Putting aerobars on a rode bike does not a time trial bike make.... It can also cause your bike to lose stability (unless your bike was designed specifically for this....there are only a few road bikes on the market that have been made for this dual purpose....the cervelo soloist is one such bike and is one that I have in my stable of bikes) which will negate any aerodynamic avantage. The lack of stability can actually make you slower and add distance to your time trial from the side to side motion created by the instability. If you are still going to put aerobars on your bike, you really will need to think about purchasing a more foward seatpost.

Check out this article on the Soloist and note some of the comments of about putting aerobars on a regular road bike.

http://www.bikesportmichigan.com/reviews/soloist.shtml