Because the ball is closer to the rear axle of the truck.
2010 Gmc 2500 Duramax 853,500 miles - sold
2010-gmc-2500 maintance log
2013 Chevy 3500 LT CCSB, bought at 509,000 miles, now over 674,000 miles
2013 LT CC & Chassis with 9' Hillsboro Aluminum flatbed - under 84,000 miles - sold
Favorite book : The Richest Man in Babylon