The 2017 Chevrolet Colorado ZR2 should be equally at home going off-road or driving around town, thanks to special shock absorbers that have been used in Formula 1 racing and just four other production cars before this. The shocks use multiple chambers that are tuned for off-road driving on rocks where long suspension travel is necessary, and on paved roads where comfort is important if the Colorado is to be used for day-to-day driving. The ZR2 edition was unveiled this week at the opening of the Los Angeles Auto Show.
The Colorado ZR2 uses a shock absorber technology called DSSV, or Dynamic Suspensions Spool Valve, damper technology, developed by a Toronto engineering firm, Multimatic. It’s Chevy’s entry in the resurgent market for midsize pickup trucks.
The suspension on most cars comprises a spring at each wheel that holds the vehicle up (the black coil in the adjacent photo), and a damper, or shock absorber. When the car hits a bump, the spring compresses then rebounds. (Technically, the spring is the component that absorbs the shock.) The cylindrical shock absorber has a piston, or valve, inside. Holes drilled in the piston let the shock absorber fluid flow through the piston, then back again, and damp (not dampen) the oscillation of the springs. Bigger holes let the fluid flow through quickly and make for a smoother ride. But the suspension might reach the end of its travel and the vehicle bottoms out (not good for the car and your spine on a bumpy unpaved road at speed); smaller holes resist resist motion better at the expense of a comfortable ride. That’s the case with the most common shock absorber, using what’s called a deflected disk valve.
The DSSV shock absorber uses a precision-machined spool valve instead. Chevrolet says two spool valves (per shock absorber) are tuned for a pliant ride for on-road conditions and for off-road use under extreme conditions (that is, not just driving 10 mph on a dirt road). At the front wheels, a third cylinder deals only with suspension rebound, extending to full height after hitting a bump. That gives the ZR2 four force-velocity curves (velocity of the shock absorber piston) for tuning versus two for a traditional shock, six curves for the front wheels. The Multimatic shocks use aluminum bodies for heat dissipation and to reduce the vehicles’s weight.
Chevrolet said the Multimatic shocks make more sense for the on- and 0ff-road personality than the Magneride shocks pioneered by GM’s parts supplier affiliate Delphi 15 years ago; Magneride shocks control stiffness by charging metallic particles in the shock fluid. When angled or turned sideways, the shock can go almost instantly from soft to firm to stiff. The Multimatic DSSV shocks are mechanically controlled; no electronics involved.
For the ZR2 introduction, Chevrolet built a miniature off-road obstacle course at a run-down warehouse on the edge of LA’s arts district. (Parts of the DiCaprio-Damon-Nicholson 2006 movie The Departed were filmed there.) I rode shotgun in a Colorado ZR2 with a diesel engine. There were large speed bumps where front then rear axles were stressed, alternating bumps where each wheel was affected, a simulated railroad crossing (more like a launch pad), a hill climb with rollers placed so traction fell from four to two wheels to one, and offset obstacles. With the speed bumps, the ZR2 hit hard as the front shocks compressed and I expected to hit my head on the roof on rebound, but it never happened. Between the obstacle sections on the dirt-and-packed gravel parking lot, the ZR2 felt as docile as a pickup not intended for serious off-road work.
The hill climb ramp was so steep — 30 degrees of elevation — that the Colorado’s big hood obscured not just the ramp but even parts of the evening sky. When we started to lose traction, my test driver stopped briefly and pressed a button (photo right) under the center stack head unit that locked the front wheels. When the rear wheels started to slip, he pressed the adjacent button and locked them. When a third set of rollers made all but a single wheel slip, he locked front and rear wheels and we effectively did a single-arm chin-up to reach the top of the ramp.
Oddly, the Colorado did not have a front camera, something that has become popular for trucks that go off-road. It beats having the passenger getting out and telling you whether or not you’re headed straight when going up a hill. As with any other-road vehicle, you’ll need a guide to see when you’re going over big individual rocks unless you consider yourself lucky. As Car and Driver editor David E. Davis once noted years ago: Four-wheel drive means you can go farther in the woods before you get stuck.
Chevrolet’s goal is to build a premium midsize pickup that is equally capable of going off-road, carrying a payload, or daily commuting. There are cab configurations that make both front and rear seat passengers comfortable on longer trips. The ZR2’s only compromise is that it will carry a noticeable price premium. Pricing won’t be set until just before first shipments in a couple months.
The ride height was raised two inches, the track (width of the centerlines of the wheels) increased 3.5 inches, it was outfitted with 31-inch (tire not wheel) diameter Goodyear Duratec off-road tires that will be noisier on paved roads, skid plates were added, and the front bumper was reshaped to avoid getting hung up approaching obstacles. You can even order a kit to move the spare tire from under the truck to the cargo bed. Inside, the traditional Colorado options are available, including 4G LTE Wi-Fi.
The new generation Colorado is the second best-selling midsize pickup, behind only the Toyota Tacoma, and may hit 100,000 sales this year. (The bigger Chevrolet Silverado pickup has five times the sales.) Midsize pickups are experiencing a comeback in sales and most models have been refreshed or fully renewed in the past two years: Tacoma, Colorado, Nissan Frontier, Honda Ridgeline, and GMC Colorado (essentially similar to Colorado). Compared to passenger cars, these midsize pickups are pretty full-size with lengths that can go over 200 inches with crew cab or long bed variants.
The Colorado ZR2 appears poised to be the single pickup truck off-roaders need that will also keep family members happy when driving on road. According to Mark Reuss, a GM executive vice president, “You can go rock crawling on Saturday, desert running on Sunday, and comfortably drive to work on Monday.”