This is a purely theoretical class. I will tell you about understeer and oversteer, two terms that we often talk about.
Whether you are looking at our driving and test reports or chatting with friends about the car, you will always read or hear or say two terms-understeer and oversteer. From the literal it is not difficult to see that these two terms are related to the vehicle turning. Yes, it is not only related, but also very close. Understanding these two things will help us drive a lot.
The first is safety. We know that severe understeer or oversteer will eventually cause the vehicle to lose control, so knowing their causes and correct handling methods can help us prevent and avoid accidents. Secondly, in the next few lessons, we will talk about some advanced driving techniques. These theoretical knowledge are the basis for the latter.Okay, let’s start the class officially, be serious
Understeer and oversteer
1. What is understeer and oversteer
Understeering translated into English is understeering, commonly known as push head. It shows that the actual steering angle of the vehicle in a bend is smaller than the rotation angle of the front wheels, that is, the front wheels slip to the outside. Oversteering is translated into English as oversteering, commonly known as flicking. It appears that the actual steering angle of the vehicle in a bend is greater than the rotation angle of the front wheels, that is, the rear wheels slip to the outside.
2. Causes of understeer and oversteer
There are many factors that cause understeer or oversteer. This Kamm diagram can help us understand it well. The X coordinate represents the centrifugal force generated by the inertia of the vehicle attached to the wheel when turning (mainly affected by the speed and steering angle), the Y coordinate represents the driving force attached to the wheel, the Z coordinate represents the resultant force
This is a purely theoretical class. I will tell you about understeer and oversteer, two terms that we often talk about.
Whether you are looking at our driving and test reports or chatting with friends about the car, you will always read or hear or say two terms-understeer and oversteer. From the literal it is not difficult to see that these two terms are related to the vehicle turning. Yes, it is not only related, but also very close. Understanding these two things will help us drive a lot.
The first is safety. We know that severe understeer or oversteer will eventually cause the vehicle to lose control, so knowing their causes and correct handling methods can help us prevent and avoid accidents. Secondly, in the next few lessons, we will talk about some advanced driving techniques. These theoretical knowledge are the basis for the latter.Okay, let’s start the class officially, be serious
Understeer and oversteer
1. What is understeer and oversteer
Understeering translated into English is understeering, commonly known as push head. It shows that the actual steering angle of the vehicle in a bend is smaller than the rotation angle of the front wheels, that is, the front wheels slip to the outside. Oversteering is translated into English as oversteering, commonly known as flicking. It appears that the actual steering angle of the vehicle in a bend is greater than the rotation angle of the front wheels, that is, the rear wheels slip to the outside.
2. Causes of understeer and oversteer
There are many factors that cause understeer or oversteer. This Kamm diagram can help us understand it well. The X coordinate represents the centrifugal force generated by the inertia of the vehicle attached to the wheel when turning (mainly affected by the speed and steering angle), the Y coordinate represents the driving force attached to the wheel, the Z coordinate represents the resultant force, and the circle representstireMaximum adhesion to the ground.
tireThe adhesion force produced under certain conditions with the road surface is a constant value, and changes in the centrifugal force and driving force will cause the resultant force to change. When the resultant force is greater than the adhesion force, the tire will slide in the direction of the resultant force. If this tire is on the front wheel, then understeer is present. If this tire is on the rear wheel, then oversteer is present.
3. Is the front-wheel drive necessarily understeer, and the rear-wheel drive must oversteer?
A common saying we can hear is that front-wheel drive vehicles are characterized by understeer and rear-wheel drive vehicles are characterized by oversteer. This statement is not entirely correct, it is a more one-sided statement, it describes the situation of tire slip caused by the change of driving force. The driving force of a front-wheel drive vehicle is applied to the front wheels, and a sudden increase in driving force will naturally cause understeer. The driving force of a rear-wheel drive vehicle is applied to the rear wheels, and a sudden increase in driving force will naturally cause oversteer. This is an artificial understeer or oversteer.
There are many factors that we can change artificially, such as increasing centrifugal force or reducing adhesion. If you enter a corner at a very fast speed, understeer will occur in both front-drive and rear-drive vehicles.Suppose vigorouslybrakeAt the same time, if you slam the direction, both front-drive and rear-drive vehicles will oversteer. In fact, for mass-produced civilian cars, regardless of the front and rear wheels, the steering characteristics of the vehicle itself are neutral or slightly imperceptible understeer. This is achieved by the geometric angle of the suspension (too esoteric and beyond the scope of this article).
What about four-wheel drive? Since four wheels share the overall driving force of a four-wheel drive vehicle, the driving force allocated to each drive wheel is smaller than that of a front-wheel drive or a rear-wheel drive vehicle, so the four-wheel drive vehicle can withstand a greater overall drive force. This is why four-wheel drive vehicles generally have higher cornering capabilities than front and rear drive vehicles. (Dahe Net)
