2008 Pontiac Grand Prix Owner's Manual - Page 265

Weight of the Trailer Tongue The tongue load (A) of any trailer is an important weight to measure because it affects the total or gross weight of the vehicle. The Gross Vehicle Weight (GVW) includes the curb weight of the vehicle, any cargo in it, and the people who will be riding in the vehicle. If there are a lot of options, equipment, passengers and cargo in the vehicle, it will reduce the tongue weight the vehicle can carry, which will also reduce the trailer weight the vehicle can tow. And if towing a trailer, the tongue load must be added to the GVW because the vehicle will be carrying that weight, too. See Loading Your Vehicle on page 4-22 for more information about your vehicle's maximum load capacity. When using a weight-carrying hitch or a weight-distributing hitch, the trailer tongue (A) should weigh 10 to 15 percent of the total loaded trailer weight (B). After the trailer is loaded, weigh the trailer and then the tongue, separately, to see if the weights are proper. The correct weight could be achieved simply by moving some items around in the trailer. 4-31