Alrighty then, I replaced the crank on my 2005 Giant Rainier because the bottom bracket went all to hell and the LBS had a good deal on a Shimano BB and crankset. So now I have the crankset from my Giant (Truvativ ISIS). I'm still in the phase of picking parts for my winter commuter, a 1993 Raleigh M50, and in order to save some cash I plan on getting another ISIS bottom bracket and using my crankset from the Giant. Nashbar has a house brand ISIS BB for cheap, but you have to specify size. How can I determine the size of BB I need. The crankset has 3 chainrings if that helps.
Thanks fellas, you have no idea how much you've helped me so far.