Optimum (-8) Tire Pressure...
Darryl, asking for an optimum tire pressure is like asking what's the best primer... everyone has a different experience and opinion. That said, my personal experience is that 45psi is right for my bird. My suggestion is that you start at 35psi and test for yourself. Then, using +5psi increments, test again until you have tested at 50psi. Try each pressure on different surfaces. Upon completion of this exercise, you will be awarded a Certificate of Completion and you will have determined the optimim tire pressure for YOUR bird. Hope this helps.
Have a Great Day!