Originally Posted by masterli

Thanks I feel closer to understanding and solving this. I measured my chainline and it is closer to 42.5mm. To reference my measuring I checked my wife's (trek fx 7.2 WSD 2013) and it's about 48mm. No shim in her derailleur for what it's worth. I don't know if I was duped (that's for another thread) but the whole drivetrain has been changed from stock to components from mid 2000's as far as I can tell. The derailleur is a Shimano
Deore XT FD-M761 and crankset is a Shimano Biopace-SG B48. Well the biggest ring says biopace-sg, I don't know for sure about the inner ones. Not sure if it matters but I can tell they're all elliptical. Is the only measurement the number of teeth? By my count it's 48/36/28. From the specs the derailleur is definitely for a bigger seat binder and I can't clamp it down without shims.

I still can't determine whether these are incompatible. Can I just use a spacer in the chainset to make it work? Can I just put in a new derailleur or chainset to make it work? I'm going for a cheap solution that would last at least a year. I've decided to stick with the bike if it makes financial sense, learn more about what I like and don't like before spending a few hundred on tweaking this or going with something different. Thanks for the help.