strock 

My wife and I recently acquired a used Terratrike Rover Tandem. The trike is equipped with an Independent Pedaling System (IPS). The captain's crank has 170mm arms, and the stoker's crank has 145mm arms. The 145s work well for my wife, but the 170s are long for me, and I'm finding them a bit hard on the knees. (I run 130s on most of my recumbents to keep knee flexion relatively low.) So, I want to go shorter. I see two options. One would be to use crank shorteners. The other would be to replace the current captain's crankset with a non-IPS crankset. The advantage of the second option is that it would enable me to run a smaller chainring, effectively lowering the gearing on the bike, which is too high for some of the hills around here. The disadvantage is that the captain, as I understand it, would lose the ability to coast while the stoker was pedaling, although the stoker would retain the ability to coast while the captain was pedaling. Is that right? If I do go with shorter cranks and a smaller chainring, I'm assuming that my cadence would increase. This would require the stoker to increase her cadence, too, quite possibly beyond her comfort level. Is there a way to compensate for that, possibly by changing out the timing ring on the stoker's crank? If so, would I need to go larger or smaller? (I'm guessing larger.) Thanks in advance for any and all advice.