I have a 1 year old BMC Roadracer frame, and for the last few months bubbles are appearing under the clear coat. Slowly, the number and size of the bubbles is increasing, and at some places the bubbles push through the cleat coat, and can be easily felt. At first I though it was grime or sweat or something, but the bubbles sit under the clear coat.

click here for image

click here for image

They can be a bit tricky to spot, but they can be found all over the frame.

I returned my frame to the dealer, and they sent pictures to BMC to hear what they have to say. According to BMC, the bubbles are formed within the carbon glue / epoxy in a reaction to UV rays. They say it's purely cosmetically and is harmless. They don't see this as a warranty case. The best my dealer could do is a extension of the warranty on the paint / clear coat to 5 years.

I can't say I'm satisfied by this. UV rays damaging the epoxy doesn't exactly reassure me, and can't be conducive for the structural integrity of the frame. Furthermore, shouldn't the clear coat protect the epoxy from UV?

Should I demand a replacement frame? I don't feel that these bubbles are 'normal' and 'nothing to worry about'.

I wouldn't worry about it. It looks purely cosmetic and tbh I can hardly even see them in the photos.

I wouldn't accept this period! You payed good money and have the wright to a product who is without cosmetic defects. It is a defect and needs to be fixed one way or another. It's time for manufacturer to stand behind their products. I would take it as far as possible.

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Pfeiffer's Rennrad Camp and Cycling Coach
Independent HED Wheels/Powertap Dealer

maybe they are bubbles in the clear itself and u could wetsand them with like 1500 grit paper

Specialized frames, stems and seatposts used to have the same problem. Maybe they still do.

Well i dont think their explaination is right, as this is a commom problem with many manufcaturers. Its caused by residual mold release agent left on the frame when it is cleared. It eventually causes the clear to seperate from the carbon, and so you get little air pockets in between.

You'll find them to some degree on any molded frame. Some are worse than others, but it is purely cosmetic in any case.

I've got only one that's visible, 5mm oval shaped one on the side of the top tube. BMC told me the same thing, got the local dealer to assist me. The dealer offered to cover for a cosmetic job by a service centre locally, to buff away the clear coat layer and then redo it. I was somewhat concerned that the result might look worse, (and the wait for the job to start/finish should be quite long too), and decided to let things stay as it is. That was 3 years ago...

There is the answer. I wouldn't fuss over it but that's just me. All they would do is sand and clear. Mold release or dust is the cause. My Ridley helium has some imperfections in the clear from dust.

Sand the whole frame! Gotta be a couple of free grams to save!

this is a high end bike, would you accept this happening to your high end car? if yes, ignore. if no, make some noise.

I have seen this on two of my frames and one seatpost and have gotten every piece waranted. Was told it was only a finish problem though.

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Technical editor at Cykelmagasinet Denmark

My Simplon Pavo II

+1

*f##k* the company's who don't stand behind their products!

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Pfeiffer's Rennrad Camp and Cycling Coach
Independent HED Wheels/Powertap Dealer

Just checked out bmc. Yep a huge bubble smack middle of top tube. I was able to crack the bubble apart. It seems this is a problem of bmcs.

The minute I started to demand a proper solution for this problem, the dealer offered to return my money. I'm happy with the outcome, but I will not be buying BMC again!

BMC has a great warrenty.

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Storck Fenomalist 6.3kg.
BMC Teammachine SLR01