Hi dieseldog. Do you air down and run back roads with the 15's? Any issues? Looking for your experience...I never have.
I have some stock 15" powdercoated steelies that a buddy gave me. I would not hesitate to run 33x15's on them on my BJ42, full street pressure, as it does not go off road any more. Here, we typically have long sections of backroads to travel to get to a trailhead. Standard practice is to air down as soon as the pavement ends, and speeds are not crawling to the trailhead. I would and have run at 20lbs on backroads in the 16" tires. I would not feel as confident in the equivalant 15".s...not tall skinnies anyway.
gb