I'm learning my way around the mechanics of bikes and learning how to wrench on them. I just ordered the out of print 2012 Kestrel Airfoil Pro because it closely matches the optimal stack/reach measurements that I was fitted for. The bike I ordered comes with 172.5mm cranks and my fit calls for 170mm cranks though, so I'm wanting to change those out. I know there are several styles of bottom brackets out there and I'll need to order the correct crank arms for what is in the bike. The spec sheet simply says the bottom bracket is an Oval Concepts Integrated bottom bracket. How do I find out what bottom bracket I have and what cranks I should be ordering?

Any recommendations on decent cranks would be good as well. Eventually I plan to upgrade to some power meter cranks, but not yet...so I don't want something super spendy on the cranks, just something good. I do plan on putting some rotor Q-rings on whatever cranks I get.

Have you tried the 172.5s? I'd be surprised if you really noticed a difference.

I say this because I'm riding on 170s on my road bike and 165s on my touring bike, and my "optimum" is probably even shorter than that (I'm 5'3" with about a 30.5-31" inseam). I looked into swapping out the 170s because I knee myself in the chest when I ride in the drops, but otherwise I have no problems (and with my Campy gear, it'll be some $600 to swap cranks!).

Then again, I'm a pretty beginner triathlon participant. I won't even call myself a triathlete, so take what I say with a grain of salt.