Seatpost clamp question

[scottcw2]

All 3 of my posts have about 2.5-3cm of clamp length. I am looking at a new post with less clamp length.

What is the minimum clamp length that is safe before you would be concerned about the rails not being sufficiently supported? Thanks.

[Tobias]

For me it would depend on my weight and saddle rail type. Assuming the post itself is designed as needed to handle the stresses, using shorter post clamp will not make a huge difference on maximum rail bending, but will create a much higher point load which could damage the rails by crushing or shear stresses.

I'm curious just how short a clamp the new post has? Most I've ever seen seem about the same.