John, thanks for that! This post, from that thread, sums up my problem pretty well:
Originally Posted by cyclistjohn
It's like saying "I've tried size 14 shoes, and I've tried size 15 shoes, and they fit exactly the same." Well, of course they do, if they're both too big!
Originally Posted by 53-11_alltheway
Now that I have 152's on my Mini, I am noticing a real difference. The difference is so striking that I am seriously tempted to chop the cranks on my other bikes. Remember, the cranks on my Strida (170's) are compromised (read: junk) because the factory installed the L pedals in the R side and vice versa. So should I get new cranks, or just shorten them? Or, if I decide to buy a set of those Bulletproof BMX cranks, which size should I get? This leads to the question, HOW short is TOO short? Zinns (article cited in my last post) has experimented with cranks ranging from 150 to 180. And ... ? He writes:
Much to our surprise, every rider we tested performed superbly with the 150s! With one exception, all of us had our highest power outputs at a given heart rate with the 150s in the low power, early part of the test. The exception was that my best test was on 180mm cranks, the length I use all of the time on all of my bikes.
So, I would ask, what about 140's? 130's? 120's? and so on? A good experimental protocol would be to keep trying smaller cranks until one reaches a point at which disadvantages become evident; clearly with 150's that point had not been reached.
Maybe, as Alltheway said, the issue is overrated. But just because all cranks tested perform well enough, it does not necessarily follow that crank arm length doesn't matter. We know that all wheel sizes between 12" and 36" perform well enough, and all frame sizes perform well enough as long as the seat and handlebar can be set at acceptable heights, and so on. But what's optimal? I would like to hear from anyone who's actually tried super-short cranks; and I would especially like to hear about anyone who has found a crank arm length that is clearly too short.