What is the lifespan of a carbon frame cyclingtips r gasquet


The bicycle industry has embraced carbon fibre u gas hampton in the same way that steel once served traditional manufacturers. Renowned for its high strength to weight ratio, carbon has revolutionised the bicycle industry, but how long can a buyer expect a frame to last? Australian tech editor Matt Wikstrom investigates the answer by talking with three engineers working in the bicycle industry.

Almost three decades have passed since the emergence of carbon fibre and while the material dominates all but the low end of the road bike market, the reputation of carbon fibre still seems marred by the industry’s early efforts. I regularly encounter owners concerned about the robustness and longevity of their carbon bikes while others expect to retire their bikes after just a few years of use. Nevertheless, composite frames remain a common choice, especially for racers, and there is no better choice for a lightweight custom bike build.

The first carbon bikes (such as Look’s KG86) were far from robust or reliable. Carbon tubing was bonded to aluminium lugs and while the frames were significantly lighter than their steel counterparts, it was a devastating mismatch of materials. Galvanic corrosion (and to a lesser extent, UV exposure) would defeat the epoxies in use at the time and the frames would fall apart. Faith in carbon fibre

Carbon composites and manufacturing methods have evolved considerably since the mid-‘80s and independent testing has 76 gas station hours consistently demonstrated superior fatigue resistance for the material. “The fatigue tests that we run here are almost a matter of going through the motions,” said Chuck Texiera, a senior engineer at Specialized. “We just about never see a failure or fatigue. Once you hit expected ultimate strength, the fatigue is like a gimme. If you subjected any type of metal frame — including titanium — to the same total cycles, typically they would p gasol not withstand it. It’s quite amazing.”

Scott Nielson has worked with carbon fibre for over a decade, starting with Trek, and is now the vice president of research and development and engineering at Enve. “If you look at carbon materials in general,” he said, “they’re very good in fatigue, much better than any aluminium or steel would be. If done properly, a frame could last you forever.”

Strictly speaking, bicycle frames are not made from carbon fibre but a composite comprising the fibre and resin. The result is akin to reinforced concrete, where the carbon fibre acts as reinforcement for the resin. “It is truly a matrix,” said Grelier. “The resin is the material that joins all the fibres together. They have to match each other really well, then you will have a better material.”

It is an understanding of the interplay between the two components of the composite that has developed in recent years, improving the quality of the reliability of carbon composites. A strong fibre is of course critical, but there must be thorough penetration of the fibres by the resin, minimisation of any voids (literally, air bubbles), and complete curing of the resin.

“If the resin is not fully cross-linked,” explained Texiera, “then it compromises its ability to withstand 6 gases the elements and to also hold up with time. There’s a way we can tell in the laboratory but for the end user it’s really impossible for them. We can do a failure analysis that can actually tell whether the resin is fully cured or not.”

Then there is variation in the starting materials to contend with. For Scott Nielson and Enve, they have found there can be considerable variation from one batch of carbon fibre to the next. “That’s always a challenge with composites,” he said. “We do a lot of sampling, take a certain number of products every month and test them to make sure there isn’t any drift in the materials or the process.” The weaknesses of carbon composites

In the absence of any impact, the matrix can deteriorate with use, but it takes an extremely long time. “The epoxy matrix will at some point start to form little cracks,” explained Chuck Texiera, “and then over time it will just have the connectivity of the fibre. So really what’s happening, over really extended periods of time, you can expect the stiffness of the frame to change ever so slightly but it’s such a small electricity review worksheet number. We can measure it but I really wouldn’t think it would be perceivable. But it takes hundreds of thousands of cycles to even electricity bill nye get to that. Two years would be far too short for that to occur with any kind of typical age group racer.”

The key message here is to avoid any kind of impact or excessive local forces to preserve the integrity of the composite. But what about the environment, especially constant exposure to sunlight? According to Texiera, there’s nothing to worry about. “Most epoxies and resins today are extremely good. I’m sure you could find some place like the moon where really high radiation levels could burn off all the resin. Bikes are typically painted with UVA-resistant paints, even if they’re clear-coated. Then the resins have a certain UV-tolerance as well.”

The impact resistance of carbon composites has improved in recent years to the point where MTBers are now truly embracing the material. The advances are largely due to innovations in resin technology. “We have the materials that are stiff enough,” said Benoit Grelier, “but the goal is now to work with some materials that have strength in case of an impact. We have had some good results by playing with the resin and nano-components.”

Scott Nielson agrees. “They’ve been working on nanomaterials for years and now we’re seeing new materials coming out that are taking advantage gasbuddy trip of some of those nano-enhancement or nano-tougheners. It’ll be interesting to see what happens. I think it’s a good start but there’s a long way to go for those materials to really truly yield a dramatic improvement.” The influence of cost

Cost also influences the quality of construction as well. “Usually a low cost frame, they are really not that diligent at getting all the trapped air and resin out of the system,” said Chuck Texiera. Thus, a high-cost frame might last longer thanks gas bijoux soho to higher quality construction and materials, but the current market trend is to satisfy consumer demand for weight savings.

“The best way to get the most out of carbon,” said Chuck Texiera, “is to carry a good balance between a light weight, crash resistance, and longevity. Typically we don’t chase the ultra-ultra-lightweight platforms because, sure you could have this very efficient eggshell design, but if it’s subjected to anything like unexpected forces then that thing goes to hell. That’s really not a responsible place to be as a manufacturer.” Designing for failure

The susceptibility of composites to impact damage creates enormous potential for catastrophic failure. A quick survey of the Internet will yield a multitude of instances where carbon frames and forks have snapped into pieces during a crash. However, it is possible to prevent such catastrophic failures and protect the rider as well as preserve a brand’s reputation.

“Anybody can break any product if they tried hard enough,” said Steve Nielson. “Products aren’t indestructible, especially when you’re looking at high end products. Even though we have a minimum requirement, we’re expected to go above that requirement, so we continue to test until failure. And when it does fail, it has to fail in a safe manner. We want it to break in a manner so that the rider will stay upright and won’t get blown to pieces.” Manufacturing defects and gas in oil pressure washer consumer confidence

The reasons for defects are many but it’s important to note that they can occur for any construction material. In the case of composites, the majority of defects are hidden from view in the form of voids and wrinkles that occur between the layers of carbon fibre. They develop as a by-product of hand lamination as hundreds of pieces of carbon fibre are patched together to create a composite frame.