Aside from needing but a few millimeters of clearance between the pedal-end of the cranks and the chainstays, the actual space there can vary quite a bit depending on the frame's design, and other considerations to spindle length usually prevail.
Spindle length (chosen from what's actually available) should thus be determined by chainring clearance (a couple of mm minimally), chainline, arm clearance and symmetry of pedals about the bb. Note that chainring size can affect clearance at the chainstay, something to consider if you'll likely be changing to a larger inner chainring. I eschew measuring chainline directly in favor of sighting down the sides of the large chainring back to the freewheel.
David Snyder Auburn, CA usa
> A photo of the crank on the BB caught my attention, leading me to a
> general question. How much clearance between left crank arm and
> chainstay do you expect when you select a bottom bracket, and how much
> clearance to you allow on the drive side for chainwheel and crankarm?
> Harry Travis
> Washington, DC