bikex10

Has there ever been a study done on the effects of crank arm length. Yesterday I was replacing the old crank on a bike that I was rebuilding and noticed that it had a 175 on the non drive side and a 170 on the drive. I had purchased this bike used some time ago and have put a fair amount of miles on it. However I was unable to tell the difference in the lengths while riding, infact it did not feel any different than any of my other bikes.
I realize that it must make a difference, but how much and what?
Does the size of the pedaling circle have anything to do with efficency?
Are the shorter lengths for shorter people and the longer lengths for taller people?
How does one determine the proper length and how was the formula arrived at?

well biked

Lots of info here: https://www.sheldonbrown.com/cranks.html#length

aikigreg

After going to shorter cranks, I'm convinced that getting the proper size for your leg length, and even shorter if you have knee problems, is the way to go. I have less stress injuries now for no loss of speed.

MKahrl

Here is the study.

https://www.velonews.com/tech/rev/crank.html