Norm asked,
>So the question is how undersized is too much? Mine is a 26.2 that is
>undersized by 0.1 mm. Given
> that this is most likely to be used in a Cinelli with a sleeved seat tube,
> how risky is it.
Norm, It would depend on the interface between the frame and the post and you won't know until you trial fit the two. I learned years ago that just because a post has 27.2 or 26.2 stamped in it, that doesn't mean it will measure as such. Tolerances you know...
If you put the post in your newly acquired Cinelli and it is loose, that's no good and asking for trouble. If slips in with a bit of friction that should be fine,,, unless!! you see that the seat tube lug shows signs of being over-tightened and squashed already,,, It's all by feel and common sense.
On many occasions I've had riders bring in bikes with slipping seat posts that were supposed to be the right size. The post might "mike" a little under size, and maybe the seat tube had been reamed a little over size, not good. We could possibly ream to the next seat post size up, or what I usually do is mark the ride height of the post on the edge of the seat lug with a sharpie. Then I chuck the post up in the lathe and knurl it a shade below the sharpie line, but in the clamping zone of the lug.
Knurling brings the size of the post up, and it also gives it "tooth". Both of these changes aid seat post tightening and allow you to use less clamping pressure to keep a post in the right place. I should add that this works on alu. alloy posts best. Chromed steel will ruin the knurls, and we're not allowed to talk about the other seat post materials on this list.:~))
When you find your Cinelli, do a trial fit with your seat post, any questions or concerns don't hesitate to contact me or drive it down and we'll have a look.
I hope to be in Monson on Sunday, (I love Jim's show),,, but I have a few things to get out of the way first. I'll look for you if I'm there.
peter weigle lyme, ct.
Hi Peter,
>
> Your comment about the gnarled then polished seat post caught my
> attention. I have one exactly as you described. So the question is how
> undersized is too much? Mine is a 26.2 that is undersized by 0.1 mm. Given
> that this is most likely to be used in a Cinelli with a sleeved seat tube,
> how risky is it.
>
> Will you be at Monson on Sunday?
>
> Norm