How much spare seat post length do you have. If you go from a 175 mm crank arm to a 165 mm crank arm you will probably need to raise your seat by roughly an inch.
You can put me down as somebody who has benefitted from shorter cranks and less leg range of motion following a leg injury and surgical repair.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.