The 9R22.5 tires are readily available, and priced like the big truck tires they are, but they do last a long time, not over priced, but not cheap either. The problem comes with the wheels, they are available, but not new. It takes some looking to find used ones, but they are not expensive.
This Tech tip explains your options
http://www.stovebolt.com/techtips/wheels/I don't think narrowing the P30 axle for use on the P30 chassis is an option, but I have not measured and figured to see for sure. Like you suggest, the front suspension may be a problem.
Say you narrow the axle, then move the springs and spring hangers in a similar amount, the frame is still wide and the tires rub it in a turn. Can the whole front section of the frame be narrowed along with the axle? If you have a complete P30 handy can you take some measurement and do some figuring?
The rear axle can probably stay the same. My rear axle is a Dana 70HD from a P30, and outside of the duals is about 7', very narrow I think for still having duals, and it will look good with a flat bed just as wide as the rear tires are.
Thanks, I have had a good time working on my 2 ton, and continue to, but if I could only get it done it would be more fun...
Grigg
