How do you choose an appropriate seat post length?

Discussion in 'Cycling Equipment' started by CyclinYooper, Jan 22, 2011.

  1. CyclinYooper

    CyclinYooper New Member

    Joined:
    Jan 9, 2011
    Messages:
    77
    Likes Received:
    1
    I've currently got a cheap 31.6x300mm seat post on my bike. I'm looking at upgrading to a 3T Dorico Team seatpost (mostly because it's affordable, pretty light, and has the 25mm offset that I need). Anyway, they come in 280mm and 350mm. Can I use the 280mm? Or do I have to use the 350mm?

    On my current setup, about 130mm is exposed above my seatpost clamp (leaving 170 in the tube).

    Thanks, Scott
     
    Tags:


  2. swampy1970

    swampy1970 Well-Known Member

    Joined:
    Feb 3, 2008
    Messages:
    10,057
    Likes Received:
    185
    Assuming the seatpost clamps are not all that different in height then you can assume you'll still have about 130mm exposed above the seatpost clamp, which for the 280mm seatpost will leave more than that (130mm) in the seat tube... which will be plenty. Normally, expect to leave about a 1/3 of the post in the seattube - with most of that preferably below the point where the seat and toptubes meet.

    As you can see the MIN point is about a 1/3 of the way up the post.

    [​IMG]
     
  3. Peter@vecchios

    [email protected] New Member

    Joined:
    Dec 30, 2007
    Messages:
    2,111
    Likes Received:
    4
    150mm in the tube is plenty. The 280 will be fine.
     
  4. 531Aussie

    531Aussie Well-Known Member

    Joined:
    Apr 11, 2004
    Messages:
    12,606
    Likes Received:
    137
    I dunno about these days, but the old 'rule' I was told was that the bottom of the post had to at least go passed the bottom of the top tube.


    [​IMG]
     
  5. kdelong

    kdelong Well-Known Member

    Joined:
    Dec 14, 2006
    Messages:
    3,477
    Likes Received:
    74
    All but the cheapest seat posts have a minimum insertion mark on them. Don't get one that requires you to ride with the minimum insertion mark above your seat tube clamp. If you get on 3T's website, you will probably find the dimensions of the seat post including the length of the seat post above the minimum insertion mark and see if that works for you.
     
  6. CyclinYooper

    CyclinYooper New Member

    Joined:
    Jan 9, 2011
    Messages:
    77
    Likes Received:
    1
    Thanks for the help guys. I ordered a 280 and I'll give it a shot!

    Scott
     
Loading...
Loading...