Question: I have trouble shifting when I start a steep climb after a fast descent. I pedal hard as the hill begins, but when I shift to an easier gear, the chain grinds. Sometimes the shift from the big to the small chainring doesn’t even happen. How can I shift smoothly and not lose momentum? — Shelly K.
RBR Replies: Anticipate shifts, and make your gear changes before the chain is under a heavy load. Your description is exactly what happens when the chain is wrapped too tightly around cogs and chainrings.
If you blow it and need to shift when applying lots of force, reduce pedal pressure on the stroke during which the shift takes place.
As soon as the chain makes its move to the larger cog or smaller chainring, resume your power.
That technique is especially helpful for a front shift. As you point out, the chain may be so tight that the derailleur can’t pull it down to the small ring.
Coordinate your left hand with your legs. As you move the gear lever, soft pedal for one stroke. Keep the crank turning but with much less force.
The chain will drop cleanly down. Then resume hard pedaling.