Earth - Mountain Bike Trails - Episode 212



Pedal Power
Investigate how your legs and your bike work together. You'll need a gear bike equipped with a speedometer and a flat stretch of road or playground. Mark off a distance of about 50 meters (you can estimate it by walking 50 long paces). Shift your bike into a low gear, one where it feels easy to pedal. Start at one end of the 50 meters, pedal up to a maximum speed of 8 miles per hour (about 13 km/h). Count the number of times your pedals went around during the 50 meters. Shift into a middle gear, and start again, counting the turns of your pedals once more. Finally, shift to a high gear and repeat the procedure one last time. What do you notice? When is it better to be in a low gear, compared to a high gear? What if you tried the tests at 12 mph (19 km/h)? What if you were pedaling up hill?