Originally Posted by
Salamandrine
It actually kind of scares me when I see people stand up for a small hill, and then change gears while standing on the pedals. KLUNK! Yeah, you can get away with it now, but that's got to be hard on your chain.
Chains are cheap. Even a decent 11-speed chain can be had for about $20-$30, and they can last many thousands of miles.
Rear shifts usually aren't all that bad anyway. The bottom half of the drivetrain is where they occur, and that isn't directly tensioned by drive forces. And modern hyperglide cogs allow the chain to flow pretty gracefully to the teeth on the next cog without fully lifting from the previous cog, so the drive tension stays better-isolated to the top part of the drivetrain than it used to.
And of course there's a lot of subconscious technique to it. Just like people unthinkingly reduce pedal force for a brief instant while shifting from the saddle, they subtly do the same out of the saddle.
OTOH, I find when riding with people with brifters that oftentimes they'll lose a few meters shifting for a minor little rise are gradient change. Simply staying in the same gear and stomping for short sections can sometimes be useful too. One example would be cutting across the apex of a switchback.
Brifters provide some extra capabilities, but you can still use them poorly.
I'm somewhat unclear as to how choosing to shift for a small gradient change would cause someone to fall several meters back in and of itself, though. If it was a very badly-executed shift or if their legs didn't respond correctly to the gear change, sure.