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Do Carbon Fiber Bikes Break Easily? What You Need to Know

Carbon road bike frames are made by weaving carbon fiber strands and then setting them within a hard epoxy resin. They are very light, strong, and reasonably stiff. Because of their incredible strength-to-weight ratio, carbon fiber bikes are the most popular performance bicycles on the market today. But do carbon fiber bikes break easily? 

Carbon fiber frames are not prone to breaking. Carbon fiber can be tougher than steel and quite safe when made well. But when made incorrectly, carbon-fiber components can easily break. A carbon bike can theoretically last forever if you don’t crash hard or take a hammer to the frame. 

Steel and aluminum last only so long before the metal fatigues and can no longer be used safely, but carbon remains stable indefinitely. 

The material is also simple to shape into aerodynamic shapes, allowing engineers to experiment with variable strength or flex in critical areas of the bike. 

close up of a carbon bike frame

What Are Carbon Fibers Made Of?

About 90% of the carbon fibers are made from polyacrylonitrile (PAN). The remaining 10% are made from rayon or petroleum pitch. 

All of these materials are organic polymers. It’s an incredibly small diameter fiber characterized by long strings of molecules bound together by carbon atoms. 

How Are Carbon Fiber Bike Frames Made?

Most frame manufacturers construct frames from sheets of carbon fiber pre-impregnated with uncured resin – better known as pre-preg – and are distributed on big rolls. Because the resin activates with heat, these pre-preg sheets are kept in the freezer until needed. 

This method ensures equal resin coverage across the frame, increased control over the lay-up, and reduced labor time. Most of the time, the fibers in those rolls are unidirectional, with all of the fibers running in one parallel direction. This orientation delivers the greatest strength and stiffness in only one direction.

Most carbon fiber frames undoubtedly have a similar origin story – the brand identifies the purpose of the frame and that there is a market for it. After all, if you commit significant resources, you should be certain you can commercialize it.

How Hard Is It To Break A Carbon Bike?

This is determined by the carbon frame. If you choose a cheap, lightweight frame, it will most certainly break easily. On the other hand, a frame from a respected brand is far more likely to be more robust. Carbon frames do not break easily but can be more susceptible to certain kinds of damage than standard metal bike frames. 

This is because the strength of carbon frames is derived from the solid design and a good manufacturing process. Another advantage of purchasing a carbon frame from a respected brand is that they will have produced numerous prototypes and will most likely address any flaws.

Carbon fiber bikes are becoming more dependable, with cracks becoming less common. Carbon bikes, however, do crack. This is frequently caused by previous frame damage and manufacturing flaws. Stop riding if you see a crack in your frame, as carbon is notorious for failing dramatically.

If you want to watch an intriguing comparison between carbon and aluminum frames, here’s a video for you: 

How Long Do Carbon Bikes Last?

How long your frame will actually last depends on your riding type (road, MTB, BMX, etc.) and how careful you are with your bike. Modern carbon frames are becoming more dependable, with a more consistent build quality. As a result, carbon frames and components have a longer life expectancy.

The biggest bike manufacturers that create carbon fiber frames and forks agree that the average life of carbon is 5 to 7 years if ridden or 7 to 10 years if left alone. However, this is mainly determined by how the carbon is stacked during manufacture, the resins used and how they were utilized, and how the frame is used or mistreated.

As a general rule, the lighter the carbon frame or component, the less abuse/riding it can withstand. The weight is reduced by focusing the strength on the carbon layers in the most important/structural places. Put another way, lighter, thinner carbon frames are unlikely to endure as long as thicker, heavier frames.

How To Tell If Carbon Bike Frame Is Cracked?

To keep your bike in top condition, it is best to keep a close eye on it. Pay extra attention while inspecting if you’ve just been involved in a crash. Here are some steps you can take; 

1. Examine For Scratches 

 Look for scratches or worn marks. Make sure to examine the frame on locations that are under force, like: around the bottom bracket, headset, rear dropouts, etc. Also, inspect the area around any brake mounts or pivots.

2. The Tap Trick 

Suppose you notice any deep scrapes or areas of concern. Take a coin and tap softly around the area. A normal ticking sound will be ‘high pitch.’ Keep an ear out for any changes in pitch or sound. 

A broken carbon frame will produce a dull sound instead of a high-pitched one. You can also test for movement or flex by pushing with your fingertips.

 3. Get An Ultrasonic Exam

An ultrasonic exam is the best approach to determine whether a carbon frame is fractured or damaged. This will most likely cost around $100 (£60), but it is a small price to avoid shattering your frame and landing you in the hospital.

Conclusion 

Carbon fiber bikes are designed to be lighter and offer more effortless mobility. The carbon frames, when made correctly, are pretty strong. Carbon frames are relatively sturdy and can resist tremendous force, but only when applied in the intended direction—for example, road shock from a pothole. 

Frequently Asked Questions 

What is the lifespan of a carbon fiber bike frame? 

As long as you keep up the maintenance, it can last 5-7 years if used frequently. Infrequent use will stretch the lifespan to almost 10 years. 

Does carbon fiber break down over time?

Carbon fibers are fused together using resin, which is susceptible to breaking down. It is theoretically possible for your frame to deteriorate with time. 

Are carbon fiber bikes repairable? 

Yes, they are. You can epoxy new carbon fibers in the exact same direction as the original ones.