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How strong is a carbon seatpost?(4 posts)

How strong is a carbon seatpost?Matno
Mar 26, 2003 5:35 PM
I'm wondering about touring loads. I have a pannier rack that only attaches to the seatpost. (Headlands Sport Utility X). Do you think my Easton CT2 carbon post would support it with a load of about 20-25 pounds? The rack supposedly will do 40lbs, but it would cost a lot more to replace the seatpost than the rack so I don't want to take unnecessary chances!

Also, is there much possibility of such a rack having an effect on my CAAD4 frame? It doesn't seem likely since the frame will easily support a rider who weighs a lot more than my 140, but my weight pushes mostly straight down whereas the rack torques a little more.
Very strong in certain directions, not strong in others...PdxMark
Mar 27, 2003 8:36 AM
I suspect your pannier rack will be putting a torquing load against the seat post. That's not a direction the post is meant to be strong in. In addition, the 20-25 pounds will put greater loads at the edges of the clamp (on the seatpost), particlaurly has you hit cracks in the road. I'd get a cheap strong alloy post for touring.

The frame will be way, way fine.
I wouldn'tDougSloan
Mar 27, 2003 8:40 AM
I have no evidentiary basis for this, but I wouldn't try attaching anything like that to a carbon post. I'd get a cheaper aluminum, maybe ti, post and substitute that for touring. If nothing else, it may save the finish of the expensive carbon post.

You can get a cheap aluminum post at Performance for about $9, and they work fine (I have two).

Doug
All right...Matno
Mar 27, 2003 9:22 AM
I guess I'll just "borrow" the aluminum seatpost from my mountain bike. I just realized that they are the same size (my old road bike had a 26.6mm post, so I was thinking it might be a pain to find a cheap spare, but the new C'dale is 27.2). Plus, the seatpost on the MTB is already scratched up... :^)

Thanks for the heads up.