2down...I totally understand the physics and I would not air down my 19.5's. Your explanation is spot on as far as I am concerned. I still would like 805 to explain his statemement or maybe he should relate the issues he had and under the circumstance he endured those issues, so we all may be enlightened. It may be helpful to me and those of us who drive 19.5's so we can avoid those situations. So far I have not had any issues, but his expereinces may enlighten me on how far I can push my rig. Maybe I was not plain enuf in my original post request. Happy driving to everyone.