Originally Posted by
due ruote
I live where it's quite flat and tend to do 90% of my riding in a couple gear combinations. I try to set up the drivetrain so that I have an optimal chainline in those gears. To me that makes more sense than going by what's dictated in a manual, although in practice I doubt I am very far from spec.
I am intrigued though by your statement that chainline is the most important measurement on the bike. Can you elaborate? Are you including fit measurements?
Read this:
All About Bicycle Chainline
There is nothing about "fit measurements" when you are talking about chainline. It's a spec, not a "preference".
Chainline determines everything else, from your wheel dish and cassette combination to your crankset and front derailleur. Get that wrong from the start and you will be fighting drivetrain issues. Staying within your preferred narrow gear range to compensate is hardly correct.
Chainline basically sets the measurements for the rest of the drivetrain. Get as close to that as you can, and build the rest of the drivetrain from there.