Originally Posted by
UmneyDurak
OK, so distance from DT to middle of outer ring is 35mm. Circumference is 115mm, so radius is 18.3, so total distance is 53mm. So it doesn't seem to be too far inward...
Sorry for the delay. So chainline is OK at least at the crankset, but the chain still seems to be coming from the outside. Let's continue the process of elimination.
Find a straight edge at least 18" long. Place it against the face of the outer chainring on a secant, and extend back to the cassette. Using the 53mm chainline +2mm for half the thickness of the ring, the straight edge should hit the rear end 55mm from the center. Note which sprocket it lines up with, subtract 55mm from half the width of the rear triangle, and that should be the distance to the inside of the right dropout.
I'm guessing that you may find the distance to be more than predicted which means the entire rear end may be offset to the right (there may be another reason for the error, but it's rare these days).
Do that then come back for the next step.