We recently had the opportunity to drive the concept truck in Park City, Utah. The GMC Sierra All Mountain, affectionately referred to by our guides as SAM, is based on the GMC Sierra 2500 platform with the gas 6.0-liter V-8. There are actually five SAMs in existence across North America right now, in All Terrain X or Denali trims. Some SAMs have the 6.0-liter gas V-8, while others have the more grunt-worthy and powerful turbo-diesel 6.6-liter Duramax.
The most noticeable upgrade to the SAMs are the Mattracks 150 series tracks in GMC Red. These tracks add about the same amount of ground clearance to the truck as a set of 40-inch tires would, which would also require a 6-inch suspension lift. The tracks are 16 inches wide and have a contact length of up to 59 inches in soft terrain. That provides a contact patch (where the tread is making contact with the ground) of more than 900 square inches in soft terrain, which allows it to float across the snow. To allow these tracks to fit under the truck, GMC added a 6-inch suspension lift to make sure nothing interfered with the truck body or undercarriage parts. Apart from that, the truck has special graphics, a GMC Sierra sports bar, 3-inch step bars, snowboard and ski racks from Thule, underbody lights and light bars from Rigid Industries, external dual pod speakers from Kicker and a soft tonneau cover from Advantage.
During our drive in the 6.0-liter version of a SAM in All Terrain X dress, the first thing we noticed was its massive size, both in height and width. The tracks are much wider than a set of tires would be, and with the lift and tall tracks, it's very tall as well. To climb in, we had to step up use the almost thigh-high step bar. Upon getting into the driver's seat, we were met by the same comfortable interior of a GMC Sierra 2500 All Terrain X.
After getting a short overview of the course, we had our turn to tear it up. We drove across snow more than 3 feet deep, and up and down some steep slopes. It was impressive to see how well the truck could handle the terrain. While I sank to my hips trying to walk on the snow, the SAM drove along without getting stuck, almost floating on the surface of the snow. Even with the tracks on, the truck provided excellent feedback. It was easy to tell exactly what the pickup was doing. The steering was a little bit heavier than a factory truck, and the turning radius was understandably larger, but it wasn't difficult to control by any means. The SAM was pleasant to drive and wasn't fatiguing at all. One thing we wish we could have tried was the Duramax diesel version. The gas-powered SAM pulled through everything we attempted, but it would have been interesting to see how the extra torque of the diesel performed in the same environment. Our guess is that it would have flung the snow even farther into the air.
While GMC has no plans to produce this truck (we've been told tracks like these can cost as much as $10,000 per corner), we have no doubt that there are custom shops around the country willing to build one for the right customer. We think a SAM would be useful for those with remote cabins in the mountains: Having tracks would allow people to travel in a comfortable, climate-controlled environment without spending hundreds of thousands of dollars on a snowcat. One of the greatest benefits of a SAM is that it's easy to switch between street-legal tires and tracks. This potentially allows the vehicle to be used in a variety of environments all year-round, avoiding the need for a dedicated winter vehicle and a dedicated summer vehicle.
Cars.com photos by Mark Williams