Bridge Truck Tire/Wheel Update
Finally got the rear tires off the truck to look at the hubs and wheels. The rear hubs are not the same as the "normal" 5 ton trucks. They have a much thicker flange (2"+) and much longer studs (4"+) than the standard hubs, so the 1400x20 tire/wheel combo does not hit the frame or springs. It does look like the hubs could be flipped, with the wheel mounting surface ending up about flush with the end bolt circle where the axle bolts on. Still, with the super offset for these wheels it looks like the tires still will not end up in line with the fronts.
Also took off one of the front tires, and the front hubs do not use a spacer, the hub has the spacer built in, with studs over 6" long. No way to remove this spacer or even flip it over, other than a complete replacement of the hub. The front hub will not interchange with the rear as shown in the parts book. As built, the face of the wheel when mounted, is outside the end of the hub on these trucks with a wheel track (outside to outside) on the front of almost 8'. If we used standard wheels on the front, I think that we would be close to the 102" max width and the tires would hang outside the fenders. What is the offset for a standard wheel? I will measure the bridge truck wheels tonight. Thanks for the responces.