A popular magazine title is always some variation of ‘climb faster now’. While there is a plethora of good climbing advice, which le grimpeur is planning to explore, at the most basic physical level it all comes down to two options.
The two options are: lose weight, or generate more power. And, while it is preferable to do both, the latter is the most important.
While le grimpeur is a bad fan of old-school climbing and technology-free training, there is no doubt that power meters have shed an incredible amount of light on the physical requirements of cycling, and how to improve one’s ability.
For the 2005 Tour de France, Floyd Landis’ coach, Allen Lim, monitored and published Landis’ power data for the race. He did the same for the 2006 Tour and was able to show how Floyd’s performance on the infamous stage 17 was within his physical capabilities when compared to training data, for what that comparison was worth.
In his paper on the 2005 Tour, however, Lim discusses a number of interesting facets of the power component of climbing. For example, in terms of power output measured in watts, to ride the Col de Galibier at the pace of Vinokourov, Botero, or Rasmussen required around 5-5.5 watts per kg of rider and bike, or 350-375 watts for a 70 kg rider. Lighter climbers weighing only 60 kg would, in contrast, only have to produce 300-330 watts.
With aerodynamic drag reduced to an almost negligible percentage (and consequently a limited benefit to drafting), reducing one’s weight while still being able to produce the same amount (or greater) power is a sure way to improve one’s climbing speed.
Power output increases with training. According to Lim, an international pro can produce 321-359 watts for one hour, 364-385 watts for 30 mins, 394-452 watts for 5 mins, and over 800-1000 watts for 30 seconds – with higher numbers for the top riders. Individual riders produce their power differently. Lim explained that Floyd could probably hold over 400 watts for 30 minutes while a sprinter could probably only maintain 350 watts for that period. But while Floyd might only be able to generate 1000 watts at peak power in a sprint, Tom Boonen could hit 1700!
Lim also provides an interesting calculation to derive a rider’s power output on a climb. In climbing, around 90% of effort is required to overcome gravity and the basic calculation is as follows:
(weight of bike and rider (kg) x 9.8 x elevation gain (metres)) / time (seconds) = power (watts)
This gives a rough estimate of power output. For example, I rode l’Alpe d’Huez in 2006 in 62 minutes (3720 seconds) flat, which is around 1120 metres in elevation gain from Bourg d’Oisans to the summit. I was on a Merckx alloy-framed ride, with some spares and two bidons, so perhaps at least 19 lbs or 8.6 kg of bike (I also had a baguette and a round of cheese in the back pockets of my jersey, but will discount those). I was around 69 kg at the time.
So, my power output was (77.6 x 9.8 x 1120) / 3720 = 229 watts
Lim suggests that 10% is added to the total to account for air and rolling resistance, so adding 22.9 would give around 252 watts.
For my weight, I was producing roughly 3.5 watts/kg. According to Lim’s estimations, those are the sorts of figures one would see at the lower end of a Cat 3 racer’s performance, so it looks about right for a rough estimation given other climbing times and that I was really going á bloc that day. Certainly not even close, though, to 5-5.5 watts/kg to give Richard Virenque and Christophe Moreau much competition.
Now, assuming that I was riding Gilberto Simoni’s svelte Scott, tipping the scales at 6.8 kg, with only one bidon (200g?) and no tasty treats in my jersey pockets, what would the result have been? Running through the basic calculation the other way, would give around 60’45″, so a noticeable but not massive improvement, which is perhaps something to consider for those who buy carbon seat posts to save weight. (One would expect lower rolling resistance from light-weight wheels, and we all know that a good set of wheels and well-pumped racing tyres is the way to go; if <10% of the watts were going towards overcoming resistance, though, there is a limit to the extra performance benefit.)
If, however, I could have produced 10% more power, say 250 watts (in the basic equation, discounting the 10% for resistance), my time would have been closer to 56’45″. That’s more like it!
Which also confirms that there are no short cuts to climbing faster. Reducing weight is important, but increasing power output, especially watts/kg, is the crucial factor. Drilling out one’s break levers is no substitute for riding intervals.
The consideration of power versus weight is an interesting one. What it sheds light on, particularly, is the extra power required by a heavier rider to climb at the same speed as a lighter one. In a subsequent column I will explore this in one of the epic climbing battles from the 2005 Tour: Oscar Periero versus George Hincapie.