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Why Your Bike Tire Keeps Going Flat (And How To Fix It)

If you are an avid cycler, you have probably experienced a flat bike tire before.

Most of the time, it’s pretty obvious why your tire has gone flat.

You can usually spot the problem, whether it is a puncture, tear, or something else. 

However, sometimes there are other reasons why your bike tire keeps going flat.

It can be frustrating if you keep losing air without any discernible cause or solution.

Here are some of the most common reasons that bike tires go flat and how to spot them. 

1. There Is a Pinhole Leak

Pinhole leaks are relatively common, but they can be frustrating.

That is because they are difficult to spot and diagnose. 

Usually, when you ride over something and puncture your tire, the problem is apparent.

However, sometimes you might ride over something so small that it gets embedded in the tire without you even noticing. 

A pinhole leak is small enough that it doesn’t show from the outside.

Instead, the object punctures in the inside tube.

It causes a slow, steady leak when there is sufficient pressure inside the tire.

Most of the time, the rubber is tense enough to keep the leak from being visible. 

This can be irritating since it isn’t fixed by simply replacing the tube.

If the object is still stuck in the tire lining, it will merely puncture the new tube once you re-inflate it.

How To Spot a Pinhole Leak 

Spotting a pinhole leak can be a challenge.

To check if you have one, deflate your tire and take it off the rim, making sure to mark the tube and tire, so you know exactly how they were aligned.

Submerge the inflated inner tube in a bucket or other container and squeeze it.

If you see bubbles, you will know it has a pinhole leak. Mark the position of the leak. 

Then, compare the position of the tube leak against that of the tire.

Look to see if you can find anything at that position on the tire.

If you still don’t see anything obvious, slide a cotton ball along the inside of the tire until you feel it snag.

The Solution

As annoying as it is to diagnose a pinhole leak, fixing it is very straightforward.

All you have to do is remove the object causing the puncture, usually with pliers or, depending on the size, tweezers.

Then patch the inside tube with a patch kit. At this point, you should be able to inflate your tire. 

mountain bike flat tire

2. The Tire Is Worn

With time and use, your tire will become worn.

When this gets extreme, the threads of the tire can become exposed to the elements.

This makes it much more vulnerable, and you run the risk of tears or punctures.

Sometimes excessive wear can cause the tire tube to stretch too much.

Either of these issues can cause your tire to go flat. 

How To Know If It Is Time To Replace Your Tire

If the threads in your bike tire are exposed, it is time for a replacement.

It is even better if you replace the tire before it gets worn enough to fall apart like this, otherwise your bike tire keeps going flat but there’s no puncture.

A better practice is to replace your tires when the rubber becomes flat instead of round. 

The Solution 

The best practice for replacing your tires is to swap them out when they start to lose their shape.

Even if your tires wear down at different rates — and they are likely to — replace them simultaneously.

This way, you can ensure that your bike tires are in the best possible shape to perform well and keep you safe. 

3. You Have a Snakebite

This doesn’t mean a literal snakebite!

A snakebite, also called a pinch flat, happens when you hit an object with enough force that the edge of your rim cuts through the inner tube.

This results in two punctures in your tire, hence the name “snakebite.” 

Objects that commonly cause snakebites include railroad tracks, potholes, and rocks.

They are more likely to happen if your tires are under-inflated or too narrow. 

You can avoid snakebites by using tubeless tires, but this might not be an option for everyone.

So how do you when you have one and how do you fix it? 

How To Know If You Have a Snakebite

If you have been losing tire pressure, check for the characteristic signs of snakebite.

Especially consider this if you have been riding in rough terrain.

If you have two punctures an inch or two apart, you will know that you have a hole in your inner tube. 

The Solution

To avoid snakebite flats, you can take a few steps.

Firstly, make sure that your tires are at the proper PSI for your weight.

Uninflated tires shudder more on rough roads.

This causes them to react more violently to obstructions, increasing the likelihood of punctures. 

Secondly, make sure that your tires are the proper width for your bike.

Wider tires provide more air pressure, which makes them less likely to puncture.

If you have experienced frequent snakebite flats, consider getting wider tires, especially in the rear of your bike. 

You can also reduce your risk of getting snakebite flats by improving your technique on rough terrain.

This takes time and practice to learn to drift over obstructions rather than bumping over them. 

Pinch flats can be challenging to patch.

This is because there are two holes, not one.

You may have to use a larger patch to make sure that you cover both punctures adequately. 

4. You’re Experiencing “Burping”

If you have tubeless bike tires, they may be prone to “burping.”

This happens when external pressure causes the tire to separate briefly from the rim, expelling a burst of air.

It can happen more often if your tire rim is warped or not fitted properly, causing a weakened seal. 

It can also happen when your rims are too narrow, not fitting correctly to your tire.

In this case, you will need to replace one part or another to make sure they fit together. 

How To Recognize Burping 

Burping often occurs when you jump and land hard, usually during off-roading or mountain biking.

If you have been riding in rough terrain and notice your tires suddenly losing air pressure, you might have experienced burping. 

If you have inexplicably lost air pressure but can find no punctures or signs of damage, you can be reasonably sure that you have experienced burping.

Unfortunately, you will need to rule out other damage before coming to that conclusion. 

The Solution

If you have been experiencing burping, you will probably need to replace the tire altogether.

You may also need to replace the rim or swap one or the other out for a more appropriate style.

If the problem persists, you might need to avoid rough riding on that bike. 

5. Your Tire Is Over-inflated 

Over-inflating your tire can also cause it to go flat more frequently.

This is because inflating them too much makes them more liable to get damaged.

If there is too much air in the bike tire, it will be uneven.

This causes more wear on the center tread — not to mention that it will slow you down.

But worst of all, overinflated tires are much more likely to be punctured or torn.

That is because they wear down unevenly.

How To Know If Your Tire Is Overinflated 

Every tire has a PSI marked on the side.

You may also need to adjust the PSI based on your weight as well.

Under- or over-inflating your tires is a sure way to increase your risk of making your tire go flat. 

The Solution

Luckily, the solution to this problem is relatively simple.

Always make sure you inflate your tires to the proper PSI.

You can find out what this is by looking at the instructions on the tires and comparing them to your weight recommendations. 

How To Keep Your Bike Tires In Good Shape

There are many ways to patch your tires on the road. It is always a good idea to carry a patch kit with you.

This might include a tire lever, patches, air pump, and other tools.

Although punctures and tire damage are sometimes avoidable, the best way to keep your tires in good shape is to address the underlying problems. 

First off, make sure that you have the correct size tire and rim.

All the parts should coordinate.

Many bikers now prefer using wider tires to improve the air cushion and reduce the risk of flats.

Of course, you should also make sure that they are inflated to the proper PSI.

Double-check this by referring to your tires and cross-checking against your weight. 

Keeping your bike tires in good shape also depends, in part, on your riding technique.

If you have been experiencing frequent flats, you may want to review how to improve your approach to protect your bike.

By making these small changes, you can protect your equipment for the long term.

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