Originally Posted by
cooker
However, if you look at absolute speed, rather than proportionate, your argument weakens. If you're going 5mph up a steep hill and double your effort (and speed), you only get an extra 5 mph. If you're going downhill at 40 mph and doubling your effort gives you a 25% increase, that's an extra 10 mph.
True, but the amount of time is very different uphill than down, so halving the time on both (which is crazy generous on the DH) you save more total time on the climb.