Photography by Ron Sessions
After days behind the wheel of the 2018 Chevrolet Colorado ZR2 on city streets, freeways, country roads and in all sorts of traffic, we recently jumped at the opportunity to take Chevrolet’s new 4-wheel-drive off-roader on an off-pavement excursion to determine if it really has the capabilities to back up its Baja-ready looks. The Upper Midwest doesn’t offer the picturesque red rock trails you might encounter in the wide-open spaces of Utah or Arizona, but one commodity it does possess is mud. We found an abundance of the slippery, slimy stuff on the often tight, technical and — dare we say — muddy runs at Bundy Hill Off-Road Park near Jackson, Michigan. There, in the company of mostly all-terrain vehicles, dirt bikes and other mud lovers, we put Chevrolet’s new midsize off-road pickup through its paces. Bundy Hill is a repurposed gravel pit featuring partially wooded, mostly narrow trails and steep grades that are not for the weak of heart.
Just a few hundred feet into our off-road trek, the ZR2’s functional rock sliders proved their worth. These are dealer-installed steel tubes running under the rocker panels from wheel well to wheel well. The already tall-riding 4WD Colorado is hiked up another two inches in ZR2 trim, and when climbing up into the cab, the bars are too narrow to step on, but big enough to make your pants dirty. But off-road, the bars did a great job of keeping the rocker’s sheet metal from getting scraped and dented from rocks and other hazards encountered along the trail.
Also immediately apparent was how the ZR2’s wider stance — 3.5 inches greater than the stock Colorado — imparted a stable and planted feel. Yet, the midsize ZR2 was still able to thread its way between boulders and trees that would’ve hung up a full-size pickup like the Ford F-150 Raptor.
The ZR2’s flared fenders house 31-in tall knobby Goodyear Wrangler Duratrac Off-Road tires. We expected the meaty 265/65R17 all-terrain skins to offer tenacious grip off-road, which they delivered in spades. But what surprised us was how quiet they were during our earlier highway testing relative to other off-road tires we’ve experienced. To make room for the big Goodyears, the outboard corners of the front bumper where the fog lamps would be on a civilian Colorado are cut away for greater tire clearance. This also improved the ZR2’s approach angle for climbing steep slopes without snagging on rocks and stumps.
Where underbody contact was inevitable, we were thankful for the beefy aluminum skid plate protecting the radiator, engine oil pan and transfer case. It replaces the faux plastic one and fuel-economy-enhancing air dam under the front fascia on the stock Colorado. The ZR2s we drove in the recreation area also had the bed-mounted accessory full-size spare tire, which got the big tire out from under the truck where it would most likely foul dirt humps, rocks and off-road obstacles. That’s great for off-roading, not so much if you’re using the ZR2 for Home Depot runs.
The ZR2 is the first truck to be factory-equipped with Dynamic Suspension Spool Valve (DSSV) shock absorbers. These fancy-sounding dampers are the product of Multimatic, a Canadian company that produces the exotic Ford GT and high-performance suspension technology for Formula 1, CART and other racing venues. Chevy’s used DSSV shocks with great success the last few years in the Camaro Z28. The spool valves inside the shocks enable customized damping curves at different points in the suspension’s travel. In the ZR2, this tuning made for a relatively firm and well-controlled but comfortable highway ride, while allowing large suspension movements to handle uneven off-road terrain at Bundy Hill without big vertical jolts to the driver and passengers. And the DSSV’s remote reservoirs increase the volume of fluid available to the shocks to prevent overheating during long treks over rough terrain.
Buttons to Push
We encountered deep mud, water crossings, loose gravel, tight tracks through wooded areas (that would have had us folding in the mirrors and praying in a full-size truck) and steep inclines and descents. The ZR2 doesn’t have a Terrain Management System like the Ford F-150 Raptor to fine-tune throttle response, transmission shift points, front/rear transfer-case torque split and such for snow, rocks, mud or whatever type of terra-unfirma you find yourself in. In the Chevy, there’s a 2-speed electric transfer case operated by a knob on the dash to the left of the steering wheel that can serve up rear-wheel drive, automatic all-wheel drive, four-wheel-drive high range and four-wheel-drive low range.
Because Bundy Hill is a tight and technical course, we spent most of the time in 4WD Low. With first gear in the automatic transmission manually selected for good engine braking, low range was particularly effective on steep downhill grades. Another choice in the ZR2 would be to use Hill Descent Control, operated by a button on the center stack. It intermittently pulses the anti-lock brakes so the driver can descend a steep slope without applying the foot brake. But for the rest of the stuff, you’ve got to take charge off the machine and pick and choose which traction aids and drive modes to use for the given situation.
Lock on Traction
We also got a chance to try out the ZR2’s driver-selectable locking differentials. A locker makes both tires on the same axle rotate as if on a common shaft, so even if only one tire on that axle has traction, the truck can move forward. There are plenty of trucks and SUVs out there with automatic locking rear differentials, but driver-selectable locking rears are rare. And no other factory 4WD pickup offers a standard locking front axle.
A steep uphill climb that looked like something a motocross dirt biker might tackle was the perfect challenge. Stopped at the bottom of the hill, we put the ZR2 in 4WD Low range and pushed the dash button engaging the rear locking differential. We took off for the summit with a fair amount of throttle to keep up the truck’s momentum. All was going well until about 30 feet from the top, both rear tires spun and the forward momentum stopped. Looking in the rearview mirror, the bottom of the hill was a long way down, and backing down would be no fun.
Time to apply the nuclear option — engaging the front locker. The locking front differential can only be engaged with the truck in 4WD Low — its button is on the dash as well. Automatic transmission in first gear, we applied throttle. At first, all four tires were straining to gain purchase in the now-loose gravel. Although steering effort was quite high with the front differential locked, oscillating the steering wheel back and forth while applying steady throttle finally got us moving and up to the summit. For the downhill stretch, we switched off both lockers. Leaving the front locker engaged makes the truck want to go only in a straight line, something you don’t need be fighting around tight turns.
The ZR2’s standard 308-horsepower 3.6-liter V6 is a good choice for all-around use, but if you take off-roading seriously, the $3,500 optional 2.8-liter Duramax 4-cylinder turbodiesel should be a big consideration. Our off-road test truck was so equipped. Its modest 186 hp and 9-second zero to 60 might seem milquetoast, but with a locomotive-like 369 lb-ft of torque on hand from just 2,000 rpm, the diesel-powered ZR2’s ability to tractor-beam itself across challenging terrain can’t be denied.
Starting at $41,215, the 2018 Chevrolet Colorado ZR2 certainly looks the part of a Baja-ready off-road trophy truck. And now we know it has the hardware to deliver on the promise, on-road or off.