Free Speed on the Bike from Cervélo

Here is a decent piece of research from Cervélo, testing the P4 and a bunch of other tri bikes with various bottle mounts.  For the full bit of research recently published in Lava magazine, click here.  I’ve copied the good stuff below – the part that demonstrates how hanging a normal bottle in a hammock between aero bars (NOT aero drink) actually REDUCES drag.  Quoted article begins from here:

Bottles in Front

Having the most aero solution for bottle storage is no good if you don’t drink. As one athlete put it, “weaving down the road with advanced dehydration is not very aero either.” The big advantage of mounting your hydration to the aerobars is that you always see it. It reminds you to drink, and you drink more because it’s easily accessible.

We compared two options for aerobar mounted drinking systems: a system that hangs down vertically in front of the head tube, and one that mounts a standard round bottle horizontally on the extensions between the arms. What the testing indicated was that the vertical bottle added some drag depending on the system and shape of the head tube, but not as much as a standard bottle mounted on the frame. The really bad part was the straw sticking up.

Figure 2: A vertically-mounted aero drink system between the aerobars increased drag, but less than adding a bottle on the frame.

A standard round bottle mounted horizontally between the rider’s arms, however, was a revelation! It filled in the turbulent area behind the rider’s hands and actually reduced drag. This set-up was not only faster than the vertical bottle, but surprisingly, faster than no bottle at all.

Figure 3: Adding the horizontal bottle between the rider’s arms actually reduced aerodynamic drag by a huge 56 grams on average. That’s a power savings of about 5.6 watts when riding at 40 km/h.

Read more: Free Speed: Cervélo’s Tips on Aerodynamic Hydration : LAVA Magazine
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