I've read through all the chain skip threads that have gone before, and I still can't figure out what's causing mine--or more importantly, how to stop it from happening.

I had been experiencing some chain-skipping over the rear cogs when I would crank down hard in either of the two smaller cogs, most notably in wet weather. Cleaning & lubing didn't help much, and the problem worsened over time.

Eventually did a full overhaul, as stuff was getting worn out anyway. Other problems made themselves apparent and I ended up with new bb, chainrings & rear der. as well as the chain & cassette.

So, now I'm riding on new chainrings, new chain, new cassette, new rear derailleur--and the first rainy day I ride in, the chain skips a tooth when I'm pushing hard in top gear (big in front small in back). Once again, cleaning & lubing doesn't solve the problem.

What's left to fix? I guess an easy solution would be to stop pushing big gears, but in general I find it's easier to adjust a machine than it is to adjust my habits...

Any guesses what might be causing this chain slip now that all of the usual suspects have been eliminated?