Controlling Your Balance on the Road: Pitch, Roll and YawUpdated Sept. 25, 2020
The balance of your vehicle (where its weight sits) will be altered every time you speed up, slow down or turn the steering wheel. We introduced the idea of vehicle balance – and why it is so important – in the previous module of this section. Go catch up now if you have yet to read through it.
Here is a quick recap of how the weight of your vehicle shifts when you perform basic maneuvers:
Acceleration moves the center of gravity toward the back of the vehicle, taking weight out of the front tires.
Deceleration moves the center of gravity toward the front of the vehicle, taking weight out of the rear tires.
Steering towards the left or right moves the vehicle’s center of gravity in the opposite direction, taking weight out of the left or right tires respectively.
You must learn how different maneuvers affect the distribution of weight across your vehicle’s four tires, to keep your balance on the road. Abrupt speed or direction changes can result in weight shifts sudden enough to throw the vehicle into a skid or cause it to turn over. The most catastrophic off-road crashes, accidents and collisions are often caused by a combination of high-speed driving and poor balance control. Any time weight is shifted away from one side of the car, there is the potential for complete loss of traction and skidding to occur, or for the wheels on that side to completely lose contact with the roadway.
- If you brake and steer right suddenly, the abrupt balance shift towards the front, left of the vehicle could cause your rear wheels to spin out toward the left.
- If you make the same maneuver but strong traction in your left, rear wheel resists the force of the skid, your right wheels may lift away from the road and the vehicle will roll over toward the left.
Fortunately, precise steering, smooth acceleration and gradual braking can prevent loss of balance. Of course, you must also keep your vehicle in good working order and stick well within a safe speed for current roadway conditions.
When the weight of your car moves toward the front or the back, this is known as pitch. Forward pitch occurs whenever you apply the brakes, shifting the balance away from the back of the vehicle and into the front wheels. If you brake suddenly, you will notice the hood of the vehicle dipping towards the road and feel the rear of the vehicle lifting slightly. Extremely abrupt braking can result in severe rear-wheel traction loss and complete loss of directional control. Note that shifting directly from acceleration to braking (as you might if a hazard suddenly appeared in the roadway) will exaggerate the effects of the rear-to-front weight transfer.
If you are traveling along a straight stretch of road, applying the brakes gradually will keep the weight of the vehicle distributed more evenly between the four wheels, maximizing rear-wheel traction and reducing the likelihood that you will lose control.
Avoid braking when driving through a curve or bend in the road, as forward pitch could result in oversteer. As the vehicle’s weight shifts forwards, your rear wheels may lose connection with the road surface and swing out to the side as you turn. Always reduce your speed gradually, before entering a curve in the road.
Backward pitch describes the shift of weight from the front into the back wheels of the vehicle. This will occur whenever you accelerate. Rapid acceleration results in a sudden backwards pitch, causing the rear of the vehicle to dip and the hood to lift. Backward pitch cannot be avoided and will always occur to some extent when you accelerate. However, you can maintain better balance by applying gradual pressure to the accelerator, whenever you wish to pull off or increase your speed.
Avoid sudden acceleration as you approach a corner or bend in the road, as it could result in understeer. When the abrupt backward pitch reduces traction in the front tires, your attempts to steer around the curve of the road may be ineffective, causing you to drive straight off the side of the road.
Roll is the term used to describe the sideways shift of weight in a vehicle from left to right, or vice versa. Your vehicle’s balance will shift from one side to the other whenever you steer. How suddenly this shift occurs will depend on how sharply you steer and how fast you are traveling. Roll always acts in opposition to steering:
- When you steer right, the vehicle will roll left.
- When you steer left, the vehicle will roll right.
Understanding this side-to-side weight transfer can help you to become a safer and more skilled driver. Taking a corner or a bend in the road with a sudden movement of the steering wheel can lead to an abrupt sideways shift that rolls your car over, if the rear wheels still have decent traction. This is even more of a danger in high-sided vehicles like SUVs and pick-up trucks which are more susceptible to rolling. However, if you steer around a corner or a bend smoothly and progressively, the gradual shift of weight toward the outside wheels can improve your grip on the road’s surface and allow you to take the corner at a higher speed, while still maintaining control.
Yaw describes a change in vehicle balance which causes the car to spin around its center of gravity (imagine this as a vertical pole through the middle of your vehicle). Like roll, yaw is the product of a sudden side-to-side weight shift caused by sharp steering. Yaw is more likely to occur on slippery surfaces when both rear tires have poor traction, causing the back end of the vehicle to spin away from the direction of the turn rather than lifting off the ground sideways.
Vehicle balance control techniques
Many maneuvers cause multi-directional weight shifts (I.e. braking while turning right shifts the balance of the car forwards and to the left, while accelerating and turning left would result in a shift backwards and to the right). Understanding these effects will help you get the best performance from your vehicle while driving, as you can use them to your advantage.
Imagine you’re approaching a curve in the road and need to reduce your speed. If you enter the curve at speed and apply your brakes as you drive through it, the forward pitch and sideways roll may result in serious traction loss and a skid mid-curve. A savvy driver who understood vehicle balance would brake almost to the point of wheel lock BEFORE entering the curve, then take their foot off the brake pedal as they drive through it. The forward pitch before the curve will improve traction as they begin the turn.
Vehicle balance and tire condition
Even the most skilled driver in the country may not be able to prevent a skid in a vehicle with damaged or worn-out tires. The condition of your tire tread has a dramatic effect on traction and the results of shifts in vehicle balance. Any sudden shift in weight is much more likely to lead to loss of control if your tires are old, unevenly inflated or not inflated to the manufacturers recommended pressure. Keep your tires in good shape – it is essential to your safety!
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