The Colorado ZR2 Bison has a technologically advanced suspension. Here’s how it works

The secret is in the shock absorbers.

Multimatic has been producing suspension components since before I was born – literally since 1984. And they did a damn good job. Red Bull won four consecutive Formula 1 titles using Multimatic’s Dynamic Suspensions Spool Valve (DSSV) shock absorbers. Since then, five major racing series have adopted them as standard. Currently, DSSV shock absorbers can be found on production cars from Maranello to “Merica” ​​- in this case the Chevrolet Colorado ZR2 Bison.

Believe it or not, the Colorado ZR2 was the first off-road vehicle to use Multimatic’s DSSV shock absorbers in 2017. Previously, they were reserved for sports cars. The Bison adds 12.2 inches of ground clearance and 35-inch off-road tires to the equation; Chevrolet engineers threw everything they had at the ZR2 to make it the meanest, baddest, most capable truck in its class – including the DSSV.

Shock absorbers here work essentially the same as they do in sports cars: a pair of spring-loaded hydraulic valves are pushed through a chamber filled with pressurized hydraulic fluid, and adjustable orifices control the rate of oil flow. However, to account for the enormous loads the ZR2’s suspension will regularly receive when off-road, Multimatic has made a few adjustments.

The biggest change is the bumper, which is exclusive to the Bison model. Instead of traditional rubber bumpers that apply as much force as the pressure applied, the Bison has custom hydraulic bumpers that control the bounce – Multimatic coined the term “Jounce Control.”

Simply put, these shock absorbers absorb more and dissipate less. Let’s say you’re sailing through the Mojave at 40 miles per hour and you hit a huge rock. Instead of receiving a nasty blow to the rear and messing up the truck’s suspension, as could happen with some weaker shocks, hydraulic bumpers absorb all of the pressure and send a smaller portion of it back through the wheel on rebound.

When we say that an off-road vehicle “absorbs bumps,” we are almost literally talking about this fact.

Ford uses similar suspension technology in the Ranger Raptor, although not as advanced. The ubiquitous Fox internal bypass shocks feature adaptive compression damping using a clever valve system that allows fluid to flow more freely through the shocks. It’s closer to the setup found in the standard ZR2.

But the Fox’s hydraulics are set for rebound (at least on the Ranger F-150, the Raptor R has new live dual-valve shocks), and the shocks still have traditional rubber bumpers. Both result in less control than the Bison during fast desert runs, at least in theory.

Robert Teseo, vehicle dynamics engineer at the Multimatic technical center, explains the basics well.

“We want something that can withstand all the aggressive off-road conditions, so it can stay in control and withstand all the stresses that come with it,” he notes. “But we also don’t want to compromise handling or comfort on the road.”

To achieve this, Multimatic had four key goals in mind when creating the DSSV shock absorbers and hydraulic bumpers for off-road use:

• Minimize body movement
• Reduce wheel travel
• Reduce the maximum load on tires and frame
• Increase energy dissipation

The first two rules are obvious once you take your truck out on the trail. The ZR2 Bison doesn’t have a lot of wheel travel like other off-road vehicles – some might describe it as “stiff” at lower speeds. But this truck was designed for high-speed off-roading, and that means it hops over rocks and dirt like a jet ski across a calm lake. It takes a really nasty hit to ruin a truck’s chassis.

This coziness extends to the road. The suspension absorbs damaged pavement as quickly as it does a rocky trail and barely shrugs over speed bumps. The only issue with ride quality (and cabin noise) are the huge tires – which is no surprise for an off-roader of this caliber.

But there’s more to the ZR2 Bison than just the suspension.

Speaking of these tires – they are just ridiculous. They are two inches larger than the already enormous 33-inch tires on the regular ZR2 and 1.2 inches thicker. Chevy actually had to move the front axle forward a step and move the offset outward by almost an inch to accommodate the new rubber. The tires increase ground clearance from 10.7 inches to 12.2 inches and increase the overall width of the truck by 2.1 inches. They also wrap around the Bison’s signature 17-inch beaded wheels.

The engine is the only area where I think the ZR2 Bison could use… more. It’s the same 2.7-liter turbocharged four-cylinder engine found in every other version of the Colorado, and here it produces 310 horsepower and 430 pound-feet of torque.

Is it too weak? Not necessarily. The four-cylinder engine has more than enough juice to get the ZR2 out of a pit at a decent speed. It shows some signs of struggle on the highway, but still grunts more than some naturally aspirated sixes in other trucks.

After a week of driving, I’d say the Chevrolet achieved its goal. Utilizing Multimatic’s clever “Jounce Control” technology and adding a host of off-road equipment unheard of in this segment, the Colorado ZR2 Bison is by far the most capable mid-size truck in the world. Just don’t tell that to the good people at Ford.

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