Originally Posted by
e_guevara
I think fstshrk is asking "what is the length of the crank that came from your mate's girlfriend?"
If it's a regular size (not an odd size), 170 mm, and your current FSA Omega crank also has 170 mm, and you're not having any problem with your current crank, then you're fine.
Exactly. Check the crank arm on your bianchi to see what the length is. If it is 54/56 I am guessing it will be 172.5, a 58+ bike would be 175 typically.