- Jul 5, 2009

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I've done a bit of analysis that I thought I'd share. Recently I became curious, wondering why the Tour de France speeds slowly crept up through the 80's and have levelled off in recent times. The glib answer is doping, but if so then how did the Tour change as a result?

I began by taking to representative years; 1980 (pre oxygen vector doping) and 2000 (middle of oxygen vector doping period).

I went to "memoire du cyclisme" and looked up each stage's distance, amount of climbing, and winner's time. Firstly, I discarded prologues and all other time trials.

I then went to work calculating the speeds for all stages with multiple categorized climbs (HC, 1, and 2). The total amount of climbing and stage distance were considered as confounding variables. The shocking result is that between 1980 and 2000 the average speed on a climbing stage went from ~31.5 km/hr to ~33 km/hr with variations as expected due to length and amount of climbing.

I found that a bit shocking! What this indicated is that the change in eras resulted in less than 5% difference! Within statistical variation, this would be unlikely to completely disrupt the sport. And certainly doesn't account for the overall average change in TdF speed.

That was when I went to work analyzing the flat stages. Each Tour (1980 and 2000) had 10 stages characterized as flat. The average length of flat stage was 206.6 km and the average speed was 36.8 km/hr. The speed was a fairly good linear fit to stage distance as you'd expect.

In 2000, the average length of flat stage was 204.5 km (i.e., virtually identical), but the average speed rose to 42.9 km/hr! That's a 6.1 km/hr (16.5%) difference in speed. Remarkable. When equated to average power output, assume that wind resistance dominates and that it rises by speed^3. This means that the average Tour rider in 2000 was putting out nearly 50% more power during a flat stage than a similar rider in 1980!

I believe that this is the true effect caused by oxygen vector doping, and why the average rider would need to dope in order to survive.

Regards,

John Swanson