Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In



Which is harder? Comparing power meter data from the Tour de France and the Tour of California

Coach Dirk Friel compares rider power files from the Tour of California and the Tour de France and comes to some surprising conclusions.

Don't miss a moment from Paris-Roubaix and Unbound Gravel, to the Giro d’Italia, Tour de France, Vuelta a España, and everything in between when you join Outside+.

Hincapie leads
The stage 6 break in California

By Dirk Friel

In the world of cycling the biggest race of them all is the Tour de France. The prestige, popularity and history of the race make it the ultimate cycling event for cycling fans and professional racers alike. The race has stood the test of time and is quite possibly the hardest sporting event in the world considering it lasts three weeks, forces the riders to race for up to seven hours a day, and covers some of the highest roads in Europe.

The Amgen Tour of California can’t compare in terms of legendary status, and with only eight days of racing the California tour is roughly only one-third the length of the Tour de France. However, the 2010 edition had many riders and team staff members saying it was too hard. In fact if you look at the results for just the stage 6 between Palmdale and Big Bear Lake (7,000 feet above sea level) 11 riders didn’t make it to the finish line within the 9 percent cutoff time, and 17 starters simply decided to drop out. That makes 28 riders who never made it to the start of the stage 7 time trial in Los Angeles. Less than half (63) of the 128 starters actually officially finished the entire Tour of California.

Perspective from a grand tour veteran

Team Saxo Bank’s rider development manager, Bobby Julich, had plenty to say about the most recent edition of the Tour of California when asked how hard the Big Bear stage was. “The Big Bear stage was one of the hardest stages I have seen anywhere. It was solid climbing right from the start and then never let up. I think that the hardest part of the stage was that it was almost all at altitude and was over 220km long. That was truly a grand tour-like stage, and perhaps even harder than most. I was a bit surprised to see a big group finish together at the end, but it just goes to show that many riders were on form and motivated for the Tour of California this year.”

OK so the Big Bear day was hard, but how hard was the Tour of California to finish? Was America’s most prestigious event simply too hard, and if it continues to be as demanding will it be to the detriment of the event moving forward?

Julich provided his unique insight to this debate. “When you look at the way the race came down to the time trial, you would imagine that it was exactly the same type of race as years past, but I can tell you that the guys were already exhausted after the third stage into Santa Cruz. The organizers elected to put some sort of climb into almost every stage, so there was never time to relax and recover in the race. With the date change, many U.S.-based teams were motivated and they wound up canceling each other out on many of the difficult stages. Everyone did their homework and prepared well, but I was surprised to see such small time gaps at the end.

Sorensen left nothing in the tank
Sorensen skipped California to go to the 2010 Giro, where he won stage 8.

“I hope that this doesn’t make the organizers try to find an even harder route for next year or else it could scare away some of the European guys that were using this race to get started again after the classic season. Perhaps the organizers should think about making the final of the stages a bit more selective instead of having the real ‘teeth’ of the race often far from the finish.”

Comparing the Tour of California to the Tour de France

It is hard to argue with an experienced rider such as Julich who himself has finished on the podium in the Tour de France. In an attempt to add some objective data to Julich’s opinion we might find some answers by simply comparing and contrasting the eight hardest consecutive stages of the 2009 Tour de France with power files collected from this year’s Amgen Tour of California.

For Tour de France race data we chose to use power files collected during stages 2-9 of the 2009 Tour from Team Saxo Bank’s Chris Anker Sorensen. Sorensen’s race files can be seen on the Training Peaks Web site.

For 2010 Tour of California data we looked at power files from Darren Lill of Fly V Australia and Jakob Fuglsang of Team Saxo Bank.

To help determine how hard the Tour of California was we narrowed down the race data to look at five different categories:

Lill's Tour of California power
Lill's Tour of California power
  • 1. The hardest stage as measured by Kilojoules
  • 2. The total Kilojoules for the eight consecutive days
  • 3. Duration (hours) of accumulated winning stage times
  • 4. Hardest stage measured by Training Stress Score (TSS) value
  • 5. Total accumulated (eight-day) TSS 9oints

Kilojoules- The hardest stage
Lill- 4844kj, stage 6, ATOC: Big Bear
Fuglsang- 6364kj, stage 6. ATOC: Big Bear
Sorensen- 5652kj, stage 7, TdF: Barcelona to Andorre Arcalis

This is a toss up. Fuglsang’s kilojoules were so high on stage 6 because he was in the breakaway for nearly all of the stage (see photo above). Even though there is no clear winner within this category, the Big Bear stage in California absolutely measures up to the hardest stage of any Grand Tour.

Darren Lill
Lill leads the chase on stage 5 in California

Total accumulated KJ’s
Lill- 28,221kj (avg 3,527kj/day)
Fuglsang* – 29,061kj (avg of 3,632kj/day)
Sorensen- 31,479kj (3,934kj/day)

And the winner is the Tour de France at an eight-day total accumulated value of 31,479kj and an average of nearly 4,000kj a day. The Tour of California is just behind with a daily average of just over 3,500kj a day.

*Fuglsang’s stage 8 is not available, but we can assume it was around 3,000kj based on Lill’s power file. The two finished in the same group together, tied for 40th place.

Winner’s accumulated stage times
The 2010 Amgen Tour of California’s winner, Michael Rogers, completed the race in 33 hours  and 8 minutes, as compared to 33 hours and 3 minutes for the accumulated finish times for stages 2-9 for the 2009 Tour de France winner Alberto Contador.

There is no clear winner within this category. The times are almost exactly the same.

Hardest stage measured by Training Stress Score (TSS) value
Lill- 361TSS, stage 6, ATOC: Big Bear Lake
Fuglsang- 431TSS, stage 6. ATOC: Big Bear Lake
Sorensen- 391TSS, stage 7, TdF: Barcelona – Andorre Arcalis

TSS is a very valuable metric to track since it takes into account the intensity of the race as compared to the individual’s functional threshold power value. Besides an intensity factor being accounted for, the TSS value also takes into account the duration of the race. This has much more meaning than kilojoules since kilojoules do not account for the relative intensity of a race. What might be a threshold pace for one rider may be a lower tempo type zone for another, yet if the two riders weigh the same, and recorded exactly the same watts, the KJ’s would also be the same.

Yet again another toss-up here. Fuglsang recorded an enormous 431TSS points, since he was in the long breakaway group. In contrast Sorensen measured 391TSS points within stage 7 of the ’09 Tour de France. Fuglsang would have had a lower value if he hadn’t been off the front for so long. It seems as if the hardest days in the grand tours measure around 400TSS points.

Total accumulated (eight-day) TSS points

Sorensen's data from the Tour
Sorensen's data from the Tour

Lill- 2254 TSS
Fuglsang- 2192 TSS
Chris Anker Sorensen- 2152 TSS

The Tour of California had a slight advantage when you compare the total accumulated TSS values of the two riders in the Tour of California versus Sorensen’s highest eight-day accumulated value from the Tour de France.


Now of course it goes without saying that the Tour de France as a whole is harder since it is three weeks long, but now we can see how the Tour of California is just as difficult as the hardest week of the Tour de France. The U.S. domestic teams certainly deserve a lot of credit for any amount of success they find at the Amgen Tour of California. The race has evolved to a level where the European-based riders can’t simply show up with sub-par fitness. Just finishing the Tour of California now pushes each rider to the limit and keeps pretenders away.

Whether this is good or not for the future of the Amgen Tour of California is yet to be seen. One thing that is certain is if the race continues to be as hard as this year’s edition some of the bigger names in the sport may opt to skip the Tour of California as their classics season ends.

Dirk Friel is the chief marketing officer for