Froome told to the world that his victory in the Tour de France will withstand the test of time. To the many people who still have doubts about this, I propose to examine closely a detailed analysis and comparison of the performances of Froome, Contador and Indurain.
The graphics at the left (click for larger picture) shows the climbing time on the horizontal axis and the corresponding climbing power, in Watt per kilogram, of their performances  in relevant final climbs.

Where did these data come from? Froome 2013 and Contador 2013 are my own computations. Contador 2009 and Indurain 1994-95 are historical data by Mr. Vayer and Mr. Portoleau. For the red Froome-data  and the black Contador-data I used the final climbs on AX 3 Domaines, Mont Ventoux, Alpe d’Huez and Annecy-Semnoz. For Froome also the data from La Planche des Belles Filles and La Toussuire in le Tour 2012 were included.  The three blue data points for Contador 2009 correspond to the final climbs on Verbier, La Colombière and Mont Ventoux. Finally the purple data points are the final climbs of Indurain in his Top-Epo tours.
At first sight we see that with the exception of Indurain the data series are very well presented by smooth theoretical curves, from which we may learn some of the hidden secrets.
The Indurain data are “all over the place” . No theoretical model whatever can be fitted to these data. The best way to describe this is to state that Indurain rode at the same high power regardless of the length of the climb. In fat this means that he had an extremely high maximum aerobic power, but he had no, or did not need to use,  any significant anaerobic energy. In plain words; due to his unlimited  use of Epo he had an extreme aerobic power and a corresponding VO2max.
The Froome curve lies entirely and far below all Indurain data, thus anyone claiming that Froome was riding in 2013 at the Indurain level of 1994 should know better.

First some words about the theoretical curves. We can consider a cyclist to be a hybrid machine. He gets energy from aerobic and from anaerobic chemical processes. His aerobic energy reservoir  is virtually unending, but the intensity at which he can use it is limited by his maximal oxygen uptake and his maximal aerobic power. Let us name this maximal aerobic power which can be sustained “endlessly”  as CP – Critical Power. On top of CP he can use some anaerobic power from a limited reservoir. The best possible climb will be when he throws his anaerobic energy into the battle in such a way that he is exhausted exactly on the finish line, not before and no after.

If the foregoing model is realistic then the highest average power on an all-out climb can be computed and/or predicted.

Climbing Power = Critical Power + (Anaerobic Energy)/ Time of the climb

Or in shorthand ;             P = CP + AEC/t

I am personally very surprised and pleased that all the real-world data (except Indurain) could be perfectly well reproduced by this simple formula. Further we now replace our belly feelings by reliable and undeniable numbers as  in the following table.

We see that in the Tour 2013 Froome and Contador had the same critical power (within less than 1%),  and the same oxygen uptake at the CP level. These numbers of CP and VO₂ at CP are so low that we may state beyond any doubt that both riders were clean with regards to Epo-like products and/or practices. However Contador had a much lower AEC than Froome. We all saw that Contador indeed lacked the extra anaerobic explosiveness. Unfortunately almost nothing is known about reasonable numbers for the AEC, nor about possible drugs or practices to boost AEC.
Because AEC is directly related to the capacity to go beyond the aerobic  limit we suppose that this capacity can be raised by intensive and scientifically targettted training. Is this the real secret of Froome and his team?  Maybe Sky and Mr. Brailsford may open the box and give us the complete openness he promised some years ago.

Last but not least we look at Contador in 2009. His blue curve may even supersede most of the Indurain points… and there is a gigantic difference between Contador 2009 and 2013. His CP was in 2009 a full 4% higher, and his AEC was even more than double with respect to 2013.
About Contador in 2009 I have no doubt; doped. About Contador in 2013 ; probably clean but badly prepared.