…or as the poorest running GCN video joke goes, ‘size matters’.
I’m probably too soon with this pronouncement, but after 4 rides with my new 165mm crank arms, I can say with some confidence say that I made the right choice.
As I wrote yesterday, I’m feeling like I’m where I should be in my pedaling space, but I should also add that the stroke seems to be a little more efficient, with fewer (or even no) ‘dead spots’ that I never knew were there till they disappeared. It makes me wonder if I should have gone down to 160mm, but a half a centimeter is a good start.
By the way, once you reduce your crankarm length you need to raise your saddle up because the bottom of your leg extension is now higher. However, because you are reducing the ‘radius’ of the pedal stroke and not just the vertical distance between saddle and pedal, you should probably not raise it a corresponding 5mm…maybe 3mm or 4mm.
There always seems to be something to learn in this business.
The Vicious Cycle 
Is it reasonable to say that a shorter crankarm could be better for older riders (like me; 66)? I realize generalizations are fraught, but I really am ignorant about the virtues and pitfalls of various lengths. Pretty sure mine are 170…
I guess if shorter cranks help with knees then they would help with older riders. This 57 year old is appreciating it at least!
It has never occurred to me to measure my crankarm. I live in a world of blissful ignorance.
Ignorance is cheaper, that’s for sure.
I just bought a 50/34 crank w shorter arms: 170mm vs the usual 172.5mm. Then watched the GCN video this morning and now read your post, Gerry, so now I wish I had gone for 167.5 or even 165mm. (Didn’t dare to decrease too much 🙂
Yeah, I was a little concerned, too, but in the end I don’t feel the difference much, other than what I wrote above. I’m now thinking 160s might have been possible!