Any question answered...

I have a MTB ext.BB chainset going in a 73mm BB. Do I need a 2.5mm BB spacer? Cranks won't tighten up to the face so I suspect they do need one.

Hmm, something isn't right then. It's a Truvativ Stylo xc crank. Shouldn't be 83mm.

Worked out where I was going wrong. I was using a Shimano BB with a Sram crank. Why are Sram designers such dicks with compatability? Too close too see a difference, too different to bodge