I must admit that I’ve never spent much time thinking about the length of my crank. But, it’s easy not to question when it’s on the longer end of normal, and it just works. My first road bike came with a 175mm, and while I have had the opportunity to try out 172.5mm and 177.5mm, I’ve just stuck with it because I can’t feel a difference. Dylan, as he does, digs into the science behind this question, and while there are some interesting finds in the outliers, it largely appears that the if-it-a’int-broke… approach is the right one.