Originally Posted by
Dhorochokaro
For the sake of consistency, I will be using the Miche cog. Now, let's assume the installed bb is 110 mm, thus yielding a front chainline of 43.5mm. Is it plausible to use some sort of rear spacer for the 1.5 mm? In this case, I will use the adjustable bb to straighten the chainline, but what if the bb were not adjustable? Do we just figure that the 1.5mm difference is acceptable and pedal on? This inconsistency is the type of thing that eats at my insides - why build a bike with an imperfect chainline?
You can use a BB spacer (available at your LBS or loosescrews.com) to dial in your cog chainline. I have used up to 2mm but beyond that you risk losing thread engagement rendering it unsafe.
Be sure to measure your chainline with vernier calipers prior to using any spacers because the real chainline may not agree with the nominal chainline.