Originally Posted by
Miele Man
Okay, so some carbon fiber seatposts can take a seatpost mounted rack. I guess it's okay as long as the rack is mounted as low on the seatpost as possible in order to minimize the cantilever effect. I'd still be hesitant to do that unless I knew for sure that the seatpost had the extra strength needed.
I've seen allow and steel seatposts bent due to excessive weight on them.
YMMV and sounds like it does.
Cheers
I know Alpha Q, ENVY, Ritchey and Zipp posts work from personal use. I would expect any seatpost from a major manufacturer to work as well.
The twisting force an adult stoker is putting on the seatpost through the stokers handlebars in a full out out of the saddle sprint has to be an order of magnitude higher than a 20 pound rack.
I think the hesitation to clamp a rack to a CF seat post comes from the admonition not to clamp anything to CF handlebars. However, there’s a difference between how Handlebars and Seat Posts are made.
Handle bars are only made to clamp in the one place where they are attached to the stem. whereas seat posts are designed to be clamped anywhere along their length above the minimum insertion length.