Propickup Digital Magazine
Issue link: https://read.dmtmag.com/i/173151
Controlling your truck's weight transfer is the key to maintaining traction and steering By Mark Cox A n overnight dusting of snow crunched under the tires as the driver of the 4x4 crew cab pickup rolled slowly through the suburban Idaho neighborhood and made a turn towards the main highway a few blocks down the hill. The light at the "T"-intersection flipped to red a half-block before the highway and the driver instinctively slipped his foot to the brake pedal and started braking. A second later his brain realized there was a big problem: We aren't stopping before the intersection. A combination of too much speed and too little traction caused the ABS system to chatter away as the tires kept rolling. A few seconds later the truck slid half sideways into the busy intersection as momentum and gravity did their thing. Welcome to the realities of winter driving. There's no doubt any contractor or business owner who lives or works in the Snow Belt has had the unpleasant experience of losing vehicle control in the winter. For some it may have been only a momentary happening and the skip of a few heartbeats. For others, well, there was probably a lot of company paperwork to fill out and an insurance claim to file. WEIGHT TRANSFER Most of us know the more slippery the road, the higher the speed, the heavier the vehicle, or a combination of all three means the longer it takes for steering, acceleration and braking inputs to affect the vehicle. Driving on slippery surfaces requires you to make vehicle control inputs far earlier and much slower and smoother than you would driving on dry pavement. It's all related to controlling vehicle weight transfer. BASIC DRIVING TIPS As you drive down a level road at a constant speed, your truck's weight is "neutral," or balanced evenly front to back. However, as soon as you begin to decelerate, that weight balance shifts forward. This puts more weight on the front tires, giving them more grip, helping both braking and steering. At the same time the rear tires have less weight on them and, consequently, less traction. Conversely, if you accelerate, more weight shifts to the rear tires, which gives them more grip – and the front tires less grip. These driving inputs and weight shifts go unnoticed in good driving conditions. But on snow and ice they are magnified a hundredfold because the tires are already at their limit of grip before any weight transfer begins. In simple terms, when negotiating a turn on a low-grip surface like a snow-packed road, always slow down slowly in a straight line so you are utilizing your truck's available grip at all four corners for deceleration. Then begin to steer into the turn after you have finished decelerating and your foot is off the brake. Doing so allows the vehicle's weight transfer to provide braking to the front tires, and you gain steering effectiveness through the corner because you are using 100% of the grip to steer. As you exit the turn and the front tires are once again pointed straight ahead, slowly accelerate, using the weight transfer to the rear tires for added grip. Remember: Brake. Steer. Accelerate. But never overlap those driving inputs. FOUR WHEEL DRIVE ADVANTAGE At this point, someone always makes the comment, "But my truck has four-wheel drive, so it's okay to drive faster." Sorry to burst the 4x4 bubble: Four-wheel drive can never over- come the simple laws of physics and weight transfer. -wheel drive does allow a slightly larger margin for weighttransfer error during acceleration, but it cannot magically create better braking or steering. That's where so many 4x4 owners make their biggest driving mistakes. In fact, 4x4 trucks are more difficult to brake and steer than cars because they are heavier and usually run wider tires, which typically creates less traction on snow/ice. More truck, more mass, more weight transfer mass, more difficult to control. SMOOTHNESS IS KEY The best winter drivers are the ones who are smooth. The best winter drivers are the ones who are aware of what's happening around and way in front of them. PROPICKUP DIGITAL PP1013_Snow Driving Tips.indd 38 9/9/13 2:00 PM