I recently had to replace the crankset (essentially arms and chainrings) on my mountain bike & I find that the inner chainring is now too close to the frame to allow the front derailleur to adequately line up with it (regardless of how its adjusted). My micrometer tells me that the new chainring in 5mm further in toward the frame than the one that it replaced. My assumption is that I'm going to need a new bottom bracket with a spindle that is 10mm longer than the current one (assuming that the additional 10mm of length is spread out evenly over both sides, that is). Does the notation on that old BB that reads BC 1.37x24T refer to the threads & is that "standard"?

Thank... Brian