2007 Hummer H3 Owner's Manual - Page 300

Your spare tire carrier is behind the tailgate. If your hitch extension is too short, the spare tire may interfere with trailer coupling or trailer tongue jack operation on some types of trailers. 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. The trailer tongue weight (A) should be 10 percent to 15 percent of the total loaded trailer weight (B), up to a maximum of 500 lbs (227 kg) with a weight carrying hitch or a weight distributing hitch. Do not exceed the maximum allowable tongue weight for your vehicle. Choose the shortest hitch extension that will position the hitch ball closest to the vehicle. This will help reduce the effect of trailer tongue weight on the rear axle. Total Weight on Your Vehicle's Tires Be sure your vehicle's tires are inflated to the upper limit for cold tires. You'll find these numbers on the Certification/Tire Label located on the B-pillar below the door latch or see Loading Your Vehicle on page 289. Then be sure you don't go over the GVW limit for your vehicle, or the GAWR, including the weight of the trailer tongue. If you use a weight distributing hitch, make sure you don't go over the rear axle limit before you apply the weight distribution spring bars. 300