I have an On-One Scandal aluminium frame, into which i have put a carbon seatpost. I have been adjusting it to find the right height, and i have noticed that it is getting seriously scratched - see a terrible photo. The scratching isn't deep enough to weaken the seatpost, but it looks ugly.

I have tracked some of the scratching down to the sharp edge around the top of the seat tube, and around the clamp notch (or whatever you call that). I have filed those so that they are smoothly chamfered, and now they don't scratch the seatpost.

However, further down the seat tube, the top tube and seatstay trunk (or whatever you call that - on this frame, the seatstays don't join the seat tube directly, they join on to a short piece of fat tube which then joins the seat tube) join on. Where each joins, there is a small hole in the wall of the seat tube (i suppose these are to ventilate the insides of their respective tubes). These holes have sharp edges, and i believe it is these which are scratching the seatpost.

Has anyone else come across this problem?

The holes are too far down to be able to get a file at them. I've applied some carbon assembly paste around them, and that helps a little (it seems to act as a lubricant when not clamped).

How can i stop my seatpost getting scratched?

  • 8
    I don't think I've ever seen a seatpost that wasn't scratched. Commented Apr 14, 2013 at 23:41
  • But mine is SO BEAUTIFUL! Commented Apr 15, 2013 at 0:12
  • 4
    @Tom: Correct tense here is "was" :(
    – mattnz
    Commented Apr 15, 2013 at 3:20
  • I just tried my smooth,shinny mountain bike seat post in my road bike and if scratched it up so ugly and nasty.now both posts are the same damn thing. :( i know this is caused by the seat tube.
    – user8879
    Commented Dec 27, 2013 at 15:31
  • have you tried spinning a "cylinder hone" in the seat tube? Would have to be a very small one, perhaps for a motorbike or lawnmower engine.
    – Criggie
    Commented Jun 3, 2018 at 0:48

1 Answer 1


Possible solutions:
- Let a bike mechanic ream the seat tube slightly
- Wrap some sanding paper around a broomstick or similar an grind the sharp edges

  • +1 for the sanding paper, looks like a solution that might work.
    – Uooo
    Commented Apr 15, 2013 at 12:43

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