My first post here after lurking some time, but i thought that this must be something for carbon experts like you.
I was out looking at a lovely Look 595 ultra, but the frame have been cut to fit the former user, so if I have to fit it, I'm missing 1-1,5 cm under the stop limit at the seatpost. I have uploaded pictures below to illustrate the seatpost (that have several cuts/lose elements)
I need to tighten the seatpost right under the red spacer ~1cm under the stop.
I weight 65kg (with clothes), so is there any risk that i can damage the frame or seatpost?
Is it a go or no-go?
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I'll leave you to look into it further.
My guess is the strength is proportional to the square of the amount of seatpost in the tube but a mechanical engineer would be able to answer that better.
I think most seatposts recommend about 2.5" of minimum insertion, and I have run them with only about 1" of insertion.
Going 1-1.5 cm below the manufacturer's line seems pretty safe to me because the manufacturer typically includes a very conservative safety factor.
But this is just my opinion, and like all deviations from manufacturer's specs, it is 'At your own risk."
I happen to be a mechanical engineer, but I have applied no analysis whatsoever to this. Only gut feel and experience.
2.5" (6.25cm?) of grab is probably not enough. I have worked with quite a few bike engineers, and they mostly say 7-8 is required.
In fact, a manufacturer I know that uses internally butted seat tube with 2" of grab is having lots of warranty issues. Remember this is in Asia where 65kg dudes are pretty common.
You can find a guy who works with carbon and he will make the seat-tube in height you need. It will be great if you have the piece which was cutted
It should not cost more then 50 euros and here our guy make it so good nobody can find where it was putted together
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