Yes. It helped her. Our bike came with the same crank lengths that you have. I like the formula 5.5* inseam = crank length in mm., inseam meaning the standing in your socks, a book in your crotch method, not pants inseam. For my stoker that worked out to 149mm. I bought a shortened stoker crankset from these folks: Short Bicycle Cranks
They provided the 172.5 version shortened down to 151mm Your ideal crank length spec might be different.
The shorter cranks have worked out well for us. I think we're a little slower on the climbs because cadence is lower and so her leverage used to be greater, but maybe a little faster on the flats and shallow or short climbs because we can use higher cadence effectively. She much prefers it anyway and that's the end game.
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