Viewing 15 posts - 1 through 15 (of 15 total)
  • 30.6 in a 30.4?????
  • devs
    Free Member

    Anyone tried a 30.6 seatpost in a 30.4 frame such as a Nomad for example? How tight are the tolerances?

    coatesy
    Free Member

    Depends on the tolerances of both, as you’ve said. I’ve seen it done with a 27.4 in a 27.2 before, guess it’s a case of suck it and see.

    TandemJeremy
    Free Member

    if its a bit tight then sanding it down might be enough to get it to fit. beware of getting it stuck tho

    ballsofcottonwool
    Free Member

    In engineering terms a heavy press fit for a 30 mm hole requires a 30.05 mm shaft.

    With a post 0.2mm bigger than the hole it just ain’t gonna fit.

    http://www.mitcalc.com/doc/tolerances/help/en/tolerancestxt.htm

    coatesy
    Free Member

    If only bike manufacterers worked to those tolerances, eh?:)

    ballsofcottonwool
    Free Member

    which ones?

    TandemJeremy
    Free Member

    the tolerances where the difference between 30 and 30.05 is considered relevant. I measured up various seatposts all supposedly the same size and there was at least 0.15mm difference – same with 20 mm axles

    coatesy
    Free Member

    Most of them, especially the lower to mid price ones, I regularly come across frames that look like they’ve been bored out with a rusty drill bit, and seatposts that rattle around like a d**k in a shirtsleeve.

    bassspine
    Free Member

    if the tolerances are against you you get an interference fit. That plus a bit of corrosion, and in a few weeks time you have a one piece frame and seatpost combination…
    I’d maybe try it on a cheap frame, but on something good I’d get the right size post.

    TinMan
    Free Member

    Here Here to sanding it down. Almost guaranteed to corrode in situ once you get it in, but if you never adjust it, what’s the problem. Remember to buy a silver post, cause it’ll look awfully scruffy if you sand down black
    😈

    njee20
    Free Member

    A Nomad’s a 30.9 surely?

    steel4real
    Free Member

    Exactly !

    Where on earth did he find a 30.6 ???

    cynic-al
    Free Member

    you won’t spend £30 to finish a £1700 frame?

    devs
    Free Member

    Blimey! I could have sworn my Nomad was 30.4. I was just looking at those on -one sale carbon seat posts and wondering if a 30.6 would fit. Al, the frame has been finished a long time but the post looks worn. I would replace it if I thought it was worth it but if I ain’t getting a bargain I ain’t getting it! 😀

    devs
    Free Member

    Can’t see any 30.6 posts now. I’m going mad or I dreamt it or something. Beer required I think.

Viewing 15 posts - 1 through 15 (of 15 total)

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