Oh yea, definitely agree with that....I spent more time packing bikes than I did testing them last year...bummer.

Good to hear that your and Andrew's field test results on the aero bottles have matched what we've seen.

Hey thanks for all the info Mark. One more question......what about bottles (aero or round) on the seat tube vs down tube (vs bare bike)?

2) Pro racer water bottle decision criteria: Will I get thirsty? Where can I easily reach it while hammering out my TT? Done. All the rest is bull$hit.

i think EVERYONE did

I'm wondering if its required

not only do you see George's tube hanging in front of his, but you can see Cavendish's valve attached to his chin strap.

I've done both many many many many times on various different bikes. Bottles still matter except on really bad DT bikes. I've tested pretty much every combo of bottle location/size on aero bikes over and over with and without rider.

As with every rider test, it's tough to get good repeatability (usually +/- 15 gF if done back to back) but you can still measure a difference with a rider, with and without bottle. So yes, DT round bottles are measurably worse than a bare aero bike (with a good DT).

Aero bottle results vary per frame. We designed ours to work well with Transition and the key competitor frames (P3C, TTX, DA, etc.) but not to the level of integration that Cervelo has done with the P4 bottle. We effectively wanted a bottle that head on would not hinder the bike but in crosswind could potentially give some lift. That's what we've ended up with -- a good usable bottle that meshes well with all kinds of frames.

Here's some data since we're on ST:
Preface: Shiv bike alone, Roval Rapide wheels w tubular tires (spinning), head-on drag normalized to 30 mph, rho=1.20; my typical protocol
Note, not yaw data here.

Bike, no bottles: 537 gF
(No pic, but same as below without bottle)

Bike, DT 21oz center of tube: 556 gF


Bike, DT Aerobottle, 1 cm gap to ST: 534 gF



Whats the time of savings of this 20gF advantage on a 40km TT?

This just scratches the surface but I can give you guys my MIT undergrad thesis if you're really into this aero bottle thing.

---

...I missed this the first time, but I would like to see that thesis, if you don't mind. I think it would be pretty cool to see (I'm such a geek...I know ;-)

---

http://bikeblather.blogspot.com/

Whats the time of savings of this 20gF advantage on a 40km TT?

The ROT is that ~45gf (or 0.1 lbf) of drag at 30mph is ~= 0.5s/km of time savings. You can do the math from there...

20s over 40k seems inflated, but hey I would do it.

This just scratches the surface but I can give you guys my MIT undergrad thesis if you're really into this aero bottle thing.

---

...I missed this the first time, but I would like to see that thesis, if you don't mind. I think it would be pretty cool to see (I'm such a geek...I know ;-)

Try this link: http://dspace.mit.edu/...84539.pdf?sequence=1

Good stuff...thanks. I only wish there were some drag results in there...

This is like a giant bento box.
Try this link: http://dspace.mit.edu/...84539.pdf?sequence=1