Seat Post cracked
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  1. #1
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    Seat Post cracked

    Just had my '15 Defy Advanced Pro 0 seat post crack going over a railroad track, one I have ridden over the same way numerous times. I weigh about 200 lbs give or take. So, not what I consider a super heavyweight. Bike has 35,000 miles on it.

    I've never heard of something like this happening to anybody and I have a lot of cycling friends.

    Wondering if any other Defy owners have run into this happening or even on other brands.

    Giant's decision to use a proprietary seat post is making it more difficult to easily replace it.

    If I don't get any responses in the Giant Forum, I guess I will try a different category and risk CX's wrath if it's not an appropriate choice.


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    P1010187.JPGP1010188.JPG

  2. #2
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    You weigh 200lbs.

    Yes; that qualifies as a "super heavyweight". Combine that with a carbon fiber post and the shock of riding over anything, including train tracks, and expect your seatpost to fail.

    I have a 160lb. cycling friend who could feel his carbon fiber Ritchey seatpost flex. He was so unnerved by it, he swapped it out for an aluminum post.

    Unless Giant makes a Defy seatpost in aluminum or an adapter to convert the seat tube to a conventional post, there's little you can do.

  3. #3
    What the what???
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    A 2015 with 35,000 miles on it? What's that line from Indiana Jones: "It's not the age, it's the mileage..." Your bike may only be 4 years old, but you got a lot of use out of it.
    The Law of Headwinds states: If the ride out is easy you better leave something in the tank for the turn...

  4. #4
    RoadBikeReview Member
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    Quote Originally Posted by Opus51569 View Post
    A 2015 with 35,000 miles on it? What's that line from Indiana Jones: "It's not the age, it's the mileage..." Your bike may only be 4 years old, but you got a lot of use out of it.
    Not exactly complaining about it's failure as it's been ridden a lot in 4 years. I just never heard or seen of a seat post cracking like that. Hoping to hear how often it happens.

    Appreciate your response.

  5. #5
    Cleavage Of The Tetons
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    Two words:
    Fatigue cycles

  6. #6
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    Quote Originally Posted by Rogus View Post
    Hoping to hear how often it happens.
    I weigh 135lbs. and had something similar happen with an aluminum post. I can't recall if it cracked, but the post head loosened on the shaft and spun around loosely. After that, I only purchase one-piece seatposts.

  7. #7
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    I don't know how even Clydes break all the stuff I see here...handle bars, seat posts, spokes.

    220lb and while I try to avoid potholes and major obstructions, everyone occasionally hits stuff. Never even had a pinch flat.

    ...actually, one pinch flat years ago on my dual suspension MTB hammering down a trail full of baseball and grapefruit size stones. I was still surprised it didn't soak up the hit. Front tire.

  8. #8
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    I had a Defy for 5 yrs (weighed about 200lbs when I first bought it) and then a Propel SL and a TCR - havenít had that happen to any of them. I would chalk it up to use and fatigue buy a new post and move on -thankfully you didnít get hurt.

  9. #9
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    What he said.

  10. #10
    RoadBikeReview Member
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    Appreciate the responses. I am aware of material fatigue. Wasn't asking why it happened, but hoping to find out if it had happened to anybody else. I know manufacturers forums don't get much traffic, but so far no reports of it happening except to me. Maybe a bigger sampling can be obtained in components. Just trying to satisfy my curiosity about seat post failure

  11. #11
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    i think you will be heard pressed to find anyone with 35,000 miles on their 4 year old bike to compare to
    Mike
    Toronto, Ontario, Canada
    2016 Scott Solace 10 Disc
    2017 Diamondback Haanjo Trail Carbon
    2017 Trek Farley 9.6
    2017 Giant Trance Advanced 1

  12. #12
    RoadBikeReview Member
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    Quote Originally Posted by Swerny View Post
    i think you will be heard pressed to find anyone with 35,000 miles on their 4 year old bike to compare to
    Does it make a difference what time frame 35K miles is put on the seat post? It's the same amount of riding, just done in shorter time frame than most seem to do.

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