Originally Posted by
Xsive
Chaadster, your words exude confidence; thank you!Toe overlap is only a concern while doing track stands at red lights.Any thoughts about crank arm length and how a 170mm crank arm relates to power and/or fit?
Oh, I may sound confident, but don't forget this is all speculative, as I don't know any more about you and the bike than what you've told me, so there's still plenty of room for me to be wrong!
That said, I really think there's a lot of dogma tied up around the issue of bike fit, yet it seems quite obvious to me that the range of successful fitments is much wider and diverse than many would have believe.
To your question about crank length, in general, shorter cranks are better for spinning, as the trade off some mechanical advantage, or leverage, to longer cranks. I would not expect any real issues, and of course if you do find you want longer cranks, while pricey, swapping to 172.5mm is not hard. If you were going from 175s to 170s, I'd be more concerned. Is there any way you might get the shop to do an exchange for you at a reasonable cost?
As far as fit goes, the shorter cranks will place you a little higher on the bike, and will necessitate a taller seatpost, but we're talking a couple mm here, nothing crazy. For crit racing the shorter cranks might buy you a fractionally earlier pedal stroke out of turns, but again, I'd think pretty minimal impact for all but the most seasoned racers.
Again, these are just my opinions, and reality may be different. Others will have other opinions that may be worth considering and just as valid. Keep us informed of what you decide on!