Inflating tires to the max psi as shown on a tire is not necessarily correct and an overinflated tire can be just as unsafe as an underinlfated tire.
The following is copied from an earlier post...
BTW-Just because a tire is rated at a maximum inflation of 80 psi does not mean they should be inflated to 80 psi if the maximum weight for that tire is not met.
For instance the LT235/85R16 Load Range "E" tire (as used on most newer Montys)at 80PSI has a MAX load capacity of 3042#, at 75 PSI the load cap is 2905# and at 70 PSI it's 2765.
The same size tire in load range "D" with an inflation of 65 PSI carries a max load of 2623#, at 60 PSI the load would be 2485 and at 55 PSI it's 2335.
Here is a PDF link to
RV Load and Inflation Tables