Triban 3 - loose seatpost?

Manc33
Manc33 Posts: 2,157
edited November 2014 in Workshop
My Triban 3 seatpost (29.8mm) is pretty loose in the frame, the seatpost is original to the bike.

After buying a 29.8mm shim (to use a 27.2mm post), I noticed the shim also is as loose as the seatpost was.

So it might be the frame's seat tube thats oversized? The thing is, 29.8mm is a rare and strange sizing. Maybe its just that the seat tube is really a 30.8? This would make 0.5mm of wiggle each side, it probably feels that much.

If anyone else here has a Triban 3, just how much wiggle is there? I read somewhere seatposts have to be tight. Is it even safe?

Comments

  • imposter2.0
    imposter2.0 Posts: 12,028
    Obviously seatposts have to be tight - if they aren't, they will not hold the saddle up. I'm not really clear on what you are asking though - when the clamp is tight, the post should not move.
  • gozzy
    gozzy Posts: 640
    I reckon I'm on fairly safe ground saying that bike manufacturers know what size seatpost to sell with their bikes and it would be pretty well documented if somewhere like Decathlon had started knocking out the wrong size posts.

    The logical conclusions are either your clamp is knackered or your frame is knackered.
  • darkhairedlord
    darkhairedlord Posts: 7,180
    you may have damaged it by constantly trying out bad parts from aliexpress and bad ideas from cloud cuckoo-land.
  • Manc33
    Manc33 Posts: 2,157
    darkhairedlord wrote:
    you may have damaged it by constantly trying out bad parts from aliexpress and bad ideas from cloud cuckoo-land.

    If I had damaged it I wouldn't be posting asking why it doesn't fit. Also, I don't think its possible to damage a seat tube in such a way that it ends up coming out exactly the same diameter all the way down it.
  • imposter2.0
    imposter2.0 Posts: 12,028
    Manc33 wrote:
    Also, I don't think its possible to damage a seat tube in such a way that it ends up coming out exactly the same diameter all the way down it.

    Again, I'm not sure precisely what you mean by this. Assuming an aluminium or steel frame, most seat tubes have a constant internal diameter. There may be some exceptions to that rule, but the Triban 3 ain't one of them...
  • Manc33
    Manc33 Posts: 2,157
    I mean the seatpost doesn't go in the seat tube nice and tight like it has with every other bike I have ever owned, it was like that straight from Decathlon and isn't like that because of anything I have done. If it was, why would I be posting?
  • imposter2.0
    imposter2.0 Posts: 12,028
    Can you - or can you not - secure the seatpost by tightening the clamp?
  • darkhairedlord
    darkhairedlord Posts: 7,180
    Imposter wrote:
    Can you - or can you not - secure the seatpost by tightening the clamp?

    only with his ali-express torque wrench, which is very accurate! However, everything he tightens must be rubbish as it keeps breaking :shock:
  • Manc33
    Manc33 Posts: 2,157
    Imposter wrote:
    Can you - or can you not - secure the seatpost by tightening the clamp?

    I can but I don't know if that is safe or not. Its meant to be tight, not loose. I don't know, no one has said "Oh loads are like that you'll be fine" or whatever and I have never rode around on a loose one in my life, until now.
  • dinyull
    dinyull Posts: 2,979
    If you can tighten it, and secure it then it will be tight and not loose.

    How is it loose, does it slip, wobble - what?
  • desweller
    desweller Posts: 5,175
    It'll be fine. If the clamp secures it well enough that it doesn't slip then you're away.
    - - - - - - - - - -
    On Strava.{/url}
  • imposter2.0
    imposter2.0 Posts: 12,028
    Manc33 wrote:
    Imposter wrote:
    Can you - or can you not - secure the seatpost by tightening the clamp?

    I can but I don't know if that is safe or not. Its meant to be tight, not loose. I don't know, no one has said "Oh loads are like that you'll be fine" or whatever and I have never rode around on a loose one in my life, until now.

    You're not making any sense - first you say you can tighten it, then you say it is loose. Does the saddle move when you are riding - YES or NO..??
  • Manc33
    Manc33 Posts: 2,157
    Before tightening the clamp on the seat tube, when the seatpost is inserted, it is pretty loose.

    This rephrasing might clear things up.

    Yep, if I tighten the clamp it doesn't slip, but inside the seat tube - we all know... its loose. There's probably 0.5mm of play around the tube, shocking. :P I've never had one like that, all other bikes I have owned, the seatpost needed a certain amount of twisting into the seat tube to get it in. :oops: This is a "sausage down a corridor" situation. Don't ban me for that.
  • imposter2.0
    imposter2.0 Posts: 12,028
    So you are complaining that your seatpost moves when your clamp is undone, but not when the clamp is tight. You truly are a unique individual...
This discussion has been closed.

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