GreenPlease wrote:
Damon, I may have asked this earlier but do you guys have any data on the bike with a bottle on vs off the downtube? In other words, how much, if any, of an aero penalty does running a bottle on the downtube impose? I'd imagine it would be less on a bike like the SystemSix than on the new Super Slice.
Hi GreenPlease,
No hard data, because we only tested the SystemSix with bottles, an intentional choice for this project. Instead of doubling our test runs, we spent that time answering other important questions in the tunnel. :-)
However, as an estimate, based on my past experience including years and years of testing bikes always with and without, adding a bottle on either seat or down tube of "any" bike typically adds between 3 and 5 Watts (at 40 km/h). Based on the SystemSix's down tube dimensions I would guess closer to 3 Watts, which sounds like it's in line with your guess as well.
Cheers,
Damon
Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)