How to Deflate a Bicycle Tire Completely the Correct Way: Presta, Schrader and Dunlop Valves

There are plenty of times when I am taking my bike for a plane ride cross country to go for a bike tour and I don’t want the change in cabin pressure to be cause for my tubes exploding when I land, so I typically will deflate the bicycle tire completely.

My bicycle is a road bike, so I have Presta valve. However, I will explain to you how to deflate each valve.

If you are having any questions about why your tires are losing air, then this guide will help you.

Presta Valves are more common for high pressure wheels, and it is easy to deflate a bicycle tire with Presta Valves. For the other options of Dunlop valves and Schrader valves you have one extra step in between.

For the three options, I recommend going to the table of contents and pressing your valve type to go directly to the instructions. As long as you treat your tubes and valves well, your tires will last for a very long time.

How to Deflate a Bicycle Tire

There are three types of valves to deflate. Follow these instructions for the three types:

• Presta Valve
• Schrader Valve
• Dunlop Valve

Did you know?

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Presta Valve

Presta valves are very common amongst fixed wheel bikes, road bikes and mountain bikes. They hold high pressure air more securely and are fashioned so that the wheel’s integrity can hold stronger because the whole inlet in the rim is smaller.

Above is a photo of the Presta valve. Sometimes there will be a black cap on the valve and sometimes there will not be. The black cap is not fully necessary to hold air in the tube and air will not leak if you ride without it.

To release the air of a Presta valve, twist the cap (circled) to the left to unscrew the nut. You can give it several twists to the top and then push the cap down with your finger. You should hear a hiss and cold air come from the tire. 

To refill a Presta Valve, don’t forget your converter if you are using a standard bike pump. I typically leave mine on the wheel when riding so I always have it in case I get a flat while riding.

Fun Fact: The air is very cold because it is going from a state of high pressure to low pressure – a change in state called adiabatic change. It’s the same reason air when released from a balloon, or when you blow air from your lips pressed together is cold.

Schrader Valve

Schrader is the most common amongst bicycles. This will be found on most hybrid bikes and is the same that you’ll find in a car. You can remove the cap by twisting it. Again, the cap can be on or off and will not cause the air to escape.

Unlike the Schrader valve, there is no component to twist. You take a small item to press the center of the valve. A key, a nail, a thick needle are all good options. When depressed the air will deflate.

If you want to release the air faster, you will use a Schrader deflator tool to take out the center piece. You are also able to replace the center piece with this tool and tighten the valve.

Dunlop Valve

The woods and Dunlop valve is very similar to the Schrader valve. You won’t find this very often in the United States, though it is a nice to know.

You twist the valve in the same fashion that you would twist the Schrader. However, the difference with the Schrader is that this nut holds on the top half of the valve and is under pressure.

You ought to make sure to not twist off the cap too quickly or the air will be pushed out too quickly and blow the cap out as well like a miniature air-volcano.

How do you fully deflate a bike tube?

To fully deflate a bike tube, you will need to take the tube out of the tire. The simplest way to take the tube out of the tire is to deflate the tube the way that is explained in the above steps.

After deflating the tube this way, you will take the wheel off of the bike and then take the tire off of the bicycle wheel.

Because your tube is flattened, you should not have much of a problem pinching the wheel off of the wheel.

If you have a road bicycle, or a bicycle where the tire is tight around the rim, consider using a bicycle tire lever. I have used the metal levers and did not like it much because it felt like I was scratching the rim, so I stick to plastic tire levers when taking the tire off of my bicycle.

Now that the tire is off, you can remove the tube and manually deflate the entire tube. The way that you take all the air out is up to you.

When I needed all of the air out to store the tube in a small pack, I deflated went inch by inch and deflated the tube. I also have a air mattress air pump that I rigged with a tube and duct tape and a presta converter to reverse suck the air out when I needed the tube absolutely flat.

Do you unscrew a presta valve to inflate?

If your presta valve is screwed in tight, then yes you do need to unscrew it counter clockwise to be able to inflate the valve.

If you are having other problems with your bike tires inflating, read here for our complete guide.

You will know that the valve needs to be unscrewed if you take your finger and push the valve down from the top. Does the valve move up and down? This means that you are able to add air to the valve.

Does the valve not move (and almost stab your finger)? This means that the valve is screwed on tight and you need to unscrew the valve to allow for air to enter into the tube.

This is a tricky aspect of the presta valve. One other thing with presta valves is that when they are holding high pressure air, you don’t have to screw the valve back in.

However, you should, because if you are riding and something pushes the valve down, then all of the air in the tube will release. Keep in mind that presta valves it is normal to loose some small amounts of air over time.

Conclusion 

You should know how to deflate a bicycle tire for all three types of wheels. They are all easy to understand once you understand the mechanics of them.

I ride a Presta valve now and love the smoothness of the ride at high pressure. Keep in mind that all tires will slowly loose air at some time.

Most recently in the news, the cycling industry is moving towards disc brakes. It may be useful to know if you can use your rim brakes on disc brake wheels.