My wife and I headed out for a relatively short ride this afternoon. The wind blew briskly from the south, between 10-15 mph. We decided to head for the Veloway, which is partially shielded from the wind by trees.
But it was shielded only some of the time. On one straightaway stretch, we rode directly into the wind. “Wow!” exclaimed my wife. “It’s like someone put the brakes on.”
It was challenging to pedal into the wind. In some spots, I coasted to let Pat catch up to me, and when I came out from behind a sheltering clump of trees, I could feel the resistance. Speed dropped immediately by couple miles an hour.
“This has gotta be good for me,” said Pat, trying to find the bright spot. “I bet I’m burning more calories fighting this wind.”
Well, as it turns out, there is a plethora of material online concerning cycling and wind. One of the cooler tools I ran into is a calculator that can tell you how much power you need to put out to maintain a constant speed if the wind and other variables change. Here’s a look:
Let’s say you want to maintain a speed of 15 mph on a flat course. That pesky wind is blowing at 15 mph also, and you weigh 200 pounds (I wish!). You need to put out 317 watts to maintain your speed, which will burn 4.5 calories per minute.
If only one of those figures changes – let’s say the wind falls to 10 mph, the change is remarkable:
Now these conditions are very artificial. If I added in a grade of any kind, that would have an effect, too. But I just wanted to see what the wind would do to a rider – not hills. We already know hills are tough.
Pat has trouble with hills. But even though the wind today was challenging for her, she accepted it more readily than climbing. By the way, one figure I’ve seen says each 5 mph of wind is equivalent to a 1 percent grade. So a 20 mph wind is like riding up a 4 percent hill.
“Man, I feel good!” she said when we pulled up to the house. She always feels better at the end of a ride, but today she felt like she had really had a workout. And she had.
(Calculator from Science of Cycling: Aerodynamics and Wind Resistance. http://www.exploratorium.edu/cycling/aerodynamics1.html
The Cycling Performance Tips site also has a nice page on “Riding Into a Headwind.” http://www.cptips.com/windrde.htm)