I have a 2005 Bianchi Pista. I use it every day as my main transportation so I like keeping it in tip top shape. My old cranks and bottom bracket were worn out (the cranks would slowly loosen over time and work out the bolt), and also the rear hub went bad, so I just bought a new IRO rear wheel, IRO 110mm bottom bracket, new IRO 165mm cranks, and a new KMC Z410 1/8" chain.. According to IRO's website, the 110mm BB + IRO crank combination gives a 42mm chainline.
I put the parts on my bike today and I measure a 47.5mm chainline on the front and 41.7 on the back. Why is my front chainline over half a centimeter off? The bottom bracket is installed the right direction, and everything is tightened down properly. The cranks came with a 46t chainring which I haven't touched.
I am not experienced dealing with chainline issues... what's my best course of action? Replace the bottom bracket? Contact IRO? (they do say the cranks + bottom bracket combo should give a 42mm chainline...)