Although you have to turn the lock nut, that’s just about the hardest part. The rest is super simple, which is what makes it ideal for bike racing. If time is of the essence, stopping to deal with a bulky hose.
Instead, a Presta valve simply requires the rider to attach the pump and fill it up. And, if necessary, there are adapters that can screw onto the top of the Presta valve to be used with a Schrader pump.
Holds More Pressure
Presta valves are able to hold higher pressure than Schrader valves. This makes the tires perform better, in terms of distance of riding and speed. A tire that has more air in it can ride over smooth surfaces faster, like roads.
Presta valves are also offered in different lengths:
- 34 mm
- 48 mm
- 60 mm
Different brands of road bikes will use different lengths of Presta valves. The length of the Presta valve is dependent on the size of the road bikes’ rim. But some riders will adjust the length of the Presta valve based on how they’re able to grip the valve while filling the tire with air, or even for aesthetic reasons.