Originally Posted by 70sSanO

I really doubt your 120mm spindle will work especially if it is asymetrical and may actually be closer to using 123mm, as far as the DS.

There are a few things to consider. I’m far from an expert on all the ins-n-outs, but you do need to consider the rear dropout width and BB shell width.

Generally, in the 90’s, 68mm is a road width with 130mm dropouts. 73mm is mtb width with 135mm dropouts. In overly simplistic terms, if your dropout with is 135mm the first position cog is out further from the centerline than with a 130mm.

Using a cartridge BB for a 73mm shell should adjust for this and the specified 48mm chainline for the crank. Using a 68x113 BB might move it out more on the DS and give you a 50.5mm chainline. This does make the BB asymetrical in a sense. It is such a small amount it might be moot. Keep in mind the overall 9 speed cassette is wider and pushing the crank out too far does increase the angle on the low cogs.

John

Edit added: Remember, the 113mm spindle has no clue how wide the BB shell is. A cartridge BB is symmetrical and the spindle just sits there. Using the wrong BB for the shell just centers it too far in or too far out.