Either you're draft legal and it doesn't make much of a difference so you might get a good round road bike for the money. or you're not and you can use an actual tt bike. Most of the drag produced is from your body position, an aero bike with a human is nowhere near a tt bike, it is most similar to a round tube so I wouldn't scrutinize my tube shape too much. especially if I'm drafting most of the time anyway.

I don't think Epic-o was responding specifically to my comments, since I was talking about the expected difference between crank and hub measurements of power due to drivetrain friction, not power losses due to frame stiffness.

In any case, though, it is clear he suffers from some misconceptions. For example, it has been shown a number of times that CdA does not change with cadence. Moreover, the close correlation that exists between Al Morrison's Crr values determined via roller testing (at a constant cadence) and those that I have determined via field testing (always using the same fixed gear set-up to control for drivetrain friction, thus at variable cadence) implies that this effect is also negligible.

Dang! I've always wondered why ocean-going vessels are square...it must be because the physics are completely different when the water isn't perfectly still.

http://www.ncbi.nlm.nih.gov/pubmed/16540850

When you tell someone like RChung, who invented the Chung Method, or Coggan who does stuff like: http://www.wisil.recumbents.com/...20road%20cycling.pdf

that he should be more critical of the science/marketing and then show us a 2d CFD video as evidence of this, it is pretty ridiculous.

That would be like walking into transition and telling Kienle how to train properly.

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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

I had no idea Coggan had worked with Doug Milliken, pretty cool. Ohh back when my all consuming passion was something else.

Dude should swim more!

Drafting doesn't make it no effort and at times you may want to break away/be in a breakaway or chasing the front group, there are many situations in draft-legal racing where you want to be as aero as possible. Aero bikes are also a great thing for non-pro triathletes such as myself who can only afford to have one bike and don't want to compromise their daily riding by only having a TT bike but still want to be more aero when racing. The way you're looking at it is kind of flawed. Don't forget also that most draft-legal races are predominantly flat and aerodynamics are therefore more important than weight.

Or asking Shaun Wallace if he'd ever even ridden a fixed gear.

Damn straight brother. Mark Cavendish has done quite well in draft legal races, and he chooses to ride the Venge with deep section wheels. Now I'm going to go hide before somebody posts a photo of Contador on a Tarmac....

I'm waiting to see if Sagan gets on a Venge.

Nobody else will ever win anything!

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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

Right on.

And for one more notch on the bedpost for aerodynamics, I keep pointing people to this bit of analysis from Flo. It takes the ALPE D'HUEZ bike course to make weight a narrow winner over aero in any triathlon in the world, and even then only by 23 seconds. Even at Savageman the 90/Disc prevails over a pair of wheels over 1.1kg lighter.

Think of all the acceleration!!!! And the climbing!! How is this possible?!!

linky
http://flocycling.blogspot.co.uk/...-aero-vs-weight.html

But if a kg means a lot to you just take a leaf out of one infamous IM CHOO pro athlete and piss out a litre in transition.
[edit: not directed at you jackmott, obviously...! ;-) ]

Tom - For the chart on the left, is that the current model (aero) madone or the older generation?

I'm asking because I'm currently trying to decide between a 7 series madone and the emonda SLR. I'd rather be on an aero bike, but I know the resale of the emonda will be much higher when it is time to sell; and that's kind of a big deal for me. If that chart is indeed the latest madone, then it seems like a no-brainer to go with the emonda.

Cannondale didn't offer an aero bike, correct?

correct

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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

Only if the Venge comes with a "cranial / anal removal" procedure.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

I'm fairly certain that's the previous generation Madone.

I don't recall ever seeing any actual drag comparisons between the newest Madone and the older model...IIRC, Trek just claimed it was ~"25W of free power" requirement comparatively. If that's the case, the newest Madone will be much closer to those lower lines in that chart.

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http://bikeblather.blogspot.com/

Hi Andy. Maybe it wasn't the right reply to quote, sorry for that.

I only know one study that studies the influence of cadence on CdA (http://www.hupi.org/HPeJ/0014/0014.html) and, as you comment, it shows that the influence of cadence is nearly negligible. Nevertheless, this study was performed in the MIT wind tunnel that has some well-known blockage problems for cycling applications so I will take the results with a pinch of salt. If you know more trustable sources that have studied this effect, please share.

On the topic of Crr, you shouldn't have found very good correlation between Al Morrison's smooth roller testing Crr and the one you derive by field testing. Al's data on bumpy rollers (something similar to real world conditions, as the bumps induces similar fluctuations of the normal load to the ones caused by pedalling loads) shows significative difference to the data on smooth ones (http://www.biketechreview.com/...py_Data_BTR_rev1.pdf) so you should get similar differences. The combined effect of minimal wind fluctuations, stiffness of the frame, surface roughness relative to the rollers, etc can make up these differences to make you get similar Crr results.

With this I just want to say that everything should be questioned when facing such a complex study.

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http://cds-0.blogspot.com

sigh

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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

You'll find Trek's claim is with deep section aero wheels and their KVF handlebar, as is our new S5's "faster out of the box" claim.

Comparing the frame alone (all other parts the same), the KVF Madone has about 2 Watts (at 40 km/h) higher drag than our R-series.

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)

No worries. I was just trying to avoid any confusion.


Chet Kyle tested this (in the TAMU wind tunnel?) as well, but I'd have to dig around to find the exact reference.


I said that there was a good correlation, not that the numbers were equal. In fact, on the road I do get higher numbers than Al (but lower numbers on rollers, presumably because my aluminum rollers are smoother than his plastic ones):

http://www.trainingandracingwithapowermeter.com/...st-results-part.html

I would be nice if you could elaborate something instead of sighting




Good graph!. It would be interesting to replicate that study using bikes with different structural properties but the same aerodynamic ones (by employing a fairing for example) and compare the Crr values derived from field testing.

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http://cds-0.blogspot.com

By any chance would have frame difference for an Evo vs the R-series?

Not to mention that Al only applied his "bump" wires to one of the 2 rear rollers he used (but Crr is from a contribution of BOTH rollers) and the plastic rollers obviously will have some compliance in them by nature.

Interestingly enough though...when I did field testing, Al's "1000hz" numbers matched my on-road estimated Crr fairly well up until ~116 psi. That was probably just dumb luck though in choice of the road ;-)

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http://bikeblather.blogspot.com/

10W (at 40 km/h)

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)