Ha Ha Ha - I was just reading sheldon brown's help page and trying to figure out what size BB I need, when I thought: I'll ask the chainlink! What timing!
My problem is similar, but first here's an answer for J Mills - http://sheldonbrown.com/bbsize.html - scroll down to the photo's; he shows you how to measure the chainline.
My problem: is it 68, 70, or 73? I've got a 1980 Raleigh super record; getting ready to upgrade form stock cranks (running fixed on just the 52 ring) to a Pake 1/8" track crank. Sheldon said Raleighs use either 68 standard, or 73 oversize. Anyone have experience with this?
And for the funny stories, this isn't hilarious, but when I was building my bike I stripped it down and lost the little bit of hardware that holds the rear brake cable for centerpull brakes. I searched all over my workspace. At that time I was going to make it a freewheel. After much debate, and a winter of building, I decided to just go fixed so wouldn't need that piece anyway. So the bike's finished as a fixie now, and what turns up? Yup, you guessed it.
Thanks Bikefreeek, I was afraid I'd be stuck with trial and error. I had assumed it was a 68mm, but the BB I got (long story, 103mm so probably won't work anyway) looks a lot smaller in diameter than the BB shell - so unless there's a lot of thickness to the shell, I can't see the 68 working.
One of the main reasons I'm changing cranks, is that mine don't have a "spider", the 52 ring is crimped to the crankarm at the center and can't be removed. Only the smaller ring has chainring bolts holding it to the 52, and that one's been removed. Is there a difference in BB shell of the raleigh 3 speeds you speak of and the 10(?) speeds from the early 80's? I took off suntour derailleurs, no archer 3 speed hub on this one. Just want to make sure I know what you're talking about..theres so much good stuff.