Thanks for all the feedback, guys, especially from you people with actual experience with this. I realize switching crank lengths between bikes probably isn't the greatest thing, so if I ever switch, it would probably be a switch across all my bikes (once I commit to a particular crank length). Again, no changes planned at the moment.
Originally Posted by thad
I was thinking about this today actually. So we are talking about a difference of a quarter to a half centimeter right (170 vs. 172.5 vs. 175)? I was just wondering how much of a difference that actually makes, in terms of feel, leverage, etc. Just doesn't seem like much on the surface, but I know tiny adjustments can make a big difference in other areas.
Well, let's assume on the extreme, we're talking about half a centimeter. That's about 3% difference in leverage, max. I suspect it's just better to optimize for comfort and power under normal circumstances. But assuming you're about the same in a range of cranks, I could see a few percent being very important when you run out of gears on unusually steep portions. If you're at a too low a cadence to be effective, this minor difference gets magnified since slightly more power equals slightly faster equals slightly higher cadence equals even more power. Of course, all this is speculation on my part, and not running out of gears would be better...