Bison belong on the open prairie running through tall grass, over hills and scrub. That's the picture many of us have of the American High Plains thanks to countless western movies. Chevrolet concocts that imagery for the Colorado mid-sized pickup truck through a partnership with American Expedition Vehicles (AEV).

The folks at AEV basically took a standard Colorado ZR2, already replete with off-road gear, and added a bunch of boron steel and a big buffalo logo and called it a Bison. It's a factory-made rig, with parts being put on by Chevrolet but with the added off-road gear being provided by AEV. It makes for an extremely capable off-road rig. Enough so that it can (almost) play with the big boys with "Rubicon" and "Raptor" in their names. It's certainly a contender against the Gladiator.

After seeing the Bison unveiled, we couldn't wait to get our hands on one. We got the best setup we could have asked for: the ZR2 packaged AEV Bison in crew cab with the diesel engine. Off-road enthusiasts will understand why having that low-lugging, high-torque diesel is ideal.

Of note are the changes made with the Bison package. It adds about US$5,500 to the price of the truck and most of the upgrades are shielding. Basically, the Colorado gets boron steel skid plates protecting just about everything underneath the truck, including the transmission, transfer case, fuel tank, both differentials, etc. It also gets boron steel AEV bumpers, AEV-spec'd wheels, added badges, interior stitching and badges, wheel flares, and a more aggressive grille.

That may not sound like much, but the ZR2 package for the Colorado already has larger 31-inch tires (265/65R17 Goodyear Wrangler DuraTracs), and a much beefier suspension for the 4x4 setup that results in a longer reach, and locking differentials. Making it the only Chevrolet truck which has both front and rear locking diffs.

AEV says that the use of boron steel means that the skid plates and bumpers can take a bigger beating and still bounce back clean. They're more resistant to gouging, have a high yield strength that allows them to return to shape after bending, and a low mass. The lattermost point means that the AEV boron plates aren't too much heavier than the aluminum-alloy plates they replace on the ZR2.

The whole AEV setup, wheels and all, adds only about 200 lb (90.7 kg) to the vehicle's overall weight. The diesel upgrade also adds another 200-ish lb to the truck. Chevrolet tunes the Bison's suspension spring rates to compensate for the added weight.

To make sure that the truck was competitive against the new Gladiator, and the Jeep name in general, engineers from both Chevy and AEV tested the rig extensively on the Rubicon trail in Moab, Utah. On our own in the wilds of Wyoming, we tested the Bison on a favorite hill that requires a lot of clearance, muscle, and shock-taking to traverse.

Going down the hill, the Bison "ass-smacked" a few times because of its less aggressive departure angle in the back, but otherwise had no problem getting down the rocks. Going up? Not so much. Its lack of breakover clearance meant it couldn't get over those same rocks. The Gladiator Rubicon, we've since learned, also has a similar breakover issue on that same hill. It's a matter of wheelbase and clearance.

The benchmark for this kind of off-roading is the current-generation Jeep Wrangler, which has 37-degrees for breakover and a ground clearance of 10.8 inches (27.4 cm). By comparison, the Bison has about 9 inches (22.9 cm) of ground clearance and the Gladiator has 11 (27.9 cm). Both have longer wheelbases, resulting in shorter breakover angles (23.5° for the Bison, 20.3° for the Gladiator Rubicon). The Bison was very close to being capable of going up our hill, but prudence said not to try for fear of high-centering the truck.

Pricing for the Colorado ZR2 Bison starts at $43,995. Getting up to the $50k mark is easy though, when adding options and the diesel engine. Given that the Gladiator Rubicon without a diesel but with top-end specifications can also easily approach those figures and the Ford Raptor is well over those numbers in most builds, the price isn't as much of a shocker.

The 2019 Chevrolet Colorado ZR2 Bison is a wonderfully-designed midsize off-road powerhouse. It looks aggressive and lives up to those looks when put to the test.

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