DETROIT – When three truck builders – Randolph, Reliance and Rapid – merged to become GMC in 1912, the brand’s range of gasoline- and electric-powered trucks used model numbers between 1 and 12, each denoting payload in thousands of pounds, or how much weight could be loaded on the rear.

Today, the labels “½-ton”, “¾-ton” and “1-ton” are still used industry wide for fullsize pickup truck classes despite their having little connection to the trucks’ capabilities. For 2013, a GMC Sierra 1500 “½-ton” has a payload capacity that ranges from 1,550-1,940 pounds – considerably more than the 1,000 pounds once implied. A “1-ton” Sierra 3500HD can haul up to 7,215 pounds; almost four times the 2,000 pounds its moniker suggests.

“The payload-based naming convention for pickups existed right from the beginning,” said General Motors Heritage Center Manager Greg Wallace. “The ½-ton, ¾-ton, and 1-ton models became most popular with retail customers over a few decades, not just for GMC but all manufacturers. While payload capacities have grown since, those three names stuck.”

As with payload classifications, GMC helped pioneer other naming conventions for pickups. In 1967, GMC was the first company to use 1500, 2500 and 3500 to designate its three truck models, numbers that were based off the first segment of vehicle identification numbers, or VINs, and denoted hauling capability. Those numbers remain an integral part of the GMC naming strategy and every current fullsize truck sold by an American automaker uses numbers starting with 15, 25 and 35 to denote the three classifications.

The Sierra name became standard for all GMC fullsize pickups in 1989 after being used for various upscale trim packages through the ‘70s and ‘80s. The 2013 Sierra 1500 represents the core of GMC’s truck business, while the purpose-built Sierra 2500HD and 3500HD models are some of the most-capable pickups ever produced, with class-leading maximum payload.