How to Tell if Carbon Bike Frame is Cracked?

I thought owning a carbon bike frame meant I was sorted for the rest of my life. About two weeks ago, I had a terrible fall. The worst part is that I forgot to check my carbon frame after the crash. So, when I started riding it again after a week I could hear a sound that was not there before.

That’s when I got suspicious. But, after thorough research, I knew it was a crack. Guess what? I repaired it in no time. You can land in such a situation too. So, if you want to learn how to tell if a carbon bike frame is cracked, then hear me out.

Why do Cracks Happen on a Bike Frame?

You may wonder why cracks even happen in the first place. Well, several factors contribute to cracks such as:

1. Environmental Factors 

High temperatures can affect the quality of the materials. This leads to the frame becoming brittle and can expand or contract irregularly. Besides, exposing the frame to moisture and salt can cause it to rust. This weakens the frame and leads to a crack. Extreme weather conditions such as floods and hail storms can cause a crack.

2. Manufacturing Defects 

There could be a flaw during the manufacturing process. It can be material inconsistency, poor welding, or any other thing. So, when you subject the frame to repeated stress while riding, it is going to crack. 

3. Stress

With time, continuous stress as a result of riding can lead to frame cracks. Sometimes you carry an excessive load on your bike or use it for something that the bike was not designed for. This will ultimately result in frame failure. Moreover, riding a bike that is too large or too small is wrong. This would put undue stress on certain areas only and cause the frame to crack.

4. Accidents

Impacts like hitting a pothole or a fall can immediately damage the frame.

5. Fatigue

It is normal for a material to age and when this happens, it develops fatigue. Material fatigue and mechanical stress during the ride results in a crack.

How to Tell if Carbon Bike Frame is Cracked?

Those who own a carbon bike frame know what I am talking about. But, if you are someone looking to purchase a carbon bike frame, let me break it for you. A carbon bike frame is manufactured from a composite material. Therefore, a carbon bike frame is delicate but lightweight and durable.

Now, let’s come back to your question. How to tell if a carbon bike frame is cracked? Or whether it is a carbon frame crack or paint damage? 

There is a simple way to check for a crack on a carbon bike frame. Grab something metallic such as a coin. Tap it lightly on the area where you feel there is a crack. If you hear a hollow sound, the carbon frame is cracked. A full sound indicates a normal frame.

I have mentioned some other symptoms of a cracked carbon bike frame below. So, stay with me.

Signs of a Cracked Carbon Bike Frame

• Fracture or crack that is visible on the bike frame
• A damaged or chipped paint 
• An unusual creak or noise during biking 
• Difficulty in handling the bike 
• Change in the stiffness of the frame 
• Change in the stability of your bike

Tools and Techniques for Detecting Cracks

Sometimes a crack is not visible. If you take your bicycle to a specialist, he will use rather advanced techniques to detect the crack. These techniques could be:

• Ultrasonic testing
• CT scans
• X-rays
• Liquid penetrants

What to Do If You Find a Crack?

You just detected a crack. Great. Now you are wondering, can you fix a cracked carbon fiber bike frame? Yes, you can. You can repair it by following these steps:

• Start by cleaning the damaged surface. For this, you can use either a degreaser or a rubbing alcohol. Make sure you do not skip this step. 
• Next, you need to apply a small amount of epoxy with the help of a brush to the damaged area. Apply it in a way that covers the whole area. 
• Now insert the reinforcement. Inserting a piece of carbon fiber would reinforce the damaged area. Ensure that the carbon fiber is longer as compared to the damaged area. This is done for better adhesion and a repair job that lasts longer. 
• You need to cover the carbon fiber. Again apply epoxy to the area. 
• It’s time for the epoxy to cure. This would take about 24 to 48 hours, varying from manufacturer to manufacturer. To know the exact curing time, follow your manufacturer’s instructions strictly. 
• Now you have to sand the damaged area. With the help of sandpaper, smooth out the area you just repaired. 
• Lastly, you are required to paint the entire repaired area. Do it in a way that matches the rest of your carbon bike frame.

Now that you’ve fixed your bike, you may think there is nothing more to do. Wrong. Stay and see how you can prevent carbon bike frame damage.

How to Prevent a Carbon Bike Frame from Cracking?

As it is said, prevention is better than cure. This applies to carbon bike frames too. I know every material wears over time. But, you can slow this process with some preventive measures like:

• Avoid going for a brand that offers a carbon bike frame at a cheap price. This is because if there is any defect in the product, your frame will not last long. Invest wisely.
• Choosing the correct fit is a necessary thing when purchasing a carbon bike frame. A perfect fit will distribute your weight evenly, preventing more stress on the frame.

Learn more about: What Size Bike Frame Do I Need?

• Do check your frame thoroughly for a crack, dent, or any other damage after each ride. Do not forget it, especially after a ride on rough terrain.
• Avoid impacts as much as possible. Do not hit a curb, pothole, or any other kind of obstacle. When locking your bike, use caution to prevent any harm.
• Clean and maintain your bike frame regularly. Always keep the moving parts lubricated to avoid corrosion. You can also apply wax or protective frame sealant to your frame for better protection.
• If you see any worn part on your bike frame, get it replaced. These worn parts would put extra stress on your frame, leading to a crack.
• Always ensure that your weight is evenly distributed on your bike frame. Overloading should be avoided at all costs.

This was all about a carbon bike frame. However, there are bike frames of other materials available as well. So, you may wonder how to identify a crack in an aluminum frame.

Here is how. Similar to a carbon bike frame, the first thing you need to do is check for any visible cracks. But, a professional would use various techniques to look for a crack. These include:

Keep one more thing in mind before you go. Riding a cracked carbon frame is not a good idea. It can fall apart as soon as you go down a large hill or when you are in traffic. This can be life-taking and extremely dangerous for you. You can use it for on-road riding. Still, it is not safe to do so. It is always better to get it repaired.

Conclusion:

One cannot deny that a carbon bike frame is a great investment. With proper care and maintenance, you can make the product stay with you for long. If there is a crack, this guide would be sufficient. However, if you feel that the damage is a huge one and you cannot deal with it on your own, seek professional help.