2007 GMC Sierra 1500 III (GMT900) Extended Cab Standard Box Dimensions, Size & Specs

The maximum gross vehicle weight rating (GVWR) of the 2007-2013 GMC Sierra 1500 III Extended Cab Standard Box is 2903 kg (approximately 6,400 lbs). This means the combined weight of the truck, passengers, cargo, and any trailer tongue weight should not exceed this value. Given its size and engine options, the Sierra 1500 III is suited for moderate towing and payload tasks typical of full-size pickups.

Standard residential garages typically measure about 2400 mm to 2750 mm (8 to 9 feet) in width and 4800 mm (16 feet) in length. With a length of 5844 mm (230.0 inches / roughly 19.2 feet) and width including mirrors at 2029 mm (79.8 inches / 6.6 feet), the GMC Sierra 1500 III Extended Cab Standard Box is generally too long to fit comfortably into most standard garages. Its width without mirrors would fit, but mirror adjustment or folding is necessary to avoid collisions. Height of 1876 mm (73.9 inches / 6.16 feet) is usually not a constraint in garages.

Compared to the predecessor generation Sierra 1500 models, the Sierra 1500 III Extended Cab Standard Box (GMT900) introduced from 2007 to 2013 is larger and more robust. It is longer and wider, providing increased interior space and enhanced cargo volume. The design also gained in ride height and ground clearance (226 mm / 8.9 inches), contributing to better off-road capability and presence. Overall, these changes reflect GMC’s focus on offering a more spacious and versatile full-size pickup.

The luggage capacity behind the rear seats of the 2007-2013 GMC Sierra 1500 III Extended Cab Standard Box is approximately 1718 liters when rear seats are folded. This capacity makes it competitive among full-size pickups with extended cabs offering a balance of passenger and cargo space. While trucks with crew cabs may offer more passenger room at the expense of cargo bed length, the standard box configuration here maintains a usable cargo bed suitable for both tools and recreational gear, on par with models like the Ford F-150 and Chevrolet Silverado from similar years.

The GMC Sierra 1500 III Extended Cab Standard Box has a ground clearance of 226 mm (8.9 inches). This elevated ride height improves off-road capability, enabling the vehicle to navigate rough and uneven terrain more effectively than lower-riding trucks. It also helps prevent damage to the underbody during off-road driving or heavy-duty use. However, higher ground clearance can slightly affect aerodynamics and fuel efficiency but is generally beneficial for a pickup designed for versatility and rugged use.

This generation GMC Sierra 1500 Extended Cab Standard Box comes fitted with 7.5J x 17 rims paired with 245/70 R17 tires. These tires are well-suited for a mix of on-road comfort and light off-road capability, providing a good balance of grip, load capacity, and ride quality for a full-size pickup of this weight and size. The 17-inch rim size is common for trucks of this era and ensures availability of a wide range of replacement tires.

The extended cab configuration provides additional rear-seat space compared to a regular cab, but less than a crew cab variant. The rear seats in the extended cab are smaller and often feature smaller doors or half-doors for rear passenger access, which may affect convenience. However, when rear seats are folded, it provides a luggage capacity of 1718 liters, making it versatile for carrying tools or cargo. Crew cabs prioritize maximum passenger comfort with full-size rear doors and more legroom, but may have slightly reduced cargo bed length.

The GMC Sierra 1500 III Extended Cab Standard Box is praised for its solid build quality and comfortable ride, benefiting from GMC's focus on durability and refinement. Its suspension setup and ride height provide both on-road comfort and off-road ability. Compared to similar pickups like the Ford F-150 or Ram 1500 of the same era, it is generally competitive in ride comfort and cargo utility, though some competitors may offer more advanced technology or slightly better fuel economy. Overall, it performs very well as a versatile full-size pickup.

The 2007-2013 GMC Sierra 1500 III Extended Cab typically came with several engine options including V6 and V8 variants, such as the popular 4.8L V8 and 5.3L V8 engines. These engines provide a good balance of power and torque for towing and hauling duties. Towing capacity varies depending on engine and configuration but generally ranges from roughly 3,400 kg to over 4,500 kg (7,500 to 10,000 lbs), making it suitable for a wide range of trailers including boats, campers, and utility trailers.