I think my rear derailleur is squeaking. It only happens under stronger forces, like 8% grade pedaling. I thought it was my bike shoes/cleats but I lubed that to no effect and it seems like the sound is coming further back. It is much more pronounced on my right stroke which made me think it was the shoe/pedal on the right side.

Anyway the next thing I was going to try was to clean/lube the jockey wheels. Any other suggestions? The chain is new and recently lubed.

Check that your chainring bolts are tight.

Derailleur does not change function based on amount of load - it is on the bottom untensioned run of the chain.

Yep, something else. When the RD wheels need lube, they squeal during a shift.

Do you get the noise when you're out of the saddle?

How loud is the squeak?
I recently chased down a squeak that dissapeared when I got out of the saddle.
It was my shorts on the saddle.
Looking for noises can be a proper rabbit hole.

Doh! I think that rules out the pulley wheels. My next guess is the chain ring bolts as you suggest, they are on the right side obviously so that aligns with the asymmetry as well. I had changed the chain ring at some point and might not have torqued them enough. The sound seemed to be coming further back but it is hard to pin down .. a rabbit hole indeed.

EDIT: chain ring bolts were surprisingly loose.. just tightened them and about to commute home to test..

OK the verdict is in .. chain ring bolts! It was completely silent up all the hills. Thanks Clyde it would have taken me a long time to get to that point at the rate I was going.

Um .. gotta roll that back. I only had 6% max hills going home, the 8-12% are on the way in to work only. It was squeaking again this morning. But, I did notice that it only happens in the biggest ring in back, shift one gear over and total silence. I was not noticing this before as I am always in the biggest ring on 8+% hills.

I think the limit screw may need some adjusting, not sure why it is squeaking from that but I can't see what else could be the cause. The chain looked like it might not have been perfectly centered on the teeth so I tightened the screw a bit to get it centered. If this doesn't do it I will take apart the cassette, and lube and re-install the rings. Other suggestions welcome..

It's probably worth the time to remove and regrease the pulleys, though I can't see how that would affect only the right stroke. My next guess would be a hassle; your bottom bracket may be wearing out.

To paraphrase Click and Clack (the Tappet Brothers), turn up the radio and keep riding. If it's the BB you'll find out soon enough!

Slightly lube the pivot and contact points of your rear skewer. There’s a lot of torque/pressure on those when applying your massive power <grin> and often can result in noises.

You are close .. I took the rear wheel off and as I was turning the end caps with my fingers I got a little squeak which sounded verrrry familiar. I am pretty sure that is the spot. I took off the squeaky cap, cleaned it and lubed around it. I think enough dirt had worked into that area to cause the problem.

EDIT: Yes that was it, did several steep hills with no squeaks. Check that off my list! Thanks for all the suggestions.