Once upon a time, a 20,000 lb towing capacity was considered a lot for a one ton pickup (e.g., F350, 3500). Times have changed. The 2013 Ram 3500 with dual rear wheels is rated to tow 30,000 lb. via a fifth wheel trailer.
How'd they do it? A Cummins diesel with 850 ft lb of torque, a new frame, upgraded Aisin transmission, and other upgrades. Hopefully, they upgraded the brakes, too.
Read more about the 2013 Ram HD pickups here
http://www.allpar.com/trucks/ram/2013-heavy-duty-pickups.html
How'd they do it? A Cummins diesel with 850 ft lb of torque, a new frame, upgraded Aisin transmission, and other upgrades. Hopefully, they upgraded the brakes, too.
Read more about the 2013 Ram HD pickups here
http://www.allpar.com/trucks/ram/2013-heavy-duty-pickups.html