Wigans goes there. Cadence!

[acoggan]

Ugh, clearly a short google would have popped up your comparison between SRM and Quarq

A bit longer Google search would have turned up that I was the first person to publicly report on the accuracy of a PowerTap (way back in 1999, when I was one of their beta testers).

An even longer Google search would have turned up where I evaluated the accuracy of a friend's SRM back in 1996.

More digging still would have turned up where I evaluated the accuracy of a CompuTrainer back in the early 1990s.

Etc...

 

[Franklin]

Ferrari has low standards.

I'm sure he has, but he has no agenda on the cadence of Wiggo, now does he?

The reported cadence as eyeballed by people on this forum (eyeballing while looping a part of the Olympic TT) and Ferrari's post seem to confirm each other. Of course, it's good to know more, but I would be surprised if it wasn't true.

But let me get out of your hair as I'm in no way qualified to discuss the finer points.


And yes Andy, I am chastized, you are an authority on SRM's. I had been reading the standard reviews and a few forums, not going into the nitty gritty

 

[D-Queued]

You have low standards.

And I am liking yours, more and more by the post here!

1. I am one of the testers, silly.

2. The P2M suffers from excessive drift.

3. Quarq PMs also tend to drift more than is ideal, although clearly not as badly as the P2M.

4. I used to say that the PT was the PM that I'd trust the most "straight out of the box", but in the last ~5 y there have been quite a few that were broken but still gave halfway believable numbers, so I'd no longer make that statement.

5. SRMs generally work or don't work, but you can't really trust the factory to calibrate them correctly.

In any case, the point is that you must always wonder about the accuracy of any power data (regardless of the PM used), and can't make the blanket statement that the data they provide is completely interchangeable.

Thanks!

Dave.

 

[Ripper]

Not that I am aware.

OTOH, I do know of at least one world-class female cyclist who was able to maintain her absolute power while carefully dieting to a very low (i.e., well into single digit) percentage of body fat. She lost ~8% of her body mass.

In any case, your question presupposes that Wiggins really went all the way from 82 to 69 kg. As I've said before, I think we actually know more about his absolute power than about his exact mass (same for Froome).

Well, that's the thing isn't it? Riders keep their weight fairly 'close' and can easily BS it. A few kg makes a much bigger difference that a few watts.

 

[BroDeal]

Apparently not.

EDIT: More seriously, can anybody scare up a TT file or two for Wiggins prior to this year? (I know that his 2010 Giro d'Italia performance is out there, but can't find it right now.) That might allow us to at least answer whether his cadence has, in fact, gone done.

Can we get even an inkling of whether it would make a difference?

On another note, why didn't you ever turn "pro." Ferrari raked in like thirty million euros.

 

[acoggan]

Can we get even an inkling of whether it would make a difference?

That would dependent on the magnitude of any change, no? For example, if Wiggins went from pedaling at 110 rpm to pedaling at 95 rpm, then the potential for improvement is greater than if the change were much less (or non-existent).

On another note, why didn't you ever turn "pro." Ferrari raked in like thirty million euros.

I've never really had much interest in being an applied sports scientist, much less a coach/'prepatour" (hope I'm getting that word right!). Besides, it's more fun being the man behind the curtain pulling the strings.

 

[wattage]

Armstrong did 490W at 74kg, Wigans is doing that same now while weighing 69kg.

Enough said.

 

[131313]

Apparently not.

EDIT: More seriously, can anybody scare up a TT file or two for Wiggins prior to this year? (I know that his 2010 Giro d'Italia performance is out there, but can't find it right now.) That might allow us to at least answer whether his cadence has, in fact, gone done.

I posted a link earlier to the video of last year's worlds and this year's OG. He ranged from 95-102 this year, 100-105 last year when pedaling on flat sections of road. In both races, he seemed to pedal slightly faster on slight inclines, though both courses were pretty flat. On average, his cadence appeared to decrease about 2-3 RPM.

 

[acoggan]

Armstrong did 490W at 74kg, Wigans is doing that same now while weighing 69kg.

Enough said.

"Enough said"? There is absolutely zero evidence that Wiggins' power is that high.

 

[acoggan]

I posted a link earlier to the video of last year's worlds and this year's OG. He ranged from 95-102 this year, 100-105 last year when pedaling on flat sections of road. In both races, he seemed to pedal slightly faster on slight inclines, though both courses were pretty flat. On average, his cadence appeared to decrease about 2-3 RPM.

I was looking for complete files (which I know are out there), to be able to compare apples-to-apples.

 

[131313]

I was looking for complete files (which I know are out there), to be able to compare apples-to-apples.

you mean complete files on the same course? Because that's the only true apples-to-apples comparison that would make sense.

On uninterrupted straight flat sections of road, his pedaling rate is approximately 2 RPM lower. Sure, you can probably glean a little more from a power file with an elevation provide and an anamometer hooked up to his bike, but this is enough for me.

 

[acoggan]

you can probably glean a little more from a power file

Well, I know that I can (QA, anyone?).

 

[the big ring]

Well, I know that I can (QA, anyone?).

Just as long as there are no repeated sections in it, right?

 

[acoggan]

(snip)

BTW, I had a thought: have you considered using the critical power analysis I posted to estimate Wiggins' power for his Olympic TT, then back-calculating his CdA? I bet that if you do you'll find that it is quite reasonable (especially when you consider the traffic on the course).

 

[the big ring]

BTW, I had a thought: have you considered using the critical power analysis I posted to estimate Wiggins' power for his Olympic TT, then back-calculating his CdA? I bet that if you do you'll find that it is quite reasonable (especially when you consider the traffic on the course).

Using which value for crr and accounting for wind how?

 

[acoggan]

Using which value for crr and accounting for wind how?

It's only going to be a ballpark estimate in the first place, but to answer your questions:

1) 0.004; and

2) ignoring wind (since you can't account for it, and since 131313 has been - I think - been ignoring it already).

EDIT: Of course, we already know what the answer will be: if Wiggins averaged ~450 W, as you'd expect based on his pre-2012 performances, vs. the ~470 W that 131313 originally estimated, then applying my ROT his CdA must have been 20/5 x 0.005 = 0.02 m^2 less than the 0.23 m^2 that 131313 came up with. A CdA of 0.23 - 0.02 = 0.21 m^2 for someone of Wiggins' height and build is not at all unreasonable, at least for someone "aerodynamically gifted" enough to have won multiple IP titles, set world records, etc. By comparison, at 1.83 m/68 kg I'm very similar to Wiggins from the knees up, and my "on road" CdA under the conditions he raced would likely have been 0.19-0.20.

 

[acoggan]

Just as long as there are no repeated sections in it, right?

??

It doesn't matter if riders cover the same section of road more than once.

 

[the big ring]

??

It doesn't matter if riders cover the same section of road more than once.

My smartassery is too obscure. There's another thread here discussing independent cranks... PT file was supplied... had repeated sections (manipulated file).

A joke is never funny if you have to explain it.

 

[the big ring]

It's only going to be a ballpark estimate in the first place, but to answer your questions:

1) 0.004; and

2) ignoring wind (since you can't account for it, and since 131313 has been - I think - been ignoring it already).

EDIT: Of course, we already know what the answer will be: if Wiggins averaged ~450 W, as you'd expect based on his pre-2012 performances, vs. the ~470 W that 131313 originally estimated, then applying my ROT his CdA must have been 20/5 x 0.005 = 0.02 m^2 less than the 0.23 m^2 that 131313 came up with. A CdA of 0.23 - 0.02 = 0.21 m^2 for someone of Wiggins' height and build is not at all unreasonable, at least for someone "aerodynamically gifted" enough to have won multiple IP titles, set world records, etc. By comparison, at 1.83 m/68 kg I'm very similar to Wiggins from the knees up, and my "on road" CdA under the conditions he raced would likely have been 0.19-0.20.

Are you saying Wiggins' calves are 7cm longer than yours, or describing your body / shoulder width?

I would have thought (dividing the difference between you by two) that having your hips 3.5 cm higher would lead to a definite increase in CdA.

Do you have a pic of yourself in aero?

biketechreview had you down with an estimated CdA of 0.219

Wiggins front (Stage 9) & side (Stage 19) fwiw:

 

[acoggan]

Are you saying Wiggins' calves are 7cm longer than yours, or describing your body / shoulder width?

I would have thought (dividing the difference between you by two) that having your hips 3.5 cm higher would lead to a definite increase in CdA.

Do you have a pic of yourself in aero?

biketechreview had you down with an estimated CdA of 0.219

I'm saying that we are fairly similar in height, mass, and build, w/ the exception of the fact that my lower legs are rather short and Wiggins' seems rather long. I assume that accounts for much of our difference in height.

I'm also saying that, when racing under UCI rules and on courses similar to that used for the Olympic TT, my effective CdA is typically ~0.20 m^2. (Note that that is w/o the benefit of a lead motorcycle.)

For Wiggins' effective CdA to be ~0.21 m^2 under the conditions he raced is not unbelievable (e.g., Millar's effective CdA from one of the Tour TTs a few years ago worked out to an even lower value).

Some English TTers of similar size have calculated effective CdAs for themselves of ~0.18 m^2, due to the benefit they derive from passing traffic on dual carriageway courses.

Smaller track cyclists can have effective CdA values as low as 0.16 m^2.

EDIT: Here are my still wind (i.e., 0 deg of yaw) CdA values when riding a Cervelo P3C:

12.5 cm drop, saddle all the way back: 0.212 m^2
16.5 cm drop, saddle 5 cm behind b.b.: 0.224 m^2
20.5 cm drop, saddle 5 cm behind b.b.: 0.207 m^2
24.5 cm drop, saddle 5 cm behind b.b.: 0.205 m^2

Since I "sail" quite well, my effective CdA in breezy TTs is typically ~0.01 m^2 lower than I get when performing carefully-controlled field tests under dead-calm conditions.

[imgl]http://i38.tinypic.com/13zwl0z.jpg[/img]

 

[the big ring]

Do you know the CdA of that pic? You look like you're sitting upright!

 

[mastersracer]

fwiw, his position in the olympic time trial actually looks a bit more aggressive than his Tour position

http://www.cyclingnews.com/features/photos/gallery-olympic-games-time-trial-bike-setups/234395

 

[the big ring]

fwiw, his position in the olympic time trial actually looks a bit more aggressive than his Tour position

http://www.cyclingnews.com/features/photos/gallery-olympic-games-time-trial-bike-setups/234395

Looks the same to me, other than the helmet.

 

[Cookster15]

Didn't Contador respond the same way in 2009 when questioned about his Verbier performance in the Tour? Wiggins seems to be following the script set before him. But this only adds suspicion.

 

[Ripper]

Looks the same to me, other than the helmet.

I think the different bike makes it look more aggressive, but it is basically the same position. He may have shifted his body this way or that.