The following is from Cervelo's website (if anybody should know, you'd think it would be them:
Answer - Soloist for TT/Tri use
I have to start by saying that this is rarely the best option, a dedicated TT/Tri bike will usually give you better performance and more comfort thanks to their dedicated geometry. The steeper seattube, shorter toptube, headtube and chainstays all give you a better TT/Tri position on the bike and better handling when in that position. The Soloist Team is the best road bike available to turn into a TT/Tri bike, but it remains that, the best ROAD bike to turn into a TT/Tri bike.
But that aside, here are the issues. It really depends on how often the TT-road switch is made and how often you use the drops position of your dropbars. If you use the drops regularly and switches often, then clip-ons and STI are the way to go. If you don't switch over and want to go to bar-ends, then the bike becomes more or less a full-time TT/Tri bike anyway and the aerobar options are completely open. Thing to consider:
- The drop from a clip-on aerobar to the drops of a dropbar is very large, so large that for many people the drops are useless and they only use the hood position. This hood position is effectively what you have with a TT/Tri base bar (also called pursuit bar).
- This means that if you want to use the drops at a reasonable height, the top of the dropbar is relatively high and therefore it is important to use aerobars with very little stack, i.e. aerobars and elbow pads that sit as flush as possible with the top of the drop bars.
- It also means that if you don't do that, the drops become useless and you may as well switch to a pursuit bar and save the weight and drag as well as switch to reverse brake levers instead of regular brake levers.
Bottomline: If you use the drops often and want to continue to do so, get aerobars with a low stack height. If you don't care about the drop position, get a base bar and virtually any aerobar (integrated or not) and you'll be fine.