ShannonM

Gonna be changing cranks on my '85 League Fuji. Going from a 42T single ring to a 45/42/30 half-step triple. The co-op I wrench at has (so far, after a quick look) a few options:

Deore, (I think it's a DX,) with a BB. With a 73 mm BB, so I can't use it, but the spindle length wouldn't change, right?

2 pairs of Sakae CRs, with the neato twisted spider, but no bottom bracket. I've been reading that the bolted spindles for these are pretty unfindable, but if the Bike Kitchen has the right one in the box o' spindles, I'd be good to go. Thing is, the S/R catalog on velo-pages shows three different bolted triple spindles, the D-3SS at 121.5, the D-3T at 123, and the D-3U at 124.5, all asymmetric with all the difference on the drive side. What the catalog doesn't show is which spindle goes with which crankset, so it seems like a "one of these should work depending on the frame" kinda thing. These should be compatible with the Fuji-branded Sugino BB, right? The odds of all three being in the box o' spindles are... not in my favor. And if I need to go to a Shimano cartridge BB, what spindle should I be looking at? Does "it's a Japanese triple, stick a 122.5 in there and you're good" apply here?

Also, is there any non-cosmetic reason to prefer one over the other?

--Shannon

clubman 

My methodology is trial and error but it's quick and easy. Take your frame into the coop, throw some caged bearings in your DS fixed cup, insert your spindles and slip the crank over the end to see if you've got clearance. If it looks good, tighten it up to make sure your small ring has some clearance from the frame. I don't worry about small differences in chain stay clearances between the two sides.

seypat

I think the Sakae CR takes a 121.5. Not sure without pulling it.

ThermionicScott 

An even quicker-and-dirtier way to do it (if the fixed cup isn’t installed) is just to have an assortment of cheap cartridge BBs on hand that you can just thread into the drive side and mount the cranks to see where the chainline and clearances end up. They could be old and worn out but still perfect for this task!

Another tip: if you have one of those frames with a 70mm or 73mm (but still English threaded) bottom bracket shell, you can still use a 68mm cartridge bottom bracket! Just select one that doesn’t have a ledge on the non-drive side cup, and just keep threading it into the shell until it mates up with the main body of the bottom bracket: