joona wrote:
*I think there's no other way to make sure that your seat post doesn't
twist than to just put a bolt through it. . You can check this little
thread of mine where we had a little discussion about this:
'_Improving_seat_clamp_and_post_' (http://tinyurl.com/wwh9)
*

I don't recommend drilling holes through the seatpost or seat tube, but
if you have to then drill at least two diameters below the top of the
seat tube, and don't tighten the bolt enough to crush the tubes. It
should ideally fit the hole well so that the seat tube rotation is
minimal, but have zero crushing force. Using two nuts jambed together
would be better than one nut jambed against the frame.

Do NOT drill the hole near the seat collar. Holes tend to concentrate
stresses, and this is one of the high stress areas for the seat post.
Two diameters below the top of the seat tube and you're well away from
major stress areas of the seat post. The seat tube is still stressed
there, however two diameters down from the top the stresses are
organized well and so the hole won't have as much effect. Drilling the
hole there only reduces the strength of the seat tube by about 50%.

I'd try some other method first, like sanding the seat post and inside
of the seat tube to roughen the surfaces (Plan A), or using a bit of
fine sand between the two to increase the friction (Plan B).


--
cyberbellum - Level 0.5 rider

If I knew what I was doing I wouldn't be in research...
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