Why Did My Tubeless Tire Go Flat?

Whether it happens out on the trail or overnight in the shed, a flat tire is one of the most annoying things all cyclists have to deal with at some point.

When it comes to tubeless tires, however, it can be even more difficult to understand the problem, particularly if you’re new to using a tubeless setup or if there isn’t any clear sign of the problem.

To understand why your tubeless tire may have gone flat, it’s important to understand what they are and how they work.

Traditionally, bike tires have used inner tubes which are inflated to a certain psi and used to give tires rigidity and strength.

Without an inner tube, bike tires wouldn’t be able to function at all and this would make for some very uncomfortable, very unsafe cycling.

However, inner tubes are prone to many issues, such as punctures, pinch flats, and can also be awkward to fit correctly.

 Inner tubes also have a tendency to lose pressure quickly and can deflate very rapidly which is dangerous, particularly when you’re hurtling down a trail or speeding along a road.

Traditional tire and inner tube setups also had to be run at quite high pressure in order to prevent puncturing and pinching, however, this seriously reduced the traction these setups can offer due to being unable to use low psi for added grip.

The solution to many of these problems can be found in going tubeless.

Tubeless tire setups are not necessarily a new thing, and many patents were submitted for different designs throughout the 20th century, however, engineers could never find a way to make these designs work.

Perhaps there was a lack of precision that can only be achieved using modern processes, or maybe the materials used in modern manufacturing have helped to make tubeless tires functional.

Whatever the case, in the cycling world tubeless setups are the hottest new trend and are displacing a lot of traditional inner tube setups due to the many benefits they offer.

One of the main benefits of a tubeless setup is that it can run at lower psi settings which adds a huge amount of grip compared to high-pressure inner tube configurations.

There’s also the fact that tubeless tires are not prone to pinch flats, since they don’t use inner tubes at all, removing one of the core reasons for punctures altogether.

Tubeless tires are also able to use a sealant, which means that if a picture does occur when you’re riding, tubeless tires are capable of self-sealing the hole, preventing rapid air loss, and even making punctures unnoticeable.

This leads us to our next point.

The Main Explanations

Due to the fact that tubeless tires deflate far more slowly than traditional inner tube tires, one of the chief reasons your tire is going flat is because there is a puncture you haven’t identified from a previous ride.

However, this isn’t the only reason.

If you haven’t used your bike yet and you’re still noticing a loss of pressure in your tires, it's possible that your sealant levels are too low or that the tire isn’t properly seated to the rim, which is imperative to preventing air loss, particularly around the valve area.

It’s also possible that your tire may have become bent if it’s new out of the box, meaning that the beading won’t seal correctly. Flattening out your tires before fitting them is the best way to avoid this.

Some riders also have issues with their wheel tape, which can sometimes fail to fix properly. Making sure to use tape in warm environments will help the adhesive to work more effectively.

Another important step is to make sure that the rims are clean before you apply tape, to prevent dust and particles causing bumps and bubbles in the tape as you apply it.

When you apply your tape it’s best to start near to the valve so that you can keep track of where you need to stop and won’t have to overlap very much.

As you apply the tape take care to check the rim and press down on the tape hard to help it stick well.

Cutting a tiny hole in the tape and then pushing the valve through it will help keep the integrity of your tape intact while allowing you to create the best seal possible.

An overtightened value can also cause your tire to deflate - as the seals can be too compressed and can warp.

If you notice a leak around this area using sealant to try to fix the issue is best. Adding a little around the valve will help to seal any small holes.

My tire is flat but I can’t find the leak?

If you’re having trouble finding a leak but your tire is still deflating then it’s definitely time to break out this old trick.

Fill a bowl with clear water and place your tire inside it. As you work your tire through the water slowly, watch for any bubbles that may appear, even very small ones.

When you see bubbles in the water, you’ve honed in on where the leak is, and can gradually find the exact spot where the air is escaping.

This will allow you to assess how best to fix it, depending on where the puncture is located.

Another little trick to help you seat your tires effectively is to lubricate the beads a little bit as you seat them. This helps the beads to pop into place more easily.

You can use a little bit of soapy water to do this, or even spray a little bit of silicon polish on them if you have it available. This will help the beads get into position and has the added benefit of helping prevent leakage. 

Just remember to keep this stuff well away from your brakes and other components, and only use it if you’re really having issues seating the tire yourself.

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