How Long Does Carbon Fiber Last?

By Jim Langley

This column idea comes from RBR reader Michael Leven, who wrote:

“Since most people who read the newsletter probably ride carbon frames, forks, seatposts and/or wheels, I’m wondering how often they replace these carbon components?

For example, how often do you replace your carbon fork, your carbon handlebars, your carbon seatpost? And should you be concerned about failures on your carbon frame?

I’m asking because over the years I got the idea carbon frames and components needed replacement through word of mouth and reading maintenance books. I even know a randonneur who replaces his fork every three years. What do you recommend?”

Cycling is hard on equipment

Mike’s question is actually an age-old cycling concern. Even in the earliest days of bicycling, when our two-wheelers were made of heavy-duty iron and wood, stuff broke from use and abuse and crashes.

So, it isn’t really accurate to single out carbon as failure-prone, or requiring special treatment, such as replacing components just to be safe. Riders in the past did the same thing with steel, aluminum and titanium components. Especially those pummeled by the monster quads of professional riders.

In fact, one of the biggest debates when the best frames were made of steel, was whether or not the material’s performance changed over the years and miles of riding. While metallurgists said that myth was a bunch of hooey, some pros were so sure frames worsened with use, that they insisted on new ones every couple of seasons.

For more average roadies, like myself – and most of the customers of the bike shops I wrenched at – frame, fork and component failures were primarily caused by some type of abuse, mainly crashing, dropping the bike or running it into the garage when it was on the car roof rack.

Frames and components can fail from incorrect assembly, such as combining parts not made for each other, overtightening or scratching or gouging a part with another one during assembly, for example. This can lead to the piece failing many miles later when the small scratch turns into a crack and then the part breaks. One of my most painful crashes happened this way, when a small cut in my carbon fork (found afterward) caused it to break and hurl me to the pavement.

Maintenance and inspection

For all bicycles and components, whether they’re carbon, titanium, aluminum or steel – you should pay attention to their condition. If you ride regularly, at least twice a year, clean your bicycle and components thoroughly so that you remove any dirt and grime.

Then, just as thoroughly, go over your frame, fork and all components looking for any signs of damage, wear and tear. It should go without saying that you should do this after any bike crash, too.

It’s best to remove the wheels first. That way you can look closely at the frame dropouts (a common frame/fork failure point), and scrutinize inside the fork and behind the bottom bracket area and up around the rear brake. Don’t forget to check your seatpost, seat and the seatpost binder area on the frame.

What you’re looking for is signs of damage, or for steel and aluminum parts, corrosion. On frame and fork tubes and structural parts of components, look for those scratches or gouges I mentioned from a crash or impact with something (even if a bike just falls over when parked, it can strike something such that a component is damaged).

Look closely where things are clamped, such as the stem, handlebar, seatpost, saddle rails and wheel quick releases. This is where things are held tightly and also where a great deal of force is concentrated when you’re riding. If you see any signs of wear and tear, such as dark marks on the metal that you can’t wipe clean, make sure it’s not a hidden failure point. To do this, loosen and move the part to inspect that suspect area and ensure it’s still sound.

Any parts showing signs of wear and tear like this should be replaced. Besides wear marks, look for bends, too. Carbon components won’t bend, but metal can, and if it does, the part should be replaced.

Back to the subject of carbon

But, let’s get back to Mike’s specific question about carbon frames and components and whether they should routinely be replaced. It’s a tough one to answer definitively, because, like Mike and his friend, you may read that your component should be replaced every few years. And who should know better than the company that made the part?

Or you might deduce that because a particular carbon bicycle only carries a 5-year warranty, the carbon might change and be less reliable after that. Or maybe you’ve seen the seemingly endless recalls for carbon cycling frames, forks and components. They certainly don’t build our confidence in carbon.

So, what I recommend is to do what you feel is best. If you’re worried that your carbon frame, fork or component is going to fail, it’s going to be hard to enjoy riding. Even if an expert tells you that there’s no need to worry, you may still worry. If that’s you, you need to do whatever it takes to feel safe, and I wouldn’t try to talk you out of replacing your carbon.

However, what I do is follow the same rules for frame, fork and component replacement I’ve always followed, which is, if it isn’t damaged, I keep riding it. I never experienced changes in the performance of those classic steel frames back in the day, and I have never had a carbon frame or component fail that I didn’t first damage in some way.

I do keep my carbon clean and inspect it carefully. I read and follow the assembly instructions, too. I also use torque wrenches for tightening to ensure things are never too tight, which is one way to cause carbon to fail. But I do not routinely replace components.

If I was considering purchasing a new carbon component and read that it had to be replaced in a few years, I would find one that didn’t carry such a warning.

Carbon is still a bit of a mystery

Summing up, I actually have an 1886 steel bicycle that I still ride sometimes. Every time I climb atop its giant front wheel, I wonder if today might be the day its 129-year-old steel handlebars will snap. But, I’ve been doing that all 30 years I’ve owned it, and they’re still hanging in there.

Will these carbon bikes and parts we’re riding today still be going strong in some future 2116 edition of a L’Eroica vintage bike ride? I don’t know if anyone can answer that about carbon, because it’s still too new. Carbon is a thread made into a fabric-like material. This material is saturated in resin, a type of glue. Then, it’s formed and cured under pressure into a superlight and ultra-strong bicycle frame, fork or component. What has yet to be shown is whether or not the cured fabric and resin can be broken down over time.

But I can say from my experience so far, which goes back to the earliest carbon bicycles of the late 1970s, that it’s performed amazingly well and has proven very durable when carefully used and cared for. So, I clean it and maintain it and inspect it, and keep riding it. And I only replace things when they’re damaged. That’s what I recommend – unless you’re worried. And then, I say go ahead and do what it takes to feel safe and enjoy riding.