450lbs bike + 210lbs driver = 660 lbs
660lbs/39psi ~= 17 squareinch.
Of course its not a fair equation for front/rear distribution*, and that for me is the rear pressure, but if you try to keep this virtual contact patch at 17si for grip and shape, heating and wear, the weight you intend to put should dictate the pressure. Simple. (all luggage can be weighted separately and assumed to go straight to rear wheel)
*The front pressure is a few psi below rear since we dont quite know the proportion, but you could find that easily rolling each wheel on a body scale while sitting on the bike (might want to try using front and read stands if they are secure enough).
dddd screwed with this post 04-21-2013 at 02:24 PM