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  • I bought a frame on ebay which has a seatpost clamp like that of Vitus/Alan in that it uses grub screws from the back. Its also a 25mm seatpost.
    Now, it came with a seatpost, not original, its a kalloy one but the previous owner has had the grub screw just screwed into the post so the screw is pushing up against the post. It appears to hold my weight fairly well but I'm guessing the original seatpost would have had holes in it for the screws.
    Should I find a correct seatpost?
    Should I drill the seatpost?
    Should I HTFU and ride it as is?
    I'm 65kg give or take a pizza
    What we reckoning

  • What we reckoning

    Don't fit a carbon post :-)

    Set screws have been used to retain circular things in holes pretty much since the invention of threaded fasteners, and people are still doing it because it works. There are tarty ways to make it a more elegant method (flats on the shaft, separate thrust pads between the screw and the shaft), but a simple single flat point set screw can take a surprising large amount of both axial and torsional load to shift. Most of the friction actually comes from the cylindrical contact between shaft and bore, which will be over about 270°; the set screw just pulls a small section of the bore away from the shaft in order to create the necessary hoop stress to be reacted by radial pressure of the bore on the shaft.

  • I should just start PMing you in the future. Cheers
    On another unrelated note, I know its half way through the year now so I'm talking about January time, is there any point in buying a race license or should I just find some events that don't require one so I can have a go?
    I want to try a few different types of event to see which I like more, short TTs, crits, road circuit etc

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