Just been cleaning my Canondale CAAD8 and noticed these cracks in the seat post - they look like cracks in some kind of outer covering and wondering if someone can tell me how much of a problem they are likely to be.

Seatpost crack1

Seatpost crack2

  • Yeah, it's gonna fail. Probably not catastrophically (unless you're in the middle of some sort of dangerous jump at the time), but fairly completely. You can probably delay complete failure a bit (and make any failure a little less sudden) by getting a stainless steel spiral hose clamp at a hardware store and wrapping it around the post, about an inch below the top. Mar 11, 2017 at 19:52
  • 9
    STOP RIDING THAT BIKE NOW! You need a new seat post - one decent pothole and you'll be sitting on the rear wheel or you'll have the remains of the seatpost shaft in your stomach. Check out the cannondale warranty if you want, but that is totally unsafe to ride as is.
    – Criggie
    Mar 11, 2017 at 23:43
  • What Criggie said. I wouldn't ride it. You might return to the saddle after standing, the post might fail and you're going down. While waiting on a warranty replacement, you might visit your lbs for a cheap/temporary replacement.
    – Malarky
    Mar 14, 2017 at 17:42
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    Heh in the last picture - that logo now says "cannonclale"
    – Criggie
    Mar 1, 2019 at 23:43

1 Answer 1


That seat post is made of carbon fiber tube and metal seat mount that plugs into it. The carbon tube is about to split and the inner part you see is the metal plug. It should be replaced immediately and should be a clear warranty case if the bike is new enough.

  • 1
    I am now the proud owner of a new, lighter, seat post. Cannondale's website says components are only guaranteed for one year (the bike is 5 years old) but I may contact them nonetheless.
    – Mr_Thyroid
    Mar 14, 2017 at 21:12

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