Chase Car Doping

by Rant on July 8, 2015 · 5 comments

in Cycling, Tour de France

Time flies. So it’s been six months since the last post, give or take a few days. After a while, what new is there to say about doping? I suppose I could write about every story that comes along — which would make updating the old book easier — but after a while it just seems like it’s all the same. Different names, different days, pretty much the same story.

Until, that is, one of my English cousins sent me this article. Seems it’s possible to gain an aerodynamic advantage, let’s call it “chase car doping,” from a follow vehicle. And if you think about it a bit, it eventually makes some sense.

After posting on my Facebook page, I got a few responses that pretty much say, “Yeah, we know that. Been done for years. And the UCI generally ignores anything but the most egregious violations.”

What I find interesting is that someone did the research and actually quantified what type of advantage could be gained. As Marcus Woo’s article on BusinessInsider explains:

Using computer simulations, [Bert] Blocken [of Eindhoven University of Technology in the Netherlands] discovered [in 2012] that during a race, the rear cyclist can reduce the aerodynamic drag on the one in front by as much as 2.5 percent. That’s a lot, considering that 90 percent of a cyclist’s total resistance results from drag.

In general, a cyclist feels drag while speeding along. That’s because air gets pushed forward and squeezed into a small region of high pressure, leaving a pocket of low pressure in the wake behind the bicycle. The high-pressure region pushes back on the cyclist while the low-pressure region pulls, creating resistance.

But the simulations showed that a second cyclist close behind would sweep air forward, filling the gap that the first cyclist created. The air pressure behind the first cyclist isn’t as low anymore, so the wake pulls on the first cyclist less, decreasing the aerodynamic drag.

Pretty interesting stuff. Blocken and a graduate student named Yasin Toparlar did some more tests and found:

[I]f a car is within 10 meters (about 33 feet) of the cyclist during a typical time trial that is 50 km (about 31 miles) long, and if they are traveling at a speed of 54 km/h (about 33 mph), then the car would shave 3.9 seconds off the cyclist’s time. If the car were within 5 meters (about 16 feet), the cyclist would save 24.1 seconds.

These numbers only apply for individual time trials, when a car directly follows a lone cyclist. But when the total time difference between winning and losing is often mere seconds, a trailing car could offer riders a big advantage. “With this information,” Blocken said, “you could influence the outcome of the race.”

Now, if everyone is doing this, it’s not much of an advantage. And truth be told, most time trials aren’t in a straight line, so the effect won’t be as strong. Still, it’s food for thought.

Makes you wonder, as the article concludes, just how much aerodynamic assistance does a breakaway or a lone rider get from the motorcycles that zip along with race officials and cameramen. Might be time for some new rules about chase cars, motorcycles and other support vehicles during pro cycling races.

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MattC July 9, 2015 at 3:50 pm

First off, YAY, RANT IS BACK! Welcome kind sir!!

I have to admit I never really knew that the guy in FRONT gains an advantage from a wheel-sucker…I knew the guy behind gets like a 25% decrease (if he is close)…and if there are more than one guy in front it goes up to about 30% or so. I know there is a ‘bow-wave’ off a vehicle (and a cyclist too, albeit MUCH smaller) and if you dared to ride that close to the front bumper of a car/truck you could be pushed along. I had NO idea the distance was that much (10 meters…that’s actually quite a distance!). Hmmmm….”honey, can you please follow me in the car on my ride today? Stay close, just don’t run over me”….Look out Strava!! Reverse drafting??

Rant July 11, 2015 at 11:28 am

Thanks, Matt. Pretty wild, isn’t it? I’m surprised that the support vehicle could be that far back and still have an effect. Definitely going to have someone following me from now own. Might improve my speed on the road. 😉

MattC July 12, 2015 at 9:18 pm

Rant, I’m thinking if only I could get a Greyhound bus to shadow me…I was watching the cars in the TTT today, seems some are a bit closer than others…though I don’t believe I noticed anybody w/in 10 meters…glad you brought it up tho…I’ll certainly be paying attention in the future where the chase-cars are at. Pretty certain that nobody would even notice it as long as the car is behind. I wonder if the riders are that aware of this…instead of risking a penalty for drafting cars for too long on the way back up to the peleton, just pull in front of them and take a tiny rest…and continue to work your way up like that.

Rant July 15, 2015 at 12:03 pm

That would certainly help push a whole lot of air forward, and maybe increase your speed quite a bit. 😉 From what I gather, the riders and teams do seem to be aware of this. The reaction I got on Facebook from a few folks was of the order, “Yeah, we know.”

Meanwhile, I’d be happy for one of those hidden jetpacks that Chris Froome must be using. He really crushed the climb on the first stage in the Pyrenees.

Liggett junkie September 1, 2015 at 10:53 am

I’m sure they’ll make it illegal once they figure out a way to blame Lance Armstrong for it.

Here’s another one —

Tue Sep 1, 2015 11:30am EDT
Reuters
BICYCLE-RELATED INJURIES ON THE RISE IN U.S.
By Kathryn Doyle – Between 1998 and 2013, adult bicycling injuries rose sharply in the U.S., largely among riders over age 45, a new study shows.

“Once we looked at the demographics of who were admitted from the hospital we saw the trend in riders older than 45 getting hurt,” said Dr. Benjamin N. Breyer of the University of California, San Francisco General Hospital, who worked on the study.

More people over 45 ride bikes now than ever before, he said.

“The injury data reflect a change in the demographics of bicycle riders,” Breyer told Reuters Health by email. “If you take a typical 25-year-old and 60-year-old and they have a similar crash, it’s more likely the older person will have more severe injuries.”

* * *

In 1998, only 23 percent of injuries were in cyclists over age 45, which rose to 42 percent by 2013.

* * *

“Cycling for sport really grew in popularity when Lance Armstrong was having his success,” Breyer said. “We’re also seeing a rising in urban cycling and people using the bicycle to commute to work.”

http://www.reuters.com/article/2015/09/01/us-health-injuries-bicycling-usa-idUSKCN0R147K20150901

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