Do you know if steer axle fender clearance would be an issue since the 305/75 is about an inch wider than the 11R?
The 305/75 certainly give extra capacity over the 11R24.5 H rated tires. As you point out, that would at least take one of the limiting factors out of the equation. I would still be weight limited by the Alcoa wheels which are rated at 7200 pounds each and a max cold pressure of 120 psi. My Bridgestone 11R24.5 H rated R280 has a 120 psi load carrying of 7160 pounds while the Bridgestone 307/75R24.5 at 120 psi will carry 7540 (7830 at 125 psi but that would exceed the wheel pressure rating
http://www.trucktires.com/us_eng/tec...fl/table05.asp).
If the fender clearance isn't an issue, I would think that they would give you an extra margin of safety on the steer axle.
The front axle on my coach has a GAWR of 13,200 lbs so something other than the wheels must be considered by Newell as the limiting factor. I find it interesting that the G rated tires (6610 pounds max) would have limited them to the 13,200 pounds. However, a post from Newell Tech support
http://www.newellcoach.com:591/bboar...d=34612&-find= indicates that they used H rated tires at that time. I wish I knew what was the limiting factor on the steer axle as mine is overloaded when my fuel tanks are more than 1/2 full even though I still have lot's of capacity on the rear of the coach.