Evening all, I currently use a small seat-post mounted pannier rack to carry a little bag, with a change of clothes in, for commuting. This is a on an road race bike, with an alu frame (carbon forks and stays). I also have a full carbon frame racer for weekend rides. In June, i'm gonna be doing the Exmouth Exodus, 100 mile Audax. I want to carry that same, lightweight pannier on the carbon frame bike, so I can carry a water-proof, clean jeans and a t shirt, aswell as puncture accessories. I can carry all this with no problem at all on the alu framed bike, but i'm not sure if this is a good idea with the carbon frame. Should I just leave the rack at home and take a rucksack? Or will it be ok? Thanks! EDIT: The bike has an alu seat-post.