Seatpost Issues

mroli
mroli Posts: 3,622
edited January 2013 in Workshop
So I have got this Dedacciai pista frame: http://www.wiggle.co.uk/dedacciai-pista-2011/
As you can see - seatpost size is 27.2. I have this seatpost:http://www.wiggle.co.uk/deda-rs01-black-seat-post-black/in a 27.2.

I get a little bit of assembly paste, put the seatpost in and stop after about 1cm. I put the saddle on the seatpost and try and wiggle it in, I try and try and try and manage to finally get it in to about the min level insertion point, but no further. I remove seatpost, grease it up and try again. Again, a struggle to get it into that min level point and not further. The frame is notably hot from my exertion.

Any tips anyone? I guess I could cut the seatpost so the minimum level is right for my saddle height, but is there an easier way of sorting this (that doesn't involve heating the frame and freezing the seatpost for example!)

Ta

Comments

  • drlodge
    drlodge Posts: 4,826
    I've got the same seat post, goes easily into my 531c frame which is defo 27.2mm. Sounds like your frame might be 27.0 but the web site does say 27.2mm.

    If its really only going in 1cm before it gets tight, something is wrong. Have you measured the seat post size (in case its too large) and the frame size to see which is one is out? One of them has to be not 27.2mm.
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  • Measure the internal diameter of the tube with some calipers, sounds like you might need a 27.0mm seat pin.
  • mroli
    mroli Posts: 3,622
    Ok - will dig the calipers out tomorrow and have a look. I thought Deda post & frame would be compatible!!!
  • nicklouse
    nicklouse Posts: 50,675
    or there could be some crap in the frame.

    has it ever had a seat post in it?

    have you checked the seat post size?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • mroli
    mroli Posts: 3,622
    Brand new frame. Never had a seat post in it. Seatpost says 27.2 on it. Spec from wiggle (as above) says 27.2 seatpost.

    Will get the calipers out tonight.

    Good forum stuff here: http://forum.ctc.org.uk/viewtopic.php?f=5&t=44266
  • nicklouse
    nicklouse Posts: 50,675
    before doing that get a torch out.

    and calipers are very poor for measuring seat tubes. ok for measuring seat posts though
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Tolerances...
    if your seatpost was bare alloy, you could sand it a bit and then polish it, but as it is anodised, you can't without rendering it ugly... obviously you can do the same with the inner of the seat tube, but it is a much more demanding job... I've done both and the seatpost is definitively doable. Otherwise get a cheap 12 pounds Kalloy one... they are actually as good as Super Record ones

    Besides, fitting an anodised seatpost on a steel frame is looking for trouble... it will for sure end up seized... definitively get a polished one, or polish yours, if you can be bothered
    left the forum March 2023
  • Monty Dog
    Monty Dog Posts: 20,614
    The frame may not have been properly finished i.e. has a 27.2mm reamer been run down the seattube?

    Ugo, don't understand your comment regarding anodised seatposts and steel - all my engineering materials experience was that we anodised parts to minimise the effects of galvanic corrosion. Bare aluminium alloy on steel is never a good combination.
    Make mine an Italian, with Campagnolo on the side..
  • Monty Dog wrote:
    The frame may not have been properly finished i.e. has a 27.2mm reamer been run down the seattube?

    Ugo, don't understand your comment regarding anodised seatposts and steel - all my engineering materials experience was that we anodised parts to minimise the effects of galvanic corrosion. Bare aluminium alloy on steel is never a good combination.

    Yes, but in my experience you can happily mix an alloy seat post with a steel frame, but if you try with a black anodised seat post, you can be sure it will be stuck. Not sure it's corrosion of the aluminium alloy that keeps them there, rather steel corrosion, combined with the friction of an anodised metal tube, or galling or whatever...
    left the forum March 2023
  • on-yer-bike
    on-yer-bike Posts: 2,974
    Sounds obvious but is there a build up of paint in the top of the seat tube? I hand to use fine wet and dry to remove this on my steel frame in order to get the seat post in.
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  • keef66
    keef66 Posts: 13,123
    Have you tried it without any assembly paste? Does it fit when both seat tube and seat post are clean / dry?

    A thin coating of grease will offer less resistance than assembly paste.
  • andyrr
    andyrr Posts: 1,822
    Wouldn't feel the need for assembly paste for anything other than carbon components. Metal I'd use grease and, if it then gets used in damp/grotty weather it's a good idea to remove it regularly and clean/lightly re-grease.
    The carbon assembly paste is, I thought, to help minimise the amount of torque that the component has to be tightened to and as carbon parts are particularly susceptible to over-torquing, that's qhy the stuff is used in that situation. To help with slipping a metal seat post down the frame I'd use a grease to help with the insertion (oo-er) and to stop it seizing.
  • keef66
    keef66 Posts: 13,123
    That's what I was thinking. The little gritty particles in the paste do take up some space. My carbon post kept slipping into my alloy frame, so I now use assembly paste which has solved the problem. However it feels as if the post is much harder to insert into the frame.
  • mroli
    mroli Posts: 3,622
    Tried assembly paste first (I thought it'd help with the seizing issue), then wiped it all off (because of the above thinking), tried it "dry" and then tried it with grease. No noticeable difference with any of the above. No paint in the frame. Have a 27.0 seatpost on the way, my LBS will ream the frame for me, Wiggle are looking into it and I will try and get the calipers out tonight. Thanks for all the suggestions above - will keep trying!

    Ugo, note the anodizing/seizing point, I would ensure that I removed and re-greased the post often. Besides, unless I grow/shrink, can't see it being a problem if it does seize!
  • crankycrank
    crankycrank Posts: 1,830
    Monty Dog wrote:
    The frame may not have been properly finished i.e. has a 27.2mm reamer been run down the seattube?
    +1. Not uncommon for new steel frames to need a good seatube reaming. I never could understand the practice of making a skillfully crafted and expensive frame and then sending it out needing to be reamed, faced, and threads chased by the owner or LBS. :shock:
  • I know this is pretty old, but I got one of these frames and have the same issue. It's getting reamed today. I read something online about how the italian frame builders box the frames up and send 'em out before the paint is fully cured, so they expect the bike shop to chase/face and ream everything necessary. Except that it's wiggle and they've not bothered. I'll be honest, I'd be fuming if I'd paid RRP on this! Also, have you now got it built up after reaming? How does it look!?
    Ribble Audax - FCN 5
    Dedacciai Pista - FCN 3