Interesting discussion. And seeing how I threw out that 6.2W/kg figure, I've also been interested in tracking the stats.
Unfortunately, we never see the real numbers from the top men, but we can get a lot of data off the SRM website (http://www.srm.de/
). So here are some "facts":
1. Chris Horner:
On the short climb (3km) up to Mende the other, Horner finished 31 seconds behind Contador, having begun the climb with him. Horner's average power output for 10 minutes of climbing was 6.6 W/kg (422W). Nothing wrong with that, it's a really short effort.
For context, consider Horner on Ax-3-Domaines the other day. That climb took him just under 24 minutes, and his power output was 5.8 W/kg (370W). He conceded about 90 seconds to Schleck and Contador and co.
Then even longer was the climb of the Port de Pailheres, which took 48:37, and that was done at 5.4W/kg (344W). Of course, it's not a finishing climb, so the hammer isn't down, but it does reflect what the peloton is doing.
Edit: Also, Horner's data from the Port de Bales are interesting. He finished this day with Basso, conceding approx. 3 minutes to Contador's group by the finish (not 100% sure of the gap at the summit, but imagine it would be 3 min ± 20 seconds). This climb took 49:30, and was done at an average of 342W/kg (5.2W/kg - about the same as the Port de Pailheres of similar duration).
And then very interesting, we also have the data of Chris Anke Sorensen, who has been the last man to peel off for Andy Schleck. And on the Port de Bales, he rode at the front of the peloton for 21:34 and produced 6.1W/kg. The smaller Schleck, riding behind him, would produce less than this - perhaps 5.8W to 6.0W/kg, and that's a good indication of the power produced by those top contenders.
How much are those 90 seconds worth? Using the SRM to 'validate' your calculations, it might be interesting to calculate. Will have a look later, just have to sort out some things first. Cozy Beehive will beat me to it and probably do a better job than I can...
But I think the Tour is substantially slower. The days where climbs lasting 40 minutes or more were done at even just above 6W/kg WITH attacks are no longer with us...and never mind the 6.7W/kg that we've heard of, and know that guys were producing for close to 40 minutes.
On the note of Portoleau, I do feel that all he needs to do is give the times. He has this massive database and if you could show that they did Ax-3-Domaines 90 seconds slower than in previous years, that's compelling. Even with temperature and race situation, you'd have a tough time explaining that difference away entirely. And then the other thing to do is take the average time of the top 20, and positions say 50 to 60, to get an idea of depth. Almost certain it's a lot slower.
The other thing about the power, as Martin points out, is that in theory, if they rode one pace, they'd be faster. But I don't remember one paced riding too often. There are always attacks. Schleck-Contador was extreme the other day, but that's why it would be most interesting to look at the depth and quality.
You can see it in the racing, because as fierce as the attacks are, they're not doing the same damage as previous years, they're less frequent and interspersed with much slower riding, and the guy in the breakaway (Voeckler and Riblon) have held off.