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HOW TO INFLATE PRESTA VALVES CORRECTLY AND QUICKLY
Is your bike equipped with Presta valves, and do you need to top off the air or inflate after changing a tube? We’ll show you which pump to use and the steps to follow.
Most of us only think about our bike tube, its valve, the right pump, and the ideal tire pressure when too little air stops us from riding. And that’s usually the moment we’re in a hurry. Inflating a bike tire isn’t a technical challenge, no matter which valve your tube uses. You just need to know which valve you have, which pump head fits it, and what to watch for, such as the tube material.
What are Schrader, Presta, and Dunlop valves?
Three valve types are found on about 99 percent of all bikes. The Dunlop valve (DV), also called the Woods valve, was the classic bike valve. It consists of a stem about 8 millimeters in diameter with external threads and a much thinner valve core, which is held in the top of the stem by a retaining nut. Few new bikes come with it anymore. In the city and touring segments, Dunlop valves have largely been replaced by Schrader valves, also known as car valves (AV). Their stem is also about 8 millimeters in diameter, but the valve core sits entirely inside the stem, so the pump or its sealing gasket needs a larger diameter. The automotive industry uses the same standard, so you can inflate a Schrader valve on your bike at any gas station without an adapter.
For performance bikes, Presta valves (SV) are now typically used instead of Dunlop valves. Also known as French or road bike valves, they have a thinner stem of only about 6 millimeters and a valve pin that protrudes from the stem. The pin can be secured with a knurled nut. A visibly protruding pin and an airtight seal even at high pressure are characteristic of Presta valves, which are sometimes also called Sclaverand valves.
Presta Bike Tubes from AERON/TPU
City/Tour – UltraProtect
Outstanding puncture protection for touring and daily commuting. Low weight and reduced rolling resistance increase the fun factor on every ride.
MTB – SuperLite Race AL
For mountain bike racers: ultra-light with extra-low rolling resistance. Its extremely compact packing size also makes it the perfect spare inner tube for tubeless riders.
What makes the Presta valve special?
Beyond its looks, a road bike valve differs from other types in a few details of installation and handling. Its thinner stem requires a narrower valve hole in the rim, which in turn benefits the rim’s stability. Unlike the other valves, Presta valves usually come with a rim nut. Threaded onto the valve on the inside of the rim, the nut keeps the valve from slipping too far into the tire while the tire is still uninflated.
The most important feature, though, is the lockable valve pin mentioned above. This central pin opens the valve when pressed or when there is overpressure on the outside. On Presta valves, a thread lets you block the pin’s movement, which the other valve types don’t allow. This means you can screw the valve shut and seal it airtight. The plastic valve cap, by contrast, is purely for dirt protection on every valve type and can’t hold pressure in the tire. Because the pin locks, Presta valves hold air better at high pressure than the others. Depending on the tube model, the valve cores are either permanently attached to the stem or threaded in. In the latter case, they can be replaced or swapped for an extension.
How do you properly inflate a Presta valve?
A bike pump needs two things to inflate a Presta valve. First, the valve opening must be deep enough so that, once the pump gasket has closed around the valve, the now-unlocked valve pin is pushed only into the valve, opening the channel for filling. Second, the sealing gasket at the entrance of the pump head must fit snugly. Pumps for Schrader valves are too wide here, and those for Dunlop valves match the diameter but aren’t deep enough. That’s why many modern hand pumps and floor pumps have two openings: one for Schrader valves and one for Dunlop and Presta valves. Adapters also exist for just about every combination, such as Presta to Schrader, which lets you use a pump at a gas station.
When inflating, a Presta valve differs from the other types in only two steps, both involving the threaded valve pin:
- Remove the valve cap if present. Presta valves don’t need one.
- Rotate the wheel so the valve is at the 6 o’clock position. This lets the pump hose rest on the ground, so its own weight doesn’t bend the pump head, which could bend the valve pin or even tear off the valve.
- Turn the valve pin or the knurled nut on it counterclockwise as far as it goes.
- Press the valve pin briefly into the valve once. If there is still pressure in the tire, this releases some air, clearing dirt from the air channel. It also breaks up any sticking between the pin and the pump head.
- Place the pump head on the valve as straight as possible, using the smaller opening if there are two openings, and close the lever lock right away.
- Pump the tire to the desired pressure while watching the gauge the whole time. The maximum permitted pressure is printed on the tire sidewall. This limit applies to all tube types, including butyl, latex, and modern TPU tubes. The ideal pressure depends on how you ride: lower pressure gives you more grip and comfort, while higher pressure gives you better rolling characteristics.
- Release the lever lock and remove the pump head from the valve as quickly as possible, since some air can escape in this state.
- Screw the knurled nut back into the valve hand-tight. No tools required!
- Put the valve cap back on, if present, and check that the rim nut is secure. It can loosen under higher tire pressure, so tighten it by hand if needed.
What should you do if a Presta valve leaks or becomes bent?
Even though Presta valves are thinner, they aren’t more fragile than other valve types. Only the valve pin can kink or bend if it’s unscrewed a bit from the stem for pumping. Once bent, it often can’t be fully screwed back in and no longer seals reliably. The usual cause is a pump head that isn’t seated straight or that pulls or jerks hard on the valve while pumping.
As mentioned, some tube models have a Presta valve core that can be unscrewed. The tool for this looks like a rounded “A.” If the core can’t be unscrewed and the valve no longer seals, you’ll need to install a new tube.
TIP: When pumping, whether with a hand pump or a floor pump, grip the pump head and the rim together with one hand so the pump moves as little as possible relative to the rim. Always pull the pump head straight off. Never pry it off sideways!
Common Problems and Causes When Inflating Presta Valves
| Symptom | Cause | Solution |
|---|---|---|
| No air goes into the tube even though the valve pin is unlocked. | Valve pin is bent or stuck. | Remove the pump head again and press the valve pin fully into the valve several times, briefly, until you hear a loud hiss. If the pin is clearly bent, replace the valve core or the tube. |
| Valve pin won't unscrew or screw in. | Corrosion or dirt on the valve tip. | Apply a few drops of rust remover or penetrating oil to the affected spot. Keep it off the tire and brake surfaces! Wait, then test again whether the pin moves freely. |
| Valve leaks air even though it was “closed.” | Replaceable valve core was accidentally loosened (same thread direction as the knurled nut!). | Screw the core back into the stem. To do this, turn the flat surfaces just above the valve stem clockwise with a special tool (A-shaped) or needle-nose pliers. |
| Pump gasket doesn't seal properly, air escapes while pumping. | Pump gasket is worn, or the pump head isn't seated straight on the valve. | Hold the pump head on the valve as straight as possible with your second hand, push the pump onto the valve with a light touch, and replace the pump gasket. |
| Air loss with no audible or noticeable leak between valve stem and pump head. | Pump piston seal is worn, or there's a defect in the tube or at the transition to the valve. | Remove the tube, inflate it slightly, * and look for escaping bubbles under water. Repair the tube if possible or replace it. |
* For TPU tubes, inflate only up to 0.3 bar (about 4.4 psi) as long as they aren’t mounted in the tire and rim.
Product Series
ROAD SERIES
Ultra-light, super-fast and mega-compact: AERON/TPU road bike tubes are trimmed for maximum performance. Depending on the discipline and intended use, they guarantee you the perfect set-up with a focus on maximum weight saving and minimum rolling resistance or outstanding puncture protection.
CX/GRAVEL SERIES
TPU technology, perfectly designed for off-road use: Lightweight, puncture-proof, low rolling resistance and the smallest pack size. AERON/TPU offers high-performance tubes for gravel and cyclocross racers as well as variants with maximum puncture protection for bikepackers and ultra-riders.
MTB SERIES
Tech for trails: AERON/TPU provides the perfect tube technology for mountain bikers with the best compromise between lightness, puncture resistance and low rolling resistance. Specific models offer you the perfect tube for your favourite mountain bike discipline, depending on your preferred terrain or riding style.
CITY/TOUR SERIES
Developed for bikers who want maximum reliability in everyday use. AERON/TPU tubes for city and touring are characterised by optimised puncture protection. Their low weight and low rolling resistance also increase performance and the fun factor on every tour.
