Truck Traction & Brakes Tech

Knobbies, lifted suspension, winches, tow straps, and locking differentials are familiar tools of the off-road trade, but they're being significantly supplemented--and in some cases replaced--by a new generation of computer-controlled technology that can give highway-friendly trucks and SUVs serious trail capability.

Nowadays, computers can apply the brakes to restrain spinning wheels, directing power to the wheel that has grip. Until recently, such technology was only found on high-end luxury SUVs, but now affordable pickups like the Nissan Frontier and Toyota Tacoma offer traction-control systems. Myriad other tricks also are increasingly available on mainstream trucks and SUVs, including hill-descent control, hillstart control, remapped electronic throttle sensitivity, and electronically lockable differentials.

Nissan's solution to more traction is to include an electronically activated rear locking differential, only lockable when the vehicle is in low range. In addition, to prevent the Vehicle Dynamic Control system from cutting engine power during high or low-speed wheel slip, Nissan has also installed a "VDC Off" switch.

Purists may scoff at such electronic trickery as gadgets that don't measure up to the traditional hardware, but the electronic devices not only cost less than their mechanical counterparts, but often work better and add capability that's simply not possible with mechanical traction devices.

"I can only see the value of some of these things when I've been able to experience them off-road," concedes Paul Williamsen, an avid off-roader and curriculum development manager for the University of Toyota.

While enthusiasts like to rely on their own skill in sticky situations, "there are two things these systems can do that a driver can't," Williamsen adds. "They can act much more quickly, and, something that even the best driver can't do, these systems can act differently on all four wheels. Even the best among us can't do differential braking of the left-front and right-rear."