Should I be seriously concerned here?

[thenewguy11]

I was giving my bike a cleaning when I noticed a couple marks which could be cracks or fractures in the carbon chainstays - I'm not really sure. See below.

http://i424.photobucket.com/albums/pp322/ttoth11/2011_05_28_2020.jpg

http://i424.photobucket.com/albums/pp322/ttoth11/2011_05_28_2021-1.jpg

I'm not sure if its just a crack in the clearcoat or something more structural. Any thoughts?

[biker72]

The top photo definitely looks like a crack to me. I’d take it to my LBS and get it checked out.

[godfrey1112000]

Some companies will repair at no cost if you are the original owner as long as

you did not crash in racing, ect .ect. blah blah blah
you know the fine print

sometimes they may even give you a new frame for a small fee

my riding partner got a new Argon for $500 after cracking the frame

kill them with compliments and kindness and you will collect dividends

[biker72]

Most major manufacturers have a lifetime warranty on frames for the original owner.

Where I work, there would be no fee for frame replacement if the bike was purchased there.

[Peter P.]

I doubt a bike shop could determine something that you could yourself.

Lennard Zinn suggests tapping the area with a coin such as a nickel to see if you can hear something that might infer a crack is forming. Compare the suspect area to other sections of the chainstay.

I would suggest painting over the area with a contrasting color of fingernail polish. If that polish cracks as well, you likely have a loose joint.

Or, merely eyeball it after every ride to see if the gap increases. I had a steel frame which was cracking. I marked the ends of the crack with a sharp point magic marker so I could follow the progress of the crack. Worked like a charm.

[Lionel]

I would not ride this without a full check by the manufacturer of the frame.

[Joachim]

I had a steel frame which was cracking. I marked the ends of the crack with a sharp point magic marker so I could follow the progress of the crack. Worked like a charm.


I thought steel is a progressive failure/fatigue while carbon could be catastrophic? Maybe an engineer can chime in.

Disclaimer: I work with tiny chemical molecules and have absolutely no knowledge of metallurgy (except seizing seatposts)

[rice rocket]

Get it checked, but it's possible it's just the paint cracking.

[Black Dog]

Is it a Trek? This looks like paint cracking and is not uncommon with Treks and other brands. Trek even issued a technical bulletin about this. I had a carbon Jamis that did this at most of the joints and look like yours and it was just the paint. I was very worried about it until I looked into it. One way to tell that it is a paint issue is the "cracks" overlap and wrap around to tube. If they are cracks you would see them open up if you put someone on the bike and had them stand on the pedals and also hold the brakes and stand on the pedals.

[oldpotatoe]

I was giving my bike a cleaning when I noticed a couple marks which could be cracks or fractures in the carbon chainstays - I'm not really sure. See below.

http://i424.photobucket.com/albums/pp322/ttoth11/2011_05_28_2020.jpg

http://i424.photobucket.com/albums/pp322/ttoth11/2011_05_28_2021-1.jpg

I'm not sure if its just a crack in the clearcoat or something more structural. Any thoughts?

Warranty that sucker..those are cracks.