Measured H2O truck today, and the rears are 56" apart as others have stated. The axles are 59-60" at the brake backing plate flange, and appear to be the same as other 5 tons. The torque rods are 25" long and all six are the same. The 56" axle spacing also means that the drive shaft between the axles is longer too. The big difference in bridge trucks are the spacers used on the front and rear hubs, the special long wheel studs that locate the spacers, and the very deep dish 10x20 wheels that came only on these special trucks. If you look close at the front hub in the attached photo, you can see that the wheel is offset out away from the actual hub surface. Without these spacers, the front wheel/tire would hit the tierod end. The rear has much thinner spacers (about 1½" thick) which we installed on the outside of the hubs when we flipped them. Front spacers still make the front track just a little bit wider than the rear, but you really can't see it.
Had to drive the truck back home to change a rear tire with a slow leak, and it still is way slow, can't get it to barely 50 mph down hill on to a flat section. Tried to readjust carb linkage to make sure that it is wide open, and turned the gov. screw in 1½ turns. Still way slow on the ride back to the jobsite. Got the rear tires to spin in sugar sand with no load on and no air pressure to engage the sprag. All 4 rear tires spin together!Truck jumped up and down about 8-10" and still clawed it's way out of the sand. May have rear lockers. Still have to do the jackup test.
The housing is "specific" to the bridge truck also as the axles themselves ARE longer than the 5-tons. I was told that the bridge truck assembly is 4" longer overall than the 5-ton. I have pulled a set of my duals and loaned to a friend, and installed correctly with the spacers positioned right, the tires touched the springs ( my 14:00's) on his standard 5-ton. He wanted to see what his truck would look like and ride with my tires and spacers, but they would not fit.
Rear Tandem Spacing
