We drive a 2004 Volvo 630 and pull a Mobile Suite. Truck weighs about 15,000 and the trailer about 17,000 for a 32,000 pound total. Driving about 62 mph with RPMs at 1300 we get 9 mpg.
I drive a 2007 Beaver Patriot Thunder 45' with a 525 HP Cat and tow a Hyundai Santa Fe. Total combined Weight about 50,000. MPG 5.5 no matter what speed (up to about 70 MPH) and around 1450 RPM.
PARADISE AIN'T CHEAP!!!
