I'm building a fixed mtb for winter, and I have no idea about BB's. I have a set of older, early nineties or so 105 doble cranks that I could use(the ones on the bike are severely beat up suntour from the 80's, with the chainrings riveted in place). I've had my LBS build me a wheel with a On One double fixed hub, On One claim that it gives a 50mm chainline, with a measuring tape i measured 51½. Does anyone know what length BB Ineed for this to work?

The BB seems to be nearly shot anyway so a relacement is due. Should be english threaded, I anyone knows old swedish Crescent-brand mtb's please tell me if it's something else.

Edit; throwing in a pic of the wheel for extra pr0n-effect ;-)