Pulling ahead on downhills: pedal before resting

A downhill after a climb is a great place to recover. But if you're racing to the bottom, it's better to pedal past the top before easing up. The video after the jump demonstrates this in a very controlled setting, with two carts rolling down a pair of smooth ramps - analogous to cyclists coasting down a smooth hill.


One of the carts has a spring-plunger that can be used to provide a push at the top of the ramp, just as if a cyclist pedaled at the start of a downhill before coasting the rest of the way.

Coasting vs Pedaling from Ed Price on Vimeo.

It's worth noting that this effort doesn't just open a constant gap, but that the gap continues to grow - the initial effort continues to pay off all the way down. Specifically, the distance gap grows steadily with the time you've been descending (at 10 seconds, the gap is twice what it was at 5 seconds) and in proportion to the difference in your starting speeds at the top of the hill (if you double the difference in starting speeds, you'll double the distance you're ahead at a given point in the descent). Because you are speeding up as you descend, the time gap does not grow as quickly as the distance gap. As a rough estimate, a 10mph difference as you start down a 5% grade will gain you at least 6 sec after the first 25 yards, and at least 1 more sec after the next 25 yards. At the end of this 50 yards, you'll be going about 18mph while your coasting friend would be going about 14mph.

Caveats:

• Of course, if the downhill is steep, twisty, or technical enough that you have to use your brakes, you may get less payoff. But if you reach those sections first, then hit your brakes, you still get an advantage. 
• Once you and your competitors' reach similar top speeds (think sandy surfaces or wind resistance) the gap will stay constant from then on.
• The ultimate caveat is that you typically spend way more climbing than descending, so it's easy to make up a little time if you're a strong climber.