handlebar bag or what?

[SouthernBelle]

Any bar bag that meets your needs will do fine.

[KnottedYet]

Ortlieb makes some nice ones (in a couple different sizes) that are waterproof and can also be carried like a shoulder bag. They are rather expensive, but there are similar designs by Seattle Sports and Novarra too.

If you don't need a waterproof bag, there are a gazillion to choose from! Styles from the "classic" Rivendell bags to the sleek and modern Topeak bags. (and they are generally cheaper than the waterproof ones.)

[Thorn]

I'm rather fond of the Topeak line of bags and have a small bag I'll put on my road bike when I want to carry the camera. A large handle bar bag will affect steering, so keep the bag as small as you can. Don't forget, your rain jacket will probably fit in your back pocket.

Can you temporarily put a aluminum seatpost in your bike? My road bike is aluminum so it wasn't an issue to swap the carbon seat post for an aluminum. That way, when I really need to carry stuff I can put on a cantilevered rack and bag. I don't know if that is an option for a carbon frame, though.

[mimitabby]

what color are your handlebars? (where they aren't wrapped) if they're shiny metal, they're not carbon. ..

[rij73]

The bars that come stock on that bike are aluminum. I agree you should get the smallest that fits your needs. Even better would be a good-sized wedge bag that goes under your seat. Anything that wouldn't fit in there you could carry in your jersey. That way, you won't affect the handling of the bike!

[SouthernBelle]

A small saddle bag really shouldn't affect even a carbon seatpost. It's got enough oomph to take our weight through corners and bumps. Same with the bars.

[Geonz]

I like a CamelBak with soem cargo space... but I have a high tolerance for Stuff On My Back.