I have a 2010 Dodge 3500 Mega Cab Dually 4X4 with 6.7 ltr Cummins Diesel. I pull a 2011 3950 Cyclone HD Edition. With 2 680 lb. Harley's in the garage, and gross vehicle wt nearing 17,000 lbs, my Dodge will accelerate up 5 & 6% grades. And on flat ground towing, I'm averaging 10mpg. With the...