Can Your Broken Bike Be Repaired?

The Myth: One small crack and your carbon-fiber frame is destined for the landfill.

The Truth: As it turns out, carbon is eminently repairable. A cottage industry of repair specialists now works to save many bikes from the Dumpster.

What is Repairable?

According to Heather Ross, the former frame-repair service manager at Calfee Bicycles, in La Selva Beach, California, most damage can be fixed (like these 25 Simple Bike Repairs every cyclist should know). Calfee has mended more than 6,000 frames since 2003. Shawn Small, of Portland, Oregon-based Ruckus Components, who has fixed more than 200 bikes, agrees. "Pretty much anything can be repaired," he says, noting that the process of layering carbon, compressing the frame, and curing the new material is similar to the way new carbon bikes are made.

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This type of work is not limited to minor damage; the pros can fix tubes snapped through and frames snapped into multiple pieces. Bottom-bracket shells can be replaced; cable stops and front-derailleur braze-ons can be mended.

Repairs can be done on more than frames, too. Some companies will fix wheels as long as the brake track is not damaged. Liability concerns, however, seem to dissuade most companies from working on forks and handlebars.

Beyond repairing damage, the same techniques can be used to add carbon to a frame, for example, to lengthen an integrated seatmast, if you want to sell your frame to a taller friend.

There are some limits, though, especially when carbon dropouts are involved. Calfee doesn't touch carbon dropouts, but its crew can sometimes graft on new ones, along with stays from a compatible donor frame. (Perhaps USA Cycling should include a donor option line on racing licenses, in case of crash damage.)

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How is it Done?

"Technologically, there's nothing about carbon that takes special skill to repair," says Cervelo engineer Damon Rinard (read the Making of a Custom Carbon Fiber Road Bike to learn more). The procedure starts with removal of the damaged carbon. Next, the area surrounding the damage is sanded, tapering toward the missing fibers. New layers of carbon fabric are used to rebuild the affected area, then cured. Finally, the repair is sanded to match the original frame shape.

The greater challenge is restoring the original finish, and quality work can set better jobs apart. Typically, painted frames can be made to look close to what they did when new, for a (sometimes high) price. In other cases the repair is left unpainted, for a battle-worn look.

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How do Repairs Affect Performance Bikes?

Manufacturers carefully tune the stiffness and ride qualities of carbon frames and worry that a repair job would alter those qualities, but such concerns are apparently often unfounded. Calfee engineers painstakingly match the orientation of a frame's original fibers when working on a frame, restoring a bike's character.

Since many repairs replace material but don't add additional carbon, frames usually don't become noticeably heavier. Larger repairs, those that involve reinforcing a tube with foam or placing a support tube inside the affected area, can add some weight, but usually not more than 100 grams, according to our experts.

A properly restored frame will also be just as strong as its unbroken original. One composite engineer at a major bike brand who spoke on the condition of anonymity said he has performed pedal and head-tube fatigue tests on repaired carbon frames and found they passed his company's internal standards. It's even possible a cracked frame can come back stronger if it was damaged in an underengineered area or failed due to a manufacturing defect.

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Drawbacks?

When we spoke with frame and composite engineers at Specialized and Cervelo, we expected them to voice strong objections to the idea of repairing carbon frames. Instead, they support the concept. "In many ways, repaired carbon frames are probably better than repaired metal frames," said Cervelo's Rinard.

"The repair process is really simple, I do it here for employee bikes," said Brad Paquin, a composite engineer at Specialized. "We could certainly perform that sort of repair [for the public], but once you release the frame back to the customer, you've assumed responsibility and liability. When you factor that in, it's safer for us to just [replace] a frame."

Another concern is the resale market. Some fixes are so good they're nearly invisible. That amazing deal on eBay or craigslist? It could be a carbon frame with a substandard fix, and you'd never know. Small, at Ruckus, admits that this is a worry, but not for his service: "We're not concerned about the integrity of the repair, but we are concerned about [someone] selling something to an unsuspecting customer."

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Is Repair for You?

Simple repairs typically cost between $200 and $500. Complicated fixes are more expensive, and recreating the original paint can increase the price dramatically. At a certain point, buying a new frame may be a better investment. If you drive your brand-new Specialized S-Works Venge into your garage door, spending $500 to get it fixed is a great value compared with a new frame for $4,400. But if your frame is aging and you were already thinking about something new, that $500 is probably better applied to something at the shop (Follow this guide on When to Splurge and When to Save on bike gear).

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