Getting a straight chainline... road double on FG
okay, i feel like a dink for asking this here since i know that it has probably come up a million times- but i can't figure this out and it's making me go insane.
I want to buy the cheep ultegra crankset that i keep seeing all over ebay and such (http://cgi.ebay.com/SHIMANO-ULTEGRA-...QQcmdZViewItem
which means that i have to get an octalink BB...
So! I have an IRO rear hub (36.0, according to sheldon) and a Surly Cog (good for another 5.07?) so by my math i need a 41.07mm chainline?
If i get the octalink 109.5 V1 blah blah, i get a chainline of 43.5.
Does this math add up to good, or bad? Is being 2mm out terrible? When you measure a road double, you're suppose to measure the middle ring, but i'm pretty sure i want to use the outer ring, so does this all not mean anything anyways?