1997 GMC Sonoma Owner's Manual - Page 191

If you're using a weight-carrying hitch, the trailer tongue (A) should weigh 10 percent of the total loaded trailer weight (B). If you're using a weight-distributing hitch, the trailer tongue (A) should weigh 12 percent of the total loaded trailer weight (B). After you've loaded your trailer, weigh the trailer and then the tongue, separately, to see if the weights are proper. If they aren't, you may be able to get them right simply by moving some items around in the trailer. Hitches It's important to have the correct hitch equipment. Crosswinds, large trucks going by and rough roads are a few reasons why you'll need the right hitch. Here are some rules to follow: If you use a step-bumper hitch, your bumper could be damaged in sharp turns. Make sure you have ample room when turning to avoid contact between the trailer and the bumper. If you'll be pulling a trailer that, when loaded, will weigh more than 2,000 lbs. (900 kg), be sure to use a properly mounted, weight-distributing hitch and sway control of the proper size. Thisequipment is very important for proper vehicle loading and good handling when you're driving. Total Weight on Your Vehicle's Tires Be sure your vehicle's tires are inflated to the upper limit for coldtires. You'll find these numbers on the Certificatioflire label on the driver's door edge,above the door latch or see "Tire Loading" in the Index. Then be sure you don't go over the GVW limit for your vehicle, including the weight of the trailer tongue. If your vehicle has the bumper delete option, do not bolt any type of hitch to the close-out panel. The close-out panel will not support a hitch.