Cyclist's Output Power

by tony kappler   May 31, 2013  

In stage 18 of the Giro, Nibali pedaled vertically for 1000 metres in 45 minutes.
By my calculation, using the formula;
power(watts)=mass(kg) x g(gravitational acceleration=9.8met/sec2) x height(metres), divided by time(seconds), and allowing an extra 20% for windage and rolling resistance, a 70kg rider(+bike) would work at an average rate of 304 watts. Does this sound right? Impressive since my horse weighs about 500kg.

Question for those of you who actually race; if two cyclists are on the road and one is slipstreaming the other, does the front rider get ANY benefit from having the second rider being there. (I'm thinking of some sort of bow wave effect).

My apologies if these subjects have been covered before, I'm relatively new to road.cc

6 user comments

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Horse..... Thinking

Nibali's average output uphill in the Giro was 5.62 W/kg but that's based on guesses, because I don't think he uses a power meter. Infact he's against them (see the quote).

But lets just say that the 5.62 W/kg was right and take it for 70kg, even though Nibali is only around 60kg.

5.62 W/kg x 70kg = 393.4 watts. 90 above your calculations.

Lets also take the "suspicion level" (for doping) W/kg which is around 6.2 W/kg

6.2 W/kg x 70kg = 434 watts....

Not that I know what any of this means, nor do I really care how many light bulbs they can power Devil

Quote:
"Yesterday I did something pretty important. I've done lots of others attacks like that but it was special because it came off.

"Sky has a certain way of interpreting the race. Lets call it scientific, even if it's perhaps not the right term. They work to impose their rules on the race. However, yesterday you couldn't impose a pace; you need legs as certain kinds of strategy don’t work."

Nibali explained that he is in favour of race radios but against power metres. On Monday he suggested banning power metres from races in a message on Twitter.

"People say radios ruin the racing but it’s the riders who decide the best tactic during the race, as I did with other riders yesterday. We aren't radio controlled from the team car," he argued.

"Power metres help you understand how you feel and show your limits but in certain moments we've seen how Sky control their effort. Without power metres that wouldn't be possible."

"At the Tour de France, Team Sky controlled the race with a great team. At the Tour there weren't stages like yesterday or a hard day in the rain. Yesterday was important because I was able to build my success."

http://www.cyclingnews.com/news/nibali-its-a-huge-personal-satisfaction-to-win-tirreno-adriatico

Gkam84's picture

posted by Gkam84 [8780 posts]
31st May 2013 - 2:25

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Why are you adding weight to Nibali, Gkam? That inflates your power by more than 10%.

In fact, I'm really confused. Why is there a 500kg horse riding a bicycle? Would you need to make the horse wear cleated shoes, or could you attach the cleats directly to the hoof? Would a horse's long snout make it more aero? What would a horse wearing lycra look like?

posted by bashthebox [637 posts]
31st May 2013 - 8:46

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Anyway, this should help:
http://www.fillarifoorumi.fi/forum/showthread.php?38129-Ammattilaispy%F6...

The chap who does these is invaluable to follow on twitter if you're interested in cycling power outputs. Though don't treat them as gospel, they're estimations.

posted by bashthebox [637 posts]
31st May 2013 - 8:48

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Gkam's added the weight of the bike as well I think. But the watts per kg figure excludes the bike. So I think the right power output is 337.2 Watts if we use Gkam's figures.

However, your man above ^^ reckons Nibali's output for the first part of the TT was 6.22 w/kg or 373.2 watts. Even for the last 6.4km it only fell to 361 watts. In other words, he rode it f**king hard but measures his effort really well.

I am inclined to agree with Nibbles re power meters but there is no doubt they are useful in some applications - especially for uphill TTs!

arrieredupeleton

posted by arrieredupeleton [547 posts]
31st May 2013 - 10:21

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http://analyticcycling.com/ All the calculations you need for these sort of the questions and more

I am 83kg and generate about 200W. I think that's why I am a bit slower than the Pros Big Grin

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posted by vorsprung [290 posts]
31st May 2013 - 15:20

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Sorry, my horse reference related to the fact that one horsepower equals 746 watts; At 500kg, this is 1.5 W/kg;
pathetic effort.

posted by tony kappler [30 posts]
1st June 2013 - 3:43

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