My current inseam measurement is 36" (it gets shorter as you grow old). For most of the 59+ years I've been riding, conventional thinking was that I should get long crank arms to take advantage of my long legs. The thinking being that longer crank arms give you better leverage, and they do. On the four bikes I currently ride, the shortest cranks I have are 177.5 mm and the other three are 180 mm. I've used cranks as long as 195 mm (Zinn).
Current thinking is that shorter cranks are more efficient and you can even produce more power with shorter cranks. The reason being, it's better to spin faster in a lower gear with shorter cranks than it is to push a big gear with long cranks.. My own personal experience has been that longer cranks make me faster in some situations, but are more tiring on long rides. So, I might want long crank arms to ride up Flagstaff, but shorter ones to ride a century.
So, should you go with shorter cranks or not? Here's my thinking, if you have a mountain bike or a touring bike set up with triple crank,, I'd probably go with shorter crank arms. But most road bike set-ups have limited gear range and a limit on the largest cog you can use. You might not be able to find a gear low enough to spin with that short crank. If you are constantly wishing you had a lower gear, don't go to shorter cranks. You might even want to consider longer cranks. If you are mostly doing long rides over rolling hills, shorter cranks might be the way to go.
Current thinking is that shorter cranks are more efficient and you can even produce more power with shorter cranks. The reason being, it's better to spin faster in a lower gear with shorter cranks than it is to push a big gear with long cranks.. My own personal experience has been that longer cranks make me faster in some situations, but are more tiring on long rides. So, I might want long crank arms to ride up Flagstaff, but shorter ones to ride a century.
So, should you go with shorter cranks or not? Here's my thinking, if you have a mountain bike or a touring bike set up with triple crank,, I'd probably go with shorter crank arms. But most road bike set-ups have limited gear range and a limit on the largest cog you can use. You might not be able to find a gear low enough to spin with that short crank. If you are constantly wishing you had a lower gear, don't go to shorter cranks. You might even want to consider longer cranks. If you are mostly doing long rides over rolling hills, shorter cranks might be the way to go.