I've been told not to put a tagalong on my carbon bike because the carbon seat post could crack because they aren't designed to withstand the lateral tension of having the tagalong mounted there.
I'm curious if it'd be OK if I were to just mount an aluminium seat post there instead, and then mount the tagalong to the aluminium seatpost. Will that risk the frame getting cracked knowing that the tagalong will create some extra lateral tension, or is the mouth of the seatpost hole generally strong enough to withstand a little extra weight?
This would most likely be a temporary installation, so I'm not concerned about the metal/carbon corrosion issue... only about potentially cracking my seatpost hole.