both serotta and mather suggested i use a layback seatpost when speccing frames for me, never even thought to question why
Possible reasons include an unwarranted obsession with keeping the chainstays short, forcing a steep seat tube angle, and allowing for you to move forward in the future. If you start with a straight seat post, you can only really go back from there with various amounts of layback, whereas if you start with a medium layback post you have a fair amount of wiggle room. I don't object to posts which have a bit of lay back per se, I just think the Thomson version is staggeringly ugly.
Possible reasons include an unwarranted obsession with keeping the chainstays short, forcing a steep seat tube angle, and allowing for you to move forward in the future. If you start with a straight seat post, you can only really go back from there with various amounts of layback, whereas if you start with a medium layback post you have a fair amount of wiggle room. I don't object to posts which have a bit of lay back per se, I just think the Thomson version is staggeringly ugly.