I learned something new this past month.... The Cutter is 10 years old and has had three tire blow outs since we first purchased the rig in 1998. At 10 years, we needed to replace the remaining tires and ordered new. The tire dealer guessed we blew the others. He told us the chassis' are typically shipped to the factory with 35psi, are built on. The increase in weight compromises the tire walls and even after the pressure is increased to the correct amount, the tire walls are already damaged.
We never had any idea this was the problem.
Now we have new tires all around and feel much more secure.