In the thread of discussing winter weight gain (http://community.active.com/blogs/GaleBernhardt/2011/09/13/right-now-i-m-motivated-to-eat-well-what-happens-in-winter) , Facebook reader Steve Douglas sent me a link to The Science of Cycling website (http://www.exploratorium.edu/cycling/aerodynamics1.html) .
To see what your winter weight does to your speed, enter that number in the box for “your weight”. Put velocity at 10 mph, zero wind velocity and a grade of 10 degrees. Hit “calculate” to see the power required to maintain constant velocity. You’ll get a wattage number. Write that number down.
Now enter your summer racing weight keeping everything else the same. You’ll see that less watts are required to power your bike – which makes sense.
Since many of you do not own power meters, you can get a better idea of cost in speed. Begin making the velocity number faster by tenths of miles per hour, then hit “calculate”. Keep making the speed faster, until you equal the power number you wrote down for your winter weight.
Assuming I didn’t lose any power, in pure watts, by keeping my weight down 10 pounds I picked up nearly 1 mph (0.8 mph). Picking up 1 mph on my early races would make a big difference – especially if I could improve the power number rather than worrying about peeling off the pounds.
A few weeks ago I had a rather blunt reminder of how much work 10 pounds makes on a climb. This day was the primary incident that spurred my interest in keeping winter weight gain minimized. To go watch the USA Pro Cycling Challenge I packed a backpack with 100 ounces of water and carried 48 ounces of water on the bike frame. The weight of 148 ounces of water is just shy of 10 pounds.
I had food and extra clothes in the backpack as well. The pack and all the water was probably some 12 to 13 pounds. Since I always carry some 48 ounces of fluid when I ride, I figure the backpack was a physical example of riding with around 10 pounds of extra weight.
In one word – ugh.
Want a harsh visual and physical reminder of how expensive (in miles per hour) that winter weight gain will be? Go ride your favorite course with a 10-pound backpack and watch your average speed plummet. Notice how hard it is to pedal the bike. Between the bike calculator and the loaded backpack, perhaps you’ll find incentive to keep winter weight gain minimized?