Yet another hydration/water-bottle placement thread
Probably everyone wonders just how much time their water bottles helps or hinders them on their bike split. Then they hear about (and possibly read) the Slowtwitch article by John Cobb that shows than an aero bottle on the front of their bike actually SAVES them time. Then they read or listen more carefully and find out that Cobb's study was done with round-tube bikes, so it's not quite as relevant to that $10K Speed Concept or P4 they're riding.
You see claims about dimpled bottles. You see claims from companies like X-lab. You see speedfills. You hear the story about the straw that worsens your drag as much as your $1000 Zipp front wheel helps it. You see pros riding with almost any configuration you could think of to bolster your assumptions.
Yet I can't find any real data out there that are very trustworthy. (People seem to agree that the straw is bad, but disagree about the magnitude of the problem, for example.)
The closest I hear are disclaimers about how everyone is different and you have to test yourself. Well, we all know how practical that is unless you happen to have a low speed wind tunnel in your basement.
So my interest was piqued when I heard on Tri-Talk a few months back that David Warden and crew had actually taken some time out at a Wind Tunnel to do some more testing on various gear, including hydration systems and aero helmets. (If you're unfamiliar with Tri-Talk, it's a podcast by a guy who is involved with the whole Joe Friel thing, but he makes a legitimate effort to back up what he's doing with science...so it's usually worthwhile, or at least entertaining. He also now co-owns a typical store called PowerTri.com)
Last night, PowerTri.com published their article on hydration systems in the wind tunnel.
It's definitely worth a read, but It's also just as frustrating as ever as far as the results being confusing. Warden admits that his methodology is incomplete (e.g., wind only at 0 yaw), and of course it's an n=1 sample.
What he reports is that - relative to a clean bike (a Scott Plasma with him on it) - only the giant PD Aquacell saved any time (about 2 min on IM course).
- The X-lab carbon wing finished all over the place, depending on what was in it (not necessarily in the order you'd expect, either), from +1 minute to +5 min over IM course.
- Torpedo mount was about +1.5 minute
- Most of the other aero drink thing (Speedfill, PD, etc) were in the +2-5 min range
- Gorilla cage on down-tube vs seat tube vs both was quite different (but this clearly is dependent on the bike specifically)
What to take from this? Goodness knows. I wish there were more detail or at least a sense of what was generally applicable vs. specific to his setup...and what about a more realistic yaw?
If anyone knows about a more definitive source on this kind of thing, I'd be interested... but I presume that there really isn't one or we'd all know about it already.
Comments
But let's be fair....in da haus, we recommend high bang for buck and high ROI ways to get faster, whether that I is time and training effort or money. If, tomorrow, we had data that pretty clearly showed a $25-50 investment had the kind of effect of an aero helmet, we'd be all over it.
(And for the record, I'm on their mailing list and just got an email with the link...no long searches!)