Originally Posted by cadillackid
the uniroyals im running, are a higher load rating and the tire guys recommended running 100..
While a higher load rated tire means you can support more load and run it at a higher pressure there is still good reason to keep the pressure matched to your vehicles weight. Evenness of wear and ride quality are the two big reasons to figure out a proper inflation.
While inflation and load rating for commercial truck tires differ between manufacturers, they really don't differ by a wide margin. Standard truck tires have been mostly... ahem.. standardized ;).
I would trust the plaque that the vehicle manufacturer put inside the vehicle more than the tire salesman. The salesmen know the tires, but they don't know the vehicle. A quick cross-reference from any of the commercial tire inflation tables could help out, even if you changed tire sizes.
For instance if the vehicle information plaque recommends 10r22.5 tires inflated to 80psi for the front axle you can look at a table and see that the front axle is supporting something around 9000lbs. Move to the 11r22.5s and to support around 9000lbs you need somewhere between 70-75psi...
Just sharing what I've learned! It has helped me with ride quality considerably