carbon bicycle question

Hiyas. I know this is probably an odd venue to seek advice for bicycle inquiries, however I have found this site to be a surprisingly informative place. Anyway I ordered a 2009 Cannondale Synapse Carbon 3 (my first under 30lb bike YAY!) and I was wondeing if I could mount a lightweight rack to the seatpost. Just one of the lghtweight Topeaks with a couple lightweight shirts/shorts/socks etc. 2lbs max weight on the rack, plus 2lbs weight in clothing. I was told I should probably use an aluminium or steel seatpost to prevent the carbon seatpost from cracking, however what I'm more worried about is cracking the frame. This would just be for weekend trips 100 miles or less a day, some bumpy roads mostly to visit friends. This bike should be much more comfortable than my 10yr old Raleigh R300 and about half the weight. I was just wondering if it would be durable enough. II'm 6ft tall 165lbs and the frame is a 61cm seat tube length the largest size it comes in this year the standover height is around 33 inces, actually a little lower than my Raleigh. .

Thanks in advance for any and all help,

Lostboy

I think that what you don't want to do is to use a clamp that puts a lot of pressure on a small area of a carbon tube that isn't reinforced for a clamp. most carbon handle bars will have an aluminum tube where the bar riser clamps down. Seat posts are probably thicker throughout so you can have the height wherever you want and clamp accordingly. Like you stated, I would be worried about clamping to the frame, but that's just an initial thought as I've never had any experience with carbon frames. Maybe there are clamps made to be easy on carbon or something. Doesn't sound like you need anything crazy strong. AnnaLee beat me to the bike club link.

Wowzers, hot girls talking about bikes......I think I found home! Thanks Anna and Wheezy. On a side note I will definitely use an aluminium or steel post to clamp the rack on however my real worrie is the whether the non flexi seatpost will crack the frame.Seat posts are only 10 to 100 dollars the frames probably 1,500 plus to replace.

No amount of load that you could put on a seatpost-mounted rack will exceed the tolerances of a carbon frame. The rack would break at the mounting point before you could do anything to the frame.

But if you really want to get serious, use the Bontrager carbon seatpost rack.

Thanks Adjunct, I actually use Interchange bags on my commuter bike so that will be perfect! And thanks for the tip on the frame thats a huge load off my mind :-)

I'm kidding about the rack. It looks like it'll break if you look at it funny.