I pulled a 40' bus last night. What a horrible pull. I was about 40k gross. On the flat I could pull 55-60 mph. That was holding 1200-1250 piro 35 psi and 200 -210 water temp. Worse the hills really sucked. One hill I toped at 40 mph. The whole drive was 70 miles. :{ But at least I didn't get caught. 
