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When To Get Your Bike Frame Checked for Damage

September 22, 2021 0 Comments

Close-up of a rear bicycle cassette and chainstay

After a bad crash, it’s often fairly obvious that your bike needs some work. Certain accidents do enough damage that you’ve got no choice but to take your bike to a mechanic to get some repairs done.

But what about when it’s not so obvious? After a little bump here or a minor fall there, your bike looks fine. Surely it’s safe to ride, isn’t it?

Not always. Many bike frames these days — even the best ones — can be easily damaged in significant ways. This damage can come from a simple fall, and it may not be apparent to the untrained eye. Longtime cycling coach Darryl MacKenzie has some insights about why that is, why it’s dangerous, and what to do after a bike accident. Spoiler alert: It’s more often than you think.

The 4 Types of Bike Frames

To understand why this can be an issue, it’s important to know what kind of materials you’re dealing with on your bike frame. Almost all bikes are made from one of four things: steel, aluminum, titanium or carbon fiber.

Steel

This was more common in bikes 50 years ago. As manufacturers used to say, “steel is real.” They meant it was strong, sturdy and reliable. It was inexpensive to manufacture, but it had a major downside: rust. That’s why you don’t see it used on many bikes anymore.

Aluminum

Steel eventually gave way to aluminum as a go-to for bike frames in the ‘80s, and for good reason. It’s very cheap to manufacture. It’s also light and stiff, giving a sense of agility and responsiveness to your bike as you ride. But that’s also its downfall — that stiffness and lightness mean it will transmit road vibrations easily, making it tiresome for long rides. Still, It’s a common material in less expensive bike frames these days.

Titanium

Thirty years ago, titanium was the metal of choice for high-end, custom bikes. It’s light, stiff and incredibly strong. When Coach Darryl bought his first titanium bicycle in the ‘90s, the salesman told him he’d never need another bike. And, even though he’s bought many other bikes over the years, he still has that same titanium bike today. It was even strong enough that when Darryl hit the bike against his garage while it was on top of his car, it was his car roof that bent, not his bike.

Despite its strength and reliability, though, titanium isn’t practical for most bicycles. The manufacturing process makes it too expensive for most riders. Today, only a few manufacturers specialize in using titanium.

Carbon Fiber

Nowadays, carbon fiber is the material of choice for high-end bicycles — the kind most serious riders use on the road. It’s a composite material composed of many thin carbon filaments, bound together by a type of resin. It’s much stronger and stiffer than steel and extremely lightweight, yet easy to shape during manufacturing. Therefore, of the four types of bike frames, carbon fiber is most ideal for the aerodynamic designs common in today’s road bikes.

Despite its strength, Darryl notes, carbon fiber has an Achilles’ heel: It’s incredibly weak against force that comes from a different direction than it was made to support. For a bicycle, that means it’s spectacular for supporting bike and rider, but not so good at holding up against impact from the side.

Why Damaged Carbon Fiber Is So Dangerous

Most cyclists are riding on carbon fiber frames, and those frames are ideal for all the reasons we’ve mentioned. But most cyclists probably aren’t aware of carbon fiber’s weaknesses, so they don’t look out for damage or know what to do after a bike accident.

The problem is that this damage can happen quite easily — and it may not be obvious when it does. We’ve written elsewhere about how even a simple fall while your bike is resting can damage the structural integrity of your frame. That’s not only because it hits the carbon fiber in its weak spot, but also because your bike frame has some particularly narrow sections in the chainstay and seatstay, the triangles that run from your rear cassette to the seat post and bottom bracket.

One friend of Darryl’s leaned his bike against a car only to have it fall over and hit the chainstay on a parking block. What he thought was just paint chipping was actually strands of carbon fiber sticking out from his frame. Had he ridden the bike, the chainstay may well have snapped right in half.

Another cyclist that Darryl knew wasn’t so lucky. Despite his mechanic’s advice not to ride his bike after a crash, he decided to go for it. The carbon-fiber tube that had been damaged gave out, and he was killed in the crash that followed.

What To Do After a Bike Accident

Does that mean that to avoid a similar tragedy you have to replace your bike after every accident, no matter how minor? No, but it does mean that you should have your bike checked out by a mechanic.

Any time the frame has taken a blow from the side — even a small one — it’s a good idea to get a professional opinion before you ride it again. If you have the option, it’s best to take it to a dealer for your bike’s specific brand. But any good mechanic should be able to examine the damage and tell you if the carbon fiber has been compromised.

The bottom line is this: If your bike fell over or was in a crash, have it checked. Even if everything looks fine, it’s easy to miss damage that can seriously endanger you on your next ride. Your health — and possibly even your life — are worth the minor inconvenience.

Look for more insights from Coach Darryl over at his website.

Photo by Andrew Seaman on Unsplash