The bicycle industry has adopted carbon fiber in the same way traditional manufacturers have used steel. Carbon has revolutionized the frame in the bicycle industry, but how long can it last? Matt Wikstrom, an Australian tech editor, tries to answer this question by interviewing three bicycle industry engineers.
Nearly three decades have passed since carbon fiber made its debut, and despite its dominance in road bikes, save for the entry-level models, the material’s reputation is still tarnished by the industry’s early efforts. I often encounter the robustness of carbon bikes and their long-term viability among owners. But composite frames remain a popular choice for racers, and there is no better option for a lightweight custom bike build. Nonetheless,
Early carbon bikes (like Look’s KG86) lacked robustness and dependability. Frames made from carbon tubing and aluminum were lighter than their steel counterparts, but the materials were a terrible mismatch. Epoxies in use at the time were rendered ineffective by galvanic corrosion and, to a lesser extent, UV exposure, resulting in the collapse of the frames.
Faith in carbon fiber
Throughout the 1980s, carbon composites and manufacturing methods advanced significantly, and independent testing has consistently shown superior fatigue resistance for the material. According to senior engineering manager Chuck Texiera, it’s “almost like going through the motions” for Specialized’s fatigue tests. “We’ve never seen a single instance of failure or exhaustion. Fatigue is a foregone conclusion once you reach your predicted maximum strength. In most cases, if you put any metal frame through the same number of cycles, it would fail. “It’s awe-inspiring.”
Benoit Grelier, the head of Scott’s bicycle engineering, gave a clear answer when I asked him about the lifespan of a carbon bike: “I think it can last your lifetime.”
Even vice president of research and development and engineering Scott Nielson has worked with carbon fiber for over a decade, starting with Trek, before joining Enve. According to him, “When it comes to fatigue testing,” he stated: “carbon materials are far superior to aluminum or steel when it comes to fatigue.” A well-made frame could last a lifetime.
Exceptionally durable carbon fiber is the reason for this confidence level. Chuck Texiera said, “Composites don’t behave like metals.” They don’t wear out like metals in the traditional sense. “The fiber’s fatigue life is practically infinite.”
The interplay between carbon fiber and the resin
Bicycle frames are not made entirely of carbon fiber but rather a combination of fiber and resin. To put it another way, the result is akin to reinforced concrete, in which carbon fiber serves as reinforcement for the epoxy resin. Grelier described it as “truly a matrix.” “The resin is the glue that binds the fibers together. You’ll have better material if they’re well-suited to one another.
Carbon composites’ quality and dependability have improved in recent years due to new research into the interplay between the two components. Strong fibers are essential, but the resin must thoroughly penetrate them, minimize any voids (literally, air bubbles), and properly dry the resin.
Because of this, resin’s ability to withstand the elements and hold up over time is compromised if not fully cross-linked, as Texiera explained. Despite our best efforts, the end-user can’t know. We can determine if the resin has fully cured by conducting failure analysis.”
Then there’s the issue of varying starting materials. In the case of Scott Nielson and Enve, they’ve discovered that carbon fiber can vary significantly from batch to batch. Composites, he explained, “always pose that kind of problem.” Every month, we sample a certain number of products and test them to ensure that the materials and the process haven’t changed over time.
The weaknesses of carbon composites
As a result of their high weight/strength ratio, carbon fiber composites are more vulnerable to high loads applied to a small surface area, such as an impact. Matrix starts to crumble once the composite integrity is compromised and must be repaired or replaced.
The matrix can degrade with use even if no impact is made, but this process takes an extremely long time. Chuck Texiera said that at some point in the epoxy matrix, “little cracks” will develop, and “over time [the epoxy matrix] will just be connected by fiber.” So what’s happening is that the frame’s stiffness will change slightly over time, but the change is so tiny that it’s hard to notice. It’s quantifiable, but I doubt anyone would notice it. In reality, it will take a lot longer than that. Any typical age group racer wouldn’t be able to accomplish that in two years.”
Chuck Texiera pointed out that some threats are easily overlooked despite carbon composites’ robustness. He said that maintenance, dismantling, and overcooking clamping pose the most significant dangers. “Also, traveling by bike isn’t the best option.”
To ensure the integrity of the composite, avoid any impact or excessive local forces. Nevertheless, what about the surrounding environment, particularly the constant exposure to the sun? Texiera says there’s nothing to be concerned about. Epoxy and resins are generally excellent today. A place like a moon would be ideal for burning off the resin. Even when they’re clear-coated, bicycles are painted with UVA-resistant paints. There is also some UV tolerance in the resins.”
Improving the impact resistance of carbon composites
Carbon composites have improved impact resistance over the last few years to the point where MTBers are now fully embracing them. The advancements in resin technology are primarily to blame. When asked about working with materials that can withstand impact, Benoit Grelier said, “We have the stiff enough materials.” Playing with resin and nano-components has yielded some promising results.”
According to Grelier, “Standard resin is like oil, whereas nano-resin is like water.” “Oil won’t go through a mesh because it is thicker, whereas water will go right through it. The final bonding will be stronger if I use a nano-resin instead of a traditional resin.
Chuck Texiera has experienced similar outcomes. For the past 30 years, “the fiber has not changed much,” he said. Fibers have improved quality and toughness as resin systems have spread, filling in gaps and improving bonding. However, there still is room for improvement.
Scott Nielson concurs. Keeping an eye on the outcome will be an exciting exercise. More work needs to be done before those materials can genuinely produce a truly dramatic improvement.” Now, we are seeing new materials that incorporate some of those nano-enhancement or nano-tougheners that have been in development for years.”
The influence of cost
High-price carbon frames are typically valued in weight savings and performance gains over their lower-priced counterparts. Does the price of a bike affect how long it lasts? Is it reasonable to expect a more expensive frame to last longer than a cheaper one?
According to Chuck Texiera, laying down the carbon fiber plies “is a big part of the cost” and how many plies there are. Many cheap frames have few thick plies instead of many high-priced frames that have many thin plies. So a lot more plies are working for you.”
The cost of construction directly impacts the level of quality it achieves. According to Chuck Texiera, “typically a low-cost frame, they are not that diligent at getting all of the trapped air and resin out of the system. A more expensive frame may last longer due to the higher quality of construction and materials used, but the current market trend is to meet consumer demand for weight reduction.
High-cost frames are typically constructed with less material than low-cost frames due to this fact. Benoit Grelier assured everyone that “both of them are safe.” “However, I believe that a crash with a lightweight frame poses a greater risk of damage.”
Chuck Texiera advises that to achieve the maximum benefit from carbon, “there should be a balance between the lightweight, crush resistance, and longevity. We tend to stay away from ultra-light platforms since, while they are efficient in weight, they will demolish if they are subjected to unexpected forces. That’s not a good place to be.”
Designing for failure
Composites are vulnerable to catastrophic failure due to their vulnerability to impact damage. You’ll find numerous examples of carbon frames and forks breaking in a crash in a quick internet search. However, such catastrophic failures can be avoided, protecting the rider and preserving the brand’s reputation at the same time.
The same product can fail in different ways depending on how the layers are handled, according to Benoit Grelier. There are two possible outcomes: it can collapse and break into two pieces or crack but remain intact.
As Steve Nielson once said, anyone can break a product if they work hard enough. Products aren’t indestructible, especially when you’re looking at high-end products. When it comes to testing, even though we have a minimum requirement, we’re expected to go above and beyond that requirement. And if it does fail, it must do so in a way that does not put users at risk. We’re looking for a way to break it, so the rider doesn’t get blown away.”
Manufacturing defects and consumer confidence
Even though composites are widely regarded as solid and durable, there is a degree of doubt in the minds of consumers. Anecdotal reports about the relative brittleness of carbon frames abound on the Internet, and it appears that every other rider has had one replaced under warranty within a year or three of purchase.
It is impossible to determine the true incidence of defects/failures without data on returns and replacements. According to industry insiders, the rate is less than 1%, but a significant manufacturer can produce thousands of defective bikes each year even at this low rate.
Despite the many reasons defects occur, it’s essential to keep in mind that they can happen with any construction. Between the layers of carbon fiber, voids and wrinkles form, hiding most defects in composite materials. Carbon fiber is a byproduct of combining hundreds of carbon fiber pieces to form a composite frame.
While this method allows for much creative control over the final product, it is also notoriously prone to errors. Engineers Raoul Luescher and Chris Meertens spoke with James Huang about this topic in a recent podcast.
“The more plies you lay down, the greater the likelihood of introducing air into the laminate,” explained Chris Meertens.
Insidious defects that often go unnoticed unless extreme measures are taken are formed when air is trapped. De-lamination and structural failure are inevitable due to these defects, primarily if the defect occurs in an area with a lot of loads.
The whole theory of placing fibers and everything going as planned, where every fiber is in the right place, is unrealistic in composites. You need to prove your claim.
X-ray tomography and ultrasonic inspection, expensive and time-consuming processes used by the aerospace industry, are typically involved. With mass-produced bikes, there is little time to conduct the same level of inspection as there is in the automobile industry.
However, this does not imply that the industry is sloppy. Manufacturing processes have been simplified, and raw materials have improved over the last two decades, reducing the likelihood of defects. X-ray tomography is now used by some companies, such as Canyon, on every fork they sell as part of their quality control procedures.
A better bike can constantly be developed. Just because the ones we have now may be the best in history does not preclude future improvements, according to Leuscher.
The future for composites in the bicycle industry
From the design and engineering to the improved materials and manufacturing of today’s carbon road bikes, it is clear that enormous progress has been made over the industry’s early efforts. Carbon bikes continue to command a high price, but low-cost carbon bikes have seen significant growth in recent years.
What can we expect from the consumer market for the future of carbon bicycles? The majority of university-level research, according to Steve Nielson, “remains academic. I am looking forward to seeing how the findings are applied in the real world. I believe new materials are on the horizon, and many approaches are being considered to improve the ductility of composites. As more and more of the material is used in the automotive industry, it will be interesting to see how it changes.”
Benoit Grelier is investigating a few materials that aren’t entirely carbon fiber-based. “Kevlar has the potential to be an interesting player in this scenario. Self-healing composites have been tested but haven’t made much progress.”
There is a good chance that the manufacturing processes themselves will be enhanced. As an illustration, vacuum de-bulking is expected in the aerospace industry during the laminating process to eliminate any remaining air. Because it has to be done every two plies, it slows the production down.
As Chris Meertens put it, “Vacuum de-bulking is not commonly used in the bike industry.” There is a problem with the way most factories operate. Seeing a wholly retooled factory is what I believe is necessary for adoption..”
It will take time to make these improvements, but the last two decades have shown that consumers enjoy carbon fiber composites and that the material has much to offer the bicycle industry.
Do Carbon Fiber Bikes Break Easily?
Because of the high-quality materials used to make carbon fiber bikes, they are resistant to breaking. Carbon fiber bikes are made from only the best materials, so the weave and epoxy are constantly being improved.
The design and construction of these bicycle frames ensure that they are strong where it is most needed. There’s no doubt that a bike frame made of carbon can withstand wear and tear.
Lab testing has shown that carbon fiber bike frames outperform alloy ones, and you can find many models with excellent impact resistance.
The majority of the problems and breakdowns that occur in carbon-framed bikes result from user error, not the bike itself. Taking care of and maintaining your bike is critical to its long-term viability.
Carbon Bike Frames: How to Care for Them
Carbon bicycle frames are known for their durability and dependability.
Make sure your carbon frame is correctly cared for to extend its lifespan.
Fortunately, taking care of a carbon frame doesn’t require much effort, especially if you’re already familiar with bike maintenance.
Carbon bike frames can be maintained in various ways, and the following are some of the most common.
For the final time, a high-quality carbon bicycle can outlive its owner. As long as the bike is correctly cared for, this should be no problem. According to the top carbon fiber frame manufacturers, carbon fiber frames and forks typically have a lifespan of 5 to 7 years if they are regularly ridden and 7 to 10 years if they are not regularly ridden.
This is all I can tell you at the moment! Hopefully, you found this post about carbon bike frames helpful. If you need more help, I am available.