2010 GMC Sierra 1500 Crew Cab Owner's Manual - Page 441

Weight of the Trailer Tongue The tongue load (A) of any trailer is very important because it is also part of the vehicle weight. The Gross Vehicle Weight (GVW) includes the curb weight of the vehicle, any cargo carried in it, and the people who will be riding in the vehicle as well as trailer tongue weight. Vehicle options, equipment, passengers and cargo in the vehicle reduce the amount of tongue weight the vehicle can carry, which will also reduce the trailer weight the vehicle can tow. See "Loading the Vehicle" for more information about the vehicle's maximum load capacity. Trailer tongue weight (A) should be 10 percent to 15 percent and fifth wheel or gooseneck kingpin weight should be 15 to 25 percent of the loaded trailer weight up to the maximums for vehicle series and hitch type shown below: Vehicle Series Hitch Type 1500 Weight Carrying 2500HD/3500 Weight Carrying 1500 Weight Distributing 2500HD/3500 Weight Distributing Maximum Tongue Weight 272 kg (600 lbs) 453 kg (1,000 lbs) 499 kg (1,100 lbs) 680 kg (1,500 lbs) 5-65