Sanding a carbon seat post?

Midnight Poacher
Midnight Poacher Posts: 12
edited January 2015 in Workshop
Hi all,
I wonder if you could all give me some words of wisdom?
I got a Hylix carbon seat post for Christmas and am having problems with the fit on my Focus Cayo. Its a 27.2 post but it is seriously tight getting it in, to the point where i dont need to do up the clamp and i get no slippage! I have misplaced my digital vernier so cannot be sure on the exact size but i presume its larger than the one i removed.
So, my question is do you think it would be okay to sand down the gel coat a fraction?
Thanks so much for any constructive help.

Comments

  • Monty Dog
    Monty Dog Posts: 20,614
    Firstly, check whether your frame has an aluminium sleeve in the seat-tube as it may be down to aluminium surface corrosion that you have a tight fit. Try sandpaper down the seat-tube first if that's the problem. OK to sand a seatpost, but it could look rubbish.
    Make mine an Italian, with Campagnolo on the side..
  • desweller
    desweller Posts: 5,175
    Is the clamp already on the bike when you try to fit the post?

    The reason I ask is, on my Genesis the paint is quite thick; consequently the clamp nips the seat tube up a wee bit when it's fitted and I can't get the post into the tube.
    - - - - - - - - - -
    On Strava.{/url}
  • Midnight Poacher
    Midnight Poacher Posts: 12
    Thanks for the replies.
    Yes it has an aluminium sleeve but no corrosion as it has not even turned a wheel since i bought it.
    Fitting with or without a clamp makes no difference either.
    Upon closer inspection there is a very slight ridge line running down the first 4 inches, can i cut this off as i dont need it that long of should i sand it out?
  • Midnight Poacher
    Midnight Poacher Posts: 12
    Okay, gave it a good bit of wrist action with some 400 grit and it slides in nicely now. Thanks all. :D
  • chrisw12
    chrisw12 Posts: 1,246
    ...waiting for follow up post, 'my seatpost is slipping, what shall I do' :D
  • crikey
    crikey Posts: 362
    If you sand the carbon post you expose the carbon fibres.
    Carbon fibres plus aluminium = galvanic corrosion.
    Galvanic corrosion = very stuck seat post.

    The clear coat is there to protect the carbon fibres and to reduce the incidence of galvanic corrosion when the carbon is in contact with aluminium. Sanding the sleeve is a better idea, but leaving it all alone is even better. A tight fit is not a problem.

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