Originally Posted by
jeffpoulin
I used a Topeak beam rack with a carbon seatpost for about 3 years. It worked well for me. Never swayed and I didn't break the seatpost. I only replaced it because the Topeak bag eventually died (broken zippers and a hole on one side). So, a beam rack and CF seatpost can be done.
I actually use this as we speak to carry lunch, clothes, any small items. The one I use is the Carbon beam rack with a carbon post and a topeak trunkbag. but have the beam rack maybe 1/2 inch away from the post clamp. I also replaced the bolts with titanium to lighten the load. Works flawless and I am the envy of my commuting area with that rack on my system six. Rack never moves and is crazy light but strong. I once had a quick release rack but they move all over the place and are too bulky for a road bike.