Seat Post cracked

Printable View

  • 05-27-2019
    Rogus
    3 Attachment(s)
    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.


    Attachment 325157

    Attachment 325158Attachment 325159
  • 05-27-2019
    Peter P.
    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.
  • 05-27-2019
    Opus51569
    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.
  • 05-28-2019
    Rogus
    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.
  • 05-28-2019
    rideit
    Two words:
    Fatigue cycles
  • 05-29-2019
    Peter P.
    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.
  • 05-29-2019
    MaxKatt
    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.
  • 06-01-2019
    FasterStronger
    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.
  • 06-07-2019
    Tallboy1959
    What he said.
  • 06-08-2019
    Rogus
    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
  • 07-15-2019
    Swerny
    i think you will be heard pressed to find anyone with 35,000 miles on their 4 year old bike to compare to
  • 07-17-2019
    Rogus
    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.