 A seat that is not held in place properly can be dangerous if not at least uncomfortable and annoying.Newer and better designs of the piston style seat post have minimized all forms of wiggle and seatposts with actual adjustable pistons built into the post are even available.Parallelogram suspension seat posts use dual linked bars that connect the saddle clamp to the post, and all operate in an arcing motion although some arc backwards and others arc forwards.