20 Col du Tourmalet Climb Analysis From 2010 TdF Stage 17

Today's mountain top finish involved the climbing of 18.4 km of the western side of Tourmalet (see detailed 3D terrain here), from Luz-Saint-Sauvier onwards. The Tourmalet is the queen of all climbs in the Tour de France and the roads here are some of the highest in France. The Henri Degranges prime was won on the summit by none other than the lanky, steely looking Luxembourgian Andy Schleck, but he did not manage to gain any time advantage on the Spanish climber Contador as the latter finished an inch away from him. Andy promised a strong effort today to aim one last time for the yellow jersey before the final time trial. It didn't happen as planned.

How It Happened :

1. At 18.4 to go, the leaders were in one group of some 10 riders. The speed, as reported on Eurosport at 19K to go was some 25 kmph. But this was on a mild gradient before the Tourmalet officially began (we can assume their speed dropped by 2 Kmph when the gradient kicked in) . At this point, they had 3:59 seconds advantage over the chasing pack.

2. When the leaders had 18K to go, the chasing group with the favorites had just passed the 20K to go sign.

3.       Time Gap 

 = Time To Finish (Slower) - Time to Finish (Faster Leaders)

Knowing the time advantage of 3:59s (0.066 h), speed of leaders = 23 kmph, and distances left for each as stated above, speed of the chasing pack at 20K to go is then calculated by :

Speed = 20 / [0.066 + (18/23)] = 23.58 kmph ~ 14.7mph

This speed is high as the sections before the foot of the climb were only gradual.

4. When the leaders were at 10.1 K to go, Carlos Barredo from the chasing pack attacks. The time gap to the leaders drop steadily per kilometer.

5. Andy Schleck who is also in the pack chances upon the opportunity to make something happen. With 10K to go he accelerated and passed Barredo. Contador marked Schleck and took his wheel. Both go hand in hand up the climb, eating up into the time advantage of the leaders (by now, their group had also splintered due to several attacks within.

6. The time gap drops rapidly per kilometer after Schleck's attack (see graph below). How rapid is the Contador-Schleck surge? In a matter of 1.6 km, they completely destroyed the advantage of 1:21s enjoyed at the front by Katusha rider Alexandr Kolobnev. He was caught and passed at 8.4K to go in a matter of 28:30s from the start base of the climb.

7. From hereon, Contador and Schleck are the leaders. With 5K to go, they had a 1:15s advantage on the chasers.

8. Alberto tested Andy's legs by giving it a go at 3.8K to go. Andy responded and trivialized the effort but surprisingly, he did not counterattack. Perhaps both may have found that they were at their absolute limits and hence decided to ride to the summit without any further attacks. There was no sprint to the line but the finishing speed as reported on Eurosport was 14.4 kmph, with a margin of 1:30s over the chasing group. Andy gave a hug to Bert on the summit while the latter winked at Andy and patted his face. "You know, we really are the best around here..."

Data & Calculations :

1. Weather : 10 deg C, low visibility with bit of snow in the morning, overcast with a weak wind from the SW, according to Metro News France. Wind can be consequential to the race. Racers like Carlos Sastre know it.  However without a CFD analysis or something similarly sophisticated, the wind vectors are hard to predict given the number of switchbacks, trees, spectators & vehicles. A theoretical analysis of its effect on power to weight ratio was given here for perspectives sake.

2. Procedure : Climb profile divided into 18 sections was borrowed from Velopeloton. Grade was extracted for each individual kilometer. Using a mammoth Eurosport footage recorded using 18 GB of hard drive space (phew), the racers were timed on these 18 sections using my stopwatch with an error of +/- 2 sec. Time gaps/advantages and VAM's were also extracted/timed from the footage video. Power to weight ratio was then calculated with Ferrari's formula using VAM, taking into account the grade of each of the 18 sections. An analysis done this fashion, is a bit on the conservative side opposed to one assuming a constant grade and constant ground velocity. From the perspective of drafting, this analysis is a bit on the overestimating side. All in all, the VAM method is between those two. So for Watts/kg, it is good to represent a figure obtained from this method with an error tolerance of +/- 0.2 W/kg.

3. Change of time gap per kilometer : As shown below : 

4. Climb Time : Time taken by Contador & Schleck to complete climb was approx. 53 mins 25 seconds for 18.4 kms according to race footage. However, from Horner's power output file, it was determined the he took some 52 minutes 22 seconds to climb which puts the leaders at 50:37. This is the figure I will use (with some caution because this depends on how it was operated on). It is quite challenging to put this into perspective with previous editions of the Tour. Data is lacking and I have had to pour into past Cycling News reports to extract any sort of approx. information. I have put together what I could glean in the following table. Please do review it, correct me, or help me fill in the blanks if you can. 

5. Average speed for climb : Av. speed of the duo from calculations (after passing Kolobnev) = 12.62 mph for 8 km. From Eurosport live online, their finishing speed was recorded to be 9 mph. 

6. Average power to weight ratio : Prior to getting caught, Kolobnev and his group exhibited approximately 5.5 W/kg +/- 0.2 W/kg. Average for Contador-Schleck was 6.03 W/kg +/- 0.2 W/kg for 8km after passing Kolobnev. See speed and power to weight ratio below :

7. Climbing Rate (VAM/Ascention Speed) : Average VAM or climbing speed (see detailed explanation for climbing rate) after Schleck and Contador overtook Kolobnev was 1696.5 m/hr. The change of VAM with grade is exhibited below for the parties in the Kolobnev group before the catch and the Schleck-Contador breakaway after the leaders were caught.

Power Meter Data

Both Chris Sorensen and Chris Horner put forth hard efforts during the climb. Surprisingly, Horner made it with the group of chasers and he was the best placed Radioshack rider. As and when I see powermeter information about their efforts, it will be appended here for review/comparisons. The trend of releasing powermeter data is limited in that it monitors only a few riders for a limited amount of time/kilometers before they are expended. But it is should be the most objective indicator of performance, while heart rate is the best indicator of effort. 

UPDATE : Chris Horner's Power Output file from SRM is shown below. His average power output is 5.65 W/kg for the entire climb. Relates very well to my estimate envelope of 5.5 +/- 0.2 W/kg as stated above. Notice that SRM missed out on publishing this cyclist's HR value. It is absolutely important to know his effort intensity level. Viewing such information without HR is as good as no information.

Some Limited Footage

Found on Youtube for your pleasure : 

Part 1 :

Part 2 :

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6 Overemphasizing Power To Weight Ratios

I often get sick of those who're so anal about their dieting regimes and training bruhaha. Seriously, its time these guys had some fun without destroying themselves.

I think my perspectives are best echoed by the following quote :


"The problem with all this emphasis on power to weight ratios is that many riders become obsessive about this and go to extremes. The worst case scenario is that they will go as far as being anorexic or bulimic because of the pressure they, or others put on them to be skinny. Sometimes I have heard riders sounding like female Hollywood stars when talking about their weight! I do feel that there is a serious body/self-image problem in the peloton now that I am no longer a part of it. I say that because if a rider who weighs 69kg with 6.2% body fat thinks of himself as "fat", what does he think of normal people on the street?"

- Bobby Julich, Retired US Pro Cyclist

Additional Resources :

Power To Weight Ratio
Alberto Contador On The Angliru : Climbing Speed And Power To Weight Ratio

29 Power to Weight Ratio

Men
	5 s	1 min	5 min	20 min
World Champion/World Record Holder	23.5	11.5	7.6	6.62
	23.16	11.35	7.46	6.5
	22.82	11.2	7.33	6.38
	22.48	11.05	7.19	6.26
World Class	22.14	10.9	7.06	6.14
	21.8	10.75	6.92	6.02
	21.46	10.6	6.79	5.91
	21.12	10.45	6.65	5.79
UCI Div. I/II Pro	20.78	10.3	6.52	5.67
	20.44	10.15	6.38	5.55
	20.1	10	6.25	5.43
	19.76	9.85	6.11	5.31
UCI Div. III pro	19.42	9.7	5.97	5.19
	19.08	9.55	5.84	5.07
	18.74	9.4	5.7	4.95
	18.4	9.25	5.57	4.84
Cat. 1	18.06	9.1	5.43	4.72
	17.72	8.95	5.3	4.6
	17.38	8.8	5.16	4.48
	17.04	8.65	5.03	4.36
Cat. 2	16.7	8.5	4.89	4.24
	16.36	8.35	4.75	4.12
	16.02	8.2	4.62	4
	15.68	8.05	4.48	3.88
Cat. 3	15.34	7.9	4.35	3.76
	15	7.75	4.21	3.64
	14.66	7.6	4.08	3.53
	14.32	7.45	3.94	3.41
Cat. 4	13.98	7.3	3.81	3.29
	13.64	7.15	3.67	3.17
	13.3	7	3.53	3.05
	12.96	6.85	3.4	2.93
Cat. 5	12.62	6.7	3.26	2.81
	12.28	6.55	3.13	2.69
	11.94	6.4	2.99	2.57
	11.6	6.25	2.86	2.46
Untrained	11.26	6.1	2.72	2.34
	10.92	5.95	2.59	2.22
	10.58	5.8	2.45	2.1
	10.24	5.65	2.32	1.98
	9.9	5.5	2.18	1.86
Note: Values are displayed in watts/kg. The weight should be the weight of the body only. Bicycle, kit, water bottles, etc… are all excluded

This table is from a page in the book Training and Racing with a Power Meter, by Hunter Allen and Andrew Coogan, 2005. This is an absolute monumental work, if you will, in the field of competitive cycling and one of the best texts I have read on the subject of power meter data analyzing. I don't have a PT or an SRM but I adapt the solid principles in the book when training indoors on the Kurt Kinetic Trainer + Power PC system.

The reason I put this up here is for reference purposes and also after watching Fabian sweep the Tour of California prologue yesterday with some serious power.

Efficiency and VO2 max aside, Power to weight ratio (Power in watts divided by body weight in kilos) probably overwhelms all other factors in top level bicycle races. No matter what equipment you ride with, or who your coach is, if your human component cannot produce the numbers shown in the table above, you have no hope competing as you progress towards the top of the game. Better go do something else for a living. Seriously..

Long repeated bouts of training might do it get you there, but now I almost want to believe, even though I don't want to, that the genetic factors overwhelm any training efforts. This also reflects well on a post by AKI a.k.a 'Sprinter Della Casa' on the same topic, where he is somewhat on the same line with me.

Anyway, lets provide an example of top level performance :


CSC's Fabian Cancellara, world TT champ, won yesterday's Tour of California Prologue TT at an average speed of 35mph, with an even astonishing 3 minutes and 51 seconds, thats a 4 second lead over the second man in - Team High Road's Bradley Wiggins, who is also a 2 or 3 time Olympic medal holder back in 2004 in the short pursuit discipline.

Fabian is 80 kilograms and one can very well take his average Power to weight ratio to be 7.6 in the 5 min category (referenced from table above, and I still believe thats a little on the low end).

You do the math, Fabian was nearly producing 608 Watts and above for almost 4 minutes (again, that figure is possibly a little low for Fabian but you get the big picture?).

Thats the power an average novice rider can produce for 10-12 seconds at most, if he's in his best moods.

The book, Bicycling Science by Gordon Wilson, established a somewhat direct relationship between power to weight ratio (in watts per kg) with measured oxygen uptake (in ml/min/kg) in 5 trained cyclists flying the human powered aircraft Daedalus. A higher sustained power to weight ratio naturally elicits a higher breathing capacity.

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