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I have a 2010 Gary Fisher Cronus, when I brought the bike in for a tune up this spring the bike shop told me they wouldn't do it because of cracks around the seat post. They pointed out that I had my seat post so high that it wasn't able to give adequate support. I will note that last year I would hear some loud "pops" when going over bumps. I always assumed it was a rock hitting my frame. The shop found the cracks with a light.

I went and bought a longer seat post and I have been riding the bike all season.

Questions: Will my frame fall apart from underneath me? If I can't see the cracks, are they still repairable? Is there an easy way of getting an inventory of the cracks on the frame? At what point is the frame just plane old and I need to tell my wife I need to buy a new one? Finally: Is there a proper way to frame the question so my wife will say "Yes"

The last question was a joke :)

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  • Jeez, is 2010 old? There are specialists out there who offer carbon repair services, I'd recommend speaking to them. And if your wife already knows you have a carbon frame, I reckon you're halfway there! Seriously, bear in mind that when carbon fails, it can do so without warning, so be careful out there.
    – PeteH
    Aug 10, 2014 at 19:58
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    I would ask the shop that found the crack to look for others. Me, if the new tube is now extends lower than the cracks I ride. If the cracks grow I stop riding it. I just checked the seat tubes on all my bikes. And don't tell your wife the cracks are from having the seat too high.
    – paparazzo
    Aug 10, 2014 at 20:20
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    I would say if you know there are cracks, find a carbon specialist and get them to assess the damage and if its repairable / worth repairing. It can't be known if the bike is safe or how it will fail until then. And, for future reference, they do mark the seat post insertion level for a reason.
    – Batman
    Aug 11, 2014 at 5:15

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Riding without enough seat post in the bike is a real problem. Not only do you increase the mechanical advantage of the seat post against the seat tube but you put stress where the bike was probably not designed to take stress. And you are putting stress in the area of the top tube and seat stay.

You state you have been riding with a longer post. Have you monitored the cracks to see if they are growing?

If the cracks are just in the top of the seat tube and have not grown I would ride. I doubt you are going to have the bike shatter under you.

If any crack has moved into the top tube or seat stay then you have a problem.

If the shop refused to work on the bike that is a pretty strong statement.

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I have a similar problem with my MTB and so far, I have ridden several hundred km and the crack remains the same. Good luck.

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    Hi and welcome to bicycles.stackexchange. It's great to hear about your experience,. but we really prefer to have reasoned answers rather than only anecdotes. If you can edit your answer to say how you monitor the cracks and how you'll know when the frame isn't safe to ride that would be great.
    – Móż
    Jan 13, 2016 at 19:56

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