Originally Posted by
cxwrench
You're confused about suspension and efficiency. It's like high vs lower tire pressure, or even 29ers being more efficient than 26" wheels. Allowing suspension to absorb the bumps/rocks/whatever of rough terrain is always more efficient than a rigid fork bouncing off that stuff. You're not 'losing' any energy by not locking a fork out offroad. I think we're running into some Dunning/Kruger in this thread.
If I'm pedalling while standing, I'm probably climbing. If I'm climbing I'm going at a slow enough speed that the tire is not going to bounce off anything.
If I'm not climbing, I don't lock the fork.