When you are on the the aero-bars your hands are not on the brakes and the your ability to perform accurate steering adjustments is greatly compromised. There

When you are on the the aero-bars your hands are not on the brakes and the your ability to perform accurate steering adjustments is greatly compromised. There is a good answer to this question here: https://bicycles.stackexchange.com/questions/10231/why-dont-tour-de-france-riders-always-ride-their-tt-bikes https://bicycles.stackexchange.com/questions/10231/why-dont-...