Forgive me if my forum search failed to provide an answer, but I wanted to ask a question regarding the chainline of a sole source manufacturer of components.

Generally speaking, if one were to construct a drivetrain by using a single manufacturer, does that ensure a perfect chainline? For example, I intend to build my drivetrain (120mm rear spacing) with Miche Primato hubs, cog (and adapter), BB and cranks. I understand that my BB is adjustable - this is more about general applicability than about my build specifically. Perhaps there are few manufacturer's that provide all the components for drivetrain construction? I suppose I can only name Campagnolo and Shimano, but I am sure there are more.

This, of course, does not account for the bb spindle length.

https://www.sheldonbrown.com/chainline.html

Forgive me for my ignorance (again), but why does the Miche chainline measurement read 5.85/5.15? And furthermore, how does this translate to my bottom bracket sizing for use with Miche cranks? The calculation suggests a chainline of 41.45-42.15 Sheldon's database of bottom bracket sizes does not include those made by Miche, but I know they come in 107mm and 110mm. Is anyone familiar with the chainline produced when using the Miche Primato cranks and either of these two bottom brackets? The difference is likely negligible as the bb is adjustable?

To make matters worse, my bike already has the new Miche bb installed, but I am not certain what size it is, as my gf took the bike down to the lbs for me (I am far far away from my bike at present).

Miche Primato cranks use ISO 107mm BB for a 42mm chainline. Miche hubs will match this chainline, nominally, but it depends on the cog you use since the offset in cog is not consistant across brands.

Also:

https://www.bikeforums.net/singlespeed-fixed-gear/103732-miche-primato-bb-compatability.html

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?

MIN, I meant to thank you for your help.

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.

I think this is in reference to whether you would be using a 1/8" or 3/32" cog. The 5.85 is proabably for the 3/32".

That makes perfect sense; thanks.

FWIW, you don't need to keep everything in the same family, but if you do go with a particular brand of cog on your hubs, it's best to stay with that brand throughout the usage of that hub. But with an adjustable bb like Miche's, you could use various different cogs and have a straight chainline.