Test drive: truck with a twist: four-wheel steering for tight turns

Tools of the Trade, Nov-Dec, 2002 by Michael Morris Killanin, Lord

Today's pickup tracks are a far cry from the basic beaters I drove when I started out in construction 30 years ago. But great new features like all-wheel drive, super cargo capacity, and extended cabs have added size along with performance. Hitch a job trailer to the back of one of these high-wheeled, crew-cab monsters and handling gets real interesting, real quick.

So after spending a week driving a new GMC Sierra Quadrasteer pickup (with trailer in tow) on highways, winding country roads, and ridiculously narrow lanes through old New England villages, I have become a true believer in the power of 4-wheel steering.

That's right--all four wheels on this mechanical marvel turn in unison, making tight circles possible and towing a pleasure.

Unlike most power-steering systems, which use hydraulics to turn a vehicle's front wheels, the Quadrasteer also employs wheel-position sensors, microprocessor technology, and a small electric motor to turn the rear wheels up to 12 degrees. Even more amazing, these wheels turn the opposite way (from the front wheels) at slow maneuvering speeds, then automatically switch around and turn the same way at higher driving speeds.

The result is incredible maneuver-ability when you're inching this big, brawny beauty of a truck around a tight corner or squeezing it into a parking space. At highway speeds, it helps prevent the vehicle from leaning or "yawing" in turns, which can be a big plus when you've got a heavy load in the bed.

Three steering modes are available through a simple push-button setup on the dashboard: "2WS" for front-steering only; "4WS" for all-wheel steering; and "4WS Tow," which imperceptibly decreases the amount of rear-wheel turn at low speeds and increases it at high speeds for trailering stability. At its most effective in 4WS, the system reduces the truck's turning diameter by a significant 21 percent, from 46 feet to 37 feet. How tight is that? About the same as a very compact Saturn coupe, according to GM.

Quadrasteer is available only on GMC Sierra and Chevy Silverado pickups and full-size Yukon SUVs and adds around $5,000 to the cost of the vehicle.--Michael Morris is a freelance writer and contributing editor to HANLEY-WOOD'S TOOLS OF THE TRADE.