I am using a Deore LX crank with a shimano IG chain.
It performs ok when I'm not pushing hard on the crank. But when I'm in a rough terrain, and when I push it hard, the chain skips. This only happens when i'm on my middle chainring.. And I only noticed it skipping when my right[leg/foot] is in the downward stroke.
In todays ride, it skipped 4-5 times.
skip = when pedalling, it[crank] suddenly looses resistance, about 45-60 deg rev.
I nearly fell to my right side the last time this happend as I hammered.