Sorry, no advice here, but I'm watching this thread with fascination because I think we could be twins (knee issues, only use my big chain ring on downhills for that reason, and asthma issues). Most of last season I had an easier cog, with a long-arm mountain bike derailleur on my bike to help with hills, but changed it back because honestly the shifting suffered and I hadn't planned so many hilly rides for this year. I never ever thought about changing out the chain ring too! I'd love the option to make hills a little easier without sounding like the engine that could (literally, on the Horsey Hundred this year as I was going up hills people would look around them to see who was breathing so loudly).