Thought I saw Big Geo. Hincapie w/ a Camelbak-like blue tube hanging down as he approached the finish line of today's TTT.

Yup noticed that too...another reason I find it odd, everyone doing their own thing. You would think they'd have tested it and found out the best solution. Or maybe that indicates they have tested it and found out aero bottles/bottle placement doesn't make a damn bit of difference?

I couldn't figure out why the P4's of the test team were using standard bottles.



Any ideas?

I thought the aero bottle / fairing was one of the biggest features of the P4. Is it that useless as a waterbottle?

Brad

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3SIXTY5cycling.com

yeah i thought at first maybe it was a sponsorship issue with the Elite bottle brand...but Elite even has their own aero bottle so no idea?

the uci declared the p4 bottle illegal

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

We have a winner!!!!

Explanation? Bit of a hack job.

http://www.cyclingnews.com/...-for-last-minute-fix

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2016:
IMFL #12
http://www.bestbikesplit.com

I just glanced on today's recap show of the TTT, and I could swear one team had a single bottle in an off-the-back holder. Forget which team though

Aero bottles definitely matter -- even just at 0 degrees, a bare optimized bike can be up to 30 grams of drag better than a round bottle on the DT (on the Shiv/Transition). The aero bottle is about the same as a "clean bike" at low yaw.

The UCI has been wishy-washy on this one all year. We had issues at Paris-Nice running our aero bottle against the ST. UCI didn't like that. They've also been 50/50 on Cervelo (from what I've heard). Furthermore, since they've said they won't give warnings, they'll just DQ riders, no teams are taking chances.

That's why we're seeing round bottles. Aero does matter and don't ever forget that....

Mark
MITAerobike
Specialized Bicycle Components
Road Engineer/Aerodynamicist

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Mark Cote
MITAerobike
Specialized Bicycle Components

Mark, when you test bottles have you done it with a pedaling rider? While I know the problems involved with doing so, I do have to wonder--given the bottle's placement between the rider's legs, if the relative difference could change with and w/o a rider?

Just out of curiosity Mark, but what have you found is better at higher yaws, aero bottle or "clean bike" (with a rider)?



That must be frustrating...it's odd that one cannot get a "pre-blessing" from them that can be used to "educate" the commissaires if need be...what was the apparent "issue" with having the bottle up against the seat tube?




I remember Damon Rinard commenting somewhat about rider/mechanic/soigneur resistance to the "non-round" bottles as well (i.e. harder to grip, harder to mount, harder to fill, etc.) as part of the reason the Bontrager bottle wasn't used more by the Discovery crew. Are you saying if not for the UCI issues, the acceptance would be there?

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http://bikeblather.blogspot.com/

Then why, e.g., did Kristen Armstrong race with one in the ITT at the Giro Donne? (That's a rhetorical question, BTW.)

1. It isn't necessary to test with the rider pedaling, but it might be interesting to test with their legs in different positions (if they aren't actually pedaling, that is).

2. My own field tests (while pedaling, of course) with a low-slung cardboard "bottle" on a P3C demonstrated that it had minimal impact upon aerodynamic drag, at least at/near 0 deg of yaw.

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


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

Mark
MITAerobike
Specialized Bicycle Components
Road Engineer/Aerodynamicist

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Mark Cote
MITAerobike
Specialized Bicycle Components

Kudos not only for the data, but also the rapid response (with pictures yet!).

It's a tough one to measure for sure in a tunnel and I think it'd be really hard to measure in a field test. Like anything else, if you can barely measure it in the wind tunnel, it's a subtle drop in drag -- one of those things that could add up but not be the differentiator.

The notes about the guys not liking them for ProTour racing is valid. The small difference in drag might not be worth the chance of dropping the bottles to many people. I can see that and have heard similar reports.

Mark

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Mark Cote
MITAerobike
Specialized Bicycle Components

Just wish I had some good yaw data...we did yaw testing on this when we were prototyping (jeeze, 4 years ago now) but there was some drift in the data at MIT so it's pretty useless. That 0 deg data's from A2 this past winter.

Bottles are one of those tests that I tag onto the bike test budget...:) I can ususally only allocate an hour max to a test like this.

MC

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Mark Cote
MITAerobike
Specialized Bicycle Components

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Mark Cote
MITAerobike
Specialized Bicycle Components

In my experience, the reproducibility of field tests conducted under very low wind conditions is just a good as wind tunnel testing. You do have to wait for good weather, though, and it is a lot more time-consuming (and most importantly, doesn't tell you what is happening at non-zero yaw).

(Directed to no one in particular.)

This fits with the interpretation that the P4's bottle isn't there to reduce aerodynamic drag, but to minimize/eliminate the aero penalty you usually pay for carrying water.

For tests with a rider, yes, I totally agree with you (and have used many of your protocols). I've learned a lot from your papers -- of course from the classic Martin, Coggan, et all paper.

It's front end tests where we're looking at stuff that's small and might or might not be affected by the rider where I greatly prefer the repeatability of testing bike alone in wind tunnel. I'm spending much more time on the track (velodrome and car track) as well as on the road doing power testing these days. The tunnel is still the default as we're busy and don't have a ton of time. But the real world is where we're racing -- why not study there too.

Mark

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Mark Cote
MITAerobike
Specialized Bicycle Components

...and it also fits with my limited field testing of the Bontrager bottle on both my Soloist and P2K ;-)

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http://bikeblather.blogspot.com/

Sounds to me like you guys need to find yourself a good "halfpipe" course near the Specialized headquarters and save the time of packing everything up and going to tracks ;-)

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http://bikeblather.blogspot.com/

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.

Mark

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Mark Cote
MITAerobike
Specialized Bicycle Components