Jay, I'm also running a BFG 155-80-15 and my take on mounting it is this: My local mc shop tried to air it up with no success. (a number of times) Could not get it to bead up all the way around, so the next day took it to my local tire shop and in approx 5 seconds it was mounted. He claimed that the lubricant he uses also played a part in that.
I talked with both and the conclusion was that the tire guy had a large compressor and larger dia. air hoses so lots of air went into the tire very fast and popped it right away.
When I get my bike back on the road, I'm going to try running 45psi, right now am running 39psi.