Originally Posted by
Drew Eckhardt
Spending energy on a climb itself will always be faster than trying to carry speed into it.
Speed up a climb is almost linear with power. Pedal 20% harder, go 20% faster. 90% of your energy goes into hauling your carcass up to the summit.
Speed on flat ground is almost proportional to its cube root. Pedal 20% harder, go 6% faster. Even at low speed the overwhelming majority of your effort goes into overcoming aerodynamic drag.
Most of the energy you put in will be lost overcoming aerodynamic drag. Assuming a good position on the drops - 15 MPH on flat ground 74% of your power is wasted on aerodynamic drag, 83% at 20 MPH, 89% at 25 MPH, 92% at 30 MPH.
You might have more fun accelerating before a hill, but won't be faster than using your energy more efficiently.
That last sentence is very context dependent. If you have enough energy to pedal hard on the downhill and the uphill, you will be marginally faster than if you only pedal hard on the uphill. You're only correct if shifts in the the amount of energy between the two are zero sum. On short climbs in short rides where you're not testing limits of endurance, efficiency isn't all that important.