Spinning a low gear on downhills is often recommended as a good way to develop a smooth stroke at high cadence. However, an alternate approach that can be even more effective is working on your spin while riding gentle climbs.
When you get to a hill, choose a gear several teeth easier than you need or are accustomed to, and spin up at about 115 rpm. Later, work up to over 130 or 140 rpm.
This approach is beneficial because the hill creates some resistance, allowing you to feel the pedals better as they’re going around.
As a bonus, it helps with shifting technique, training you to downshift before the hill.
It’s important not to use a steep hill for this drill. A mild grade of 2-3% works great. A computer with a cadence readout helps you keep track of progress.
Remember to keep your hips steady in the saddle. If they begin to rock or bounce, back off just enough to quiet them again. As you get proficient at a given rpm, gradually increase your cadence.
Why bother with this drill? Smoothness at high cadence makes you smoother during 90-rpm cruising, too. And when you need to rev up to escape a charging dog or contest a city-limit-sign sprint (or the finish of a real race), you’ll have the ability.
I don’t know if anyone else has this issue, but when I try to climb at a high cadence, my legs tie up in knots. My natural cadence on the flats is around 90-95, but when climbing, the steeper the hill, the more I have to let my cadence drop in order to climb comfortably.
I’ve always been intrigued by the difference in pedalling rates. Decades ago when I raced, my optimal pedalling rate in a kilometre TT would be far higher than my optimal pedalling rate in a hill-climb of the same duration.
I’ve always assumed that the cause is the difference in resistance-to-motion. When riding really hard on the flat, a momentary relaxation of effort has little effect. However, when riding really hard up a 15% gradient, a momentary relaxation of effort brings one to a halt. Of course, this is partially due to the fact that one’s going much slower when climbing.