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Discussion Starter · #1 ·
This is a bonehead question.

I'm quite comfortable wrenching on any bike part except forks (which are also 100% confident as long as I have a procedure to follow). But I have zero experience with bottom brackets made after y2k. And there are a million standards that make no sense to me.

So, on my '97 frame, I can adjust my chainline because the BB is a few mm wider than the frame threads. I guess it is BSA standard? Anyway, on the drive side the BB is "aligned" with a 3mm spacer (it was installed this way 24 years ago), and on the non-drive side the threads bottom out with 3mm to go, and there is a viton o-ring sitting over the exposed threads to protect them from grime and dirt.

Life is good.

BUT, if I wanted to update the cranks, that means getting a new BSA BB (I think?) and matching crank with the right spindle diameter. OK, so far so good, I think.

Here is the bonehead question:

The cranksets all specify the chainline. Is the BB set up so I can add a spacer or otherwise move the bearing by a couple mm as needed if I need to shift the chainline? Or is the chainline whta it is, zero adjustability in the BB, and I need to be DAM sure of the chainline I need, because it is set in stone and that is all I am gonna get out of it?

(if it helps, I can cut custom spacers from aluminum on a lathe, it's an easy job. I make my own shock bushings and other parts all the time)
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