A recent article by the New York Times on the pitfalls of carbon fiber road bike frames glossed over some key points and was almost misleading in its assertions that carbon fiber is a fragile material waiting to snap at the least opportune moment.
The article largely references riders in the Tour De France and the frequency with which bikes break during major crashes. Nevertheless, there’s a halo effect on readers that suggests the material itself poses a risk to even casual riders. Riders in the Tour are at the absolute edge of what is humanly possible on a bike. The most powerful riders in the world are giving 100% effort to win which means pushing their equipment to its absolute limits. A bicycle frame, fork or wheels, when crashed while being pushed to its limits will undoubtedly fail. It’s worth noting the causal relationship between material failure and crashes. The materials generally fail because of the crash, not vice versa.
The article also claims that carbon fiber generally fails without warning. Most bike shops will tell you that when frames fail, they very often offer signs of failure before catastrophic problems arise. Many times a cracked frame will exhibit a creaking or clicking noise that can persist for months before the frame breaks completely. If examined properly, the crack can be caught and the frame warrantied or replaced before it gets worse. All riders should periodically examine their bikes (or have them examined at a shop) to check for any apparent issues.
Not to suggest that the New York Times is engaging in fear-mongering, but the rhetoric used by Mr. Austen lends a certain degree of sensationalism. Words like “shatter” and “explode” hardly summarize carbon fiber frame failures which are most often quite boring. Rarely does a carbon frame fail so spectacularly that it causes catastrophic injury, except in extreme scenarios such as professional racing. Indeed, most frames present signs of failure long before it occurs and even then it is generally in less critical locations unlikely to cause a major event. Most riders will never come close to stressing a frame as much as a professional rider who trains hundreds of miles per week and can sustain a much higher power output for hours at a time.
Two years ago, Santa Cruz Bicycles, a leading manufacturer of aluminum and carbon fiber mountain bike frames released a video in which they failure tested their aluminum models back to back with the equivalent carbon versions. The tests, designed to simulate real world riding scenarios, revealed that the carbon frames could withstand much more abuse than the aluminum models.While lightweight road frames undergo slightly different stresses, the fact remains: carbon is incredibly strong.
As mentioned by the New York Times article, carbon frames start their lives as sheets of cloth fiber which are carefully cut and laid in pre-determined patterns to maximize strength while minimizing weight. Depending on the fiber weave, the directional layup and the amount of material, frame engineers can increase strength in high stress areas while improving overall comfort and ride quality. Cutting edge frames such as the Trek Emonda SLR or Specialized S-Works McLaren Tarmac ($15,000 and $20,000, respectively) undergo hundreds if not thousands of hours of development and testing to present the most advanced carbon construction available. To suggest that carbon construction is as simple as laying fibers down and covering them in epoxy is a gross oversimplification.
The Times also claims “Small spills that used to mean, at best, straightening handlebars often require a bike change.” In reality, there is no such thing as a small spill in a race like the Tour De France. Per VeloNews, the average speed for the entire Tour De France generally hovers around 40kph, or roughly 25mph. The peloton routinely cranks along at 28mph on flats and exceeds 50mph on mountainous downhills. At these speeds, where riders are separated by mere inches, crashes happen quickly and with catastrophic results. Bicycles that become entangled in these crashes have been pushed past their usable limit, and even if they appear intact on the surface the materials are often fatigued to a point where they may fail soon after.
Indeed, many riders in this year’s Tour dropped out because of serious injuries brought about by crashes. Also worth noting is that while the 2014 dropout rate may seem high, the number of riders quitting the Tour has been on a consistent downward trend in almost every decade since 1934. Conversely, rider speeds have been steadily increasing since the Tour’s inception in 1903 when the average speed was a mere 16mph. To summarize, riders are riding faster than ever on more advanced bikes, with a higher overall completion rate.
Carbon has been used in production bicycles for over 20 years and if properly maintained and cared for, is just as viable a frame material as steel or aluminum. Since cycling (particularly racing) can be an inherently dangerous sport, all riders should examine their equipment regularly regardless of material and replace any parts that are worn or damaged.
In closing, we must also note that all carbon fiber is not created equal. There are fringe manufacturers who produce parts that are dangerously light and known for failing. Hyper exotic parts ship with rider weight limits because of their extremely light nature. Knockoff parts that emulate those provided by reputable manufacturers are often for sale on Ebay. Do your homework, purchase appropriate equipment from reputable suppliers and inspect it regularly to check for problems.by