From my understanding, the max tire pressure may not always be the ideal one. Like what vanole said, there are a lot of variables that need to be determined to get the ideal tire pressure for your RV like the weight of the RV with and without any passengers. You can find the recommended tire pressure for your RV in the manual, or you can get a tire pressure chart from the tire manufacturer. Many have these online so you can download it from the Internet. If it's not available, ask your tire dealer.