Originally Posted by
cyclintom
https://www.irishtimes.com/sport/oth...ries-1.1879653
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In terms of technology three-time Tour de France winner Greg LeMond was a pioneer. When steel dominated, LeMond rode bikes made of carbon-fibre composites, then an exotic material mostly used by the military.
At this year’s Tour, carbon fibre is the only material used for bikes and it has also replaced aluminium in wheel rims. Strength, weight and design flexibility has ensured the material’s dominance. And its most extreme form, the time-trial bicycle, was on display in Saturday’s 20th stage.
But there’s a catch: unlike steel or aluminium, carbon fibre does not bend in crashes. The bikes and wheels frequently shatter, often hurling riders to the road and, many fear, increasing severity of injuries.
“Anyone in a team who’s being honest with you will tell you how frequently their bikes are breaking; everybody knows,” said Mark Greve, a physician and assistant professor of sports medicine at Brown University who studied injuries to 3,500 competitive cyclists. “Few people in the public appreciate how many bikes a pro team will go through in a season, because they break
.”
Having conquered professionals, who ride frames that retail in the United States for $5,000 (€3,700) to $6,000 with forks, carbon fibre is making its way to increasingly affordable models available to the more casual riders.
A code of silence exists among riders, even retired ones, and mechanics and team officials over the carbon bike and wheel durability. The teams and riders exist, in part, to act as powerful marketing tools for bicycle makers. But when they spoke on the condition they not be identified, their stories emerged. Riders described landing on the top, horizontal tube of the bikes during crashes and ending up on the road after frames collapsed. Even small spills often require a bike change. Mechanics say they sometimes return the shattered remains of frames to manufacturers in bags intended to hold a single bicycle wheel."
When lawyers are lining up you can bet that there's something under those circling vultures:
https://www.atlantainjurylawyer.com/...-injury-o.html
In 2015, the U.S. Department of Transportation published a report that noted pedal-cyclist fatalities had increased by 12 percent year-on-year. Now there could be many reasons for this but bicycle recalls are routinely announced by the Consumer Product Safety Commission (CPSC). The safety agency has recalled millions of bicycles due to cracking frames, breaking forks, faulty chains, failing brakes.
https://theracery.com/blogs/news/is-this-carbon-safe
We are continually told that aluminum and steel are no more safe than carbon fiber. And yet we didn't have people crying about sudden catastrophic failures of steel or aluminum.
It must also be said that you obviously do not appreciate the changes in carbon fiber bikes over the last five years. They have gone from "we don't trust this material so we will overbuild it" to "who cares - racers want the lightest possible". The end result is several people bragging about having bikes with all up weights of 12 lbs.
You can absolutely rely on people who have paid $6,000 for a bike to defend it to the death. And let's hope it doesn't come to that.
Well check this out then
or this
Look, it is not as simple as one is "better" or "stronger" or "more durable" than the other. Fact of the matter is, carbon fiber does not fail more easily than aluminium full stop. First of all, there is the difference between
impact and
fatigue resistance.
Carbon fiber has better
fatigue resistance than aluminium or steel (also depending on design, but generally). So it will last longer under normal conditions in fact, because "fatigue" is a particular material property of metals. Carbon fibers and resin are not metals.
Impact resistance: It depends on the design. Carbon fiber is stronger (more resistant to impact) for the same weight. But if you design it to a lower load or impact limit because of additional weight savings, there is where it can become weaker. You can also design one aluminium frame to be less strong (less resistant to impact) then another for example.
You are also talking about two different things:
crashes versus everyday use. In everyday use, carbon fiber bicycles are totally safe in terms of both impact and fatigue resistance. You will not exceed what the material can handle by going over potholes, etc.
In terms of crashes: you are talking about professional riders in the above article. Multiple crashes occur during a typical race, at 50 kmph. Of course the carbon fiber frames are (potentially) destroyed after a crash like that. Is that really a surprise? Aluminium frames could similarly be bent after an impact (look at the first video of impact testing of aluminium). As a kid, I bent a steel fork on my bicycle crashing it into some stairs for example. Problem is: with steel or aluminum the damage will be more visible apparent, while carbon might have hairline fractures that are difficult to spot with the naked eye. You should get your frame inspected (X-rayed) after a crash. If you are talking about recreational riders: you will crash seldomly (hopefully), and at lower speed if you do crash. But yes, after a crash, it is possible your bike has sustained catastrophic damage.
Bottom line: carbon fiber bikes are totally safe in daily use, and actually have a greater fatigue (not impact) resistance than aluminium (see GCN video for fatigue testing). So if no crashing occurs, carbon is actually SAFER, and will last longer than aluminium.
Impact (crash) resistance is a different matter, and you should have the frame inspected by a professional after a crash. There is no "conspiracy theory" or "omerta" here about carbon fiber bicycles. Everyone with common sense knows that a bicycle can be damaged in a crash. The only "danger" is people potentially being stupid and continuing to ride a carbon frame after a crash without proper inspection. Carbon fiber CAN sustain damage not visible to the naked eye, unlike aluminium or steel (you can't even physically ride a bent frame or fork).
Sadly, people generalize all of these aspects and take them out of context. Steel, aluminum, titanium, carbon fiber, all have their uses in bicycle manufacturing.