This past spring I injured my knee. It sucks. PCL tear lvl 2 and some issues with my patella tendon. I completed about 6 weeks of physical therapy and now feel much better.

Prior to my injury I was able to climb 18% grades in 22t/34t gearing with a 175mm crank and 622-40 wheel. I weigh about 220 lbs (tall male), bike is 35 lbs, and load was approx 25-45 lbs depending on how much water/food I'm hauling. I never really had issues. This was in the Rocky mtns summer 2013.

This year I toured upstate NY via the Erie canal and then linked up to the Adirondack Park loop. I had to bail out on the mountains pretty dang early because my damn knee couldn't handle the exact same configuration as before. My knee gets better daily but before my next mountain tour I am going to need some help. Or, at the very least, an EXCELLENT bail out option. I can and have balanced my bike climbing up these mega grades at 2 MPH or so. I would love to spin @ 80 RPM at these speeds.

So, who else is running some superbly low gearing? 20t/42t? Longer cranks (I am 6'4" with a 33.5" inseam)? Smaller wheels? I've got a White Industries MI6 rear hub so I'm not TOO concerned about torquing it to death. This hub comes standard spec'd on many tandems.

Oh, and walking hurts about 1000x more than cycling up big hills. So don't even mention the option 'walk up the hill.' It really aggravates my knee to walk up steep grades, pushing a loaded bike, for more than a few steps. I would rather go at a crawl on my bike.