Originally Posted by DanRH
I'll try that when I get home from my business trip. I have an aluminum seat post BTW. Thanks!
Again, just so you know... flipping the clamp so the opening isn't aligned with the compression slot in a seat post mast will not increase the clamping force.
As previously noted, it prevents excessive "pinching" at the compression slot which can lead to a damaged carbon seat post. Moving the clamp's opening so it sits over a solid section of the seat post even at 90* will reduce the clamping force at the compression slot. Shims used with carbon posts also need to be inserted so their openings don't align with either the mast's compression slot OR the seat post clamp opening. Keeping these slots and openings out of alignment simply distributes the clamping forces so they don't line up where they can do damage to a carbon seat post.
For an alloy or titanium seat post that doesn't compress under clamping forces the way a composite seat post does, having the seat post clamp opening aligned with the compression slot increases the clamping force on the post (which is what you're looking for, more holding power)... but does no harm to the integrity of alloy or titanium seat posts.
By all means, give flipping the clamp around a try. Just understand why seat post mast compression slots were designed to work the way they do both with brazed on seat post clamps (noting the clamp bolt actually pinches the compression slot closed) and with the more cost-effective, non-integrated seat post clamps found on most non-custom, contemporary frames.
A lovely, fillet-brazed seat clamp with compression slot & key hole by Kirk Frameworks before painting
Last edited by TandemGeek; 10-19-09 at 03:54 PM.