Originally Posted by MacG

Not to hijack the thread, but I have a similar question.

I have a set of Sugino RD's in the mail right now ($54 at aebike right now if you need some) and am trying to learn about bottom bracket spindle lengths and stuff. I just bought my first set of "real" wheels, so I'm running a Formula flip flop hub in the rear with Dura Ace cog and lockring.

Up front, I have a cheap road double that has been modified and hacksawed to turn it into a single using the inner ring position. The frame is an early 1980s Raleigh 10 (I think) speed road bike with the 126 dropouts respaced to 120 by bending the stays in a controlled manner. I'm using the BB that came with the frame, after cleaning and regreasing it. This actually gives me a very acceptable chainline with the inner ring position of the modified road double, but I'm guessing this won't be right with the RDs.

It's my understanding that Formula hubs use a 44mm chainline as measured from the center of the frame/hub. Measurements with a caliper supports this in my case. What do I need to know about the frame to get the right bottom bracket for this setup? I'm sure it's a pretty common configuration for a conversion, but I keep finding conflicting reports on BB length. I'd like to put a ~$20 cartridge BB in to get away from the cupped BB, but I don't want to get the wrong BB if I can help it.

Anyone have advice or can tell me what to measure and how to find out what will give a proper chainline?