Sunday, 27 January 2013

Steering, it has types you know!

I am talking about various types of Steer-Defects we have when it comes to cars! Over-Steer, Under-Steer and Torque-Steer. The following post is to discuss the three, so you can know everything about them.


Green line is the Expected path, Red line is the path due to Over-Steer

When you turn the steering wheel, you know the path that the Car should follow, because that is why you turned the wheel. But sometimes, the car steers more than the expected turn. This condition is called Over-Steer, or in terms we know it better, Corner-Drifting. If you have seen Fast and Furious Tokyo Drift, this  is the main reason for those cool Skids performed. Now this condition is usually found in Rear-Wheel Drive cars, but Front-Wheel Drive cars are not unaware of this. If you think your car cant Over-Steer, spend about 40000-50000 on your car to get Lower Ride Height, Lower Profile Tires, some spoiler on the rear (Particular for Rear-Wheel Drive cars, to grip the Rear wheels more) and a Roll-Cage, if you will, for Safety.

Now as cool as it may look, but Over-Steer is not legal, and very Dangerous if performed on a car which is not modified properly or not capable of performing it, which is the case of Cars with greater heights, and tires with good amount of grip.

Front-Wheel Drive cars, which are very common in India, can also perform Over-Steer, but that is very difficult. The easiest way is by getting to a good speed, turning the steering wheel slightly, and then pushing the Handbrake with its release button pressed. The Handbrake should be released after about 2-3 seconds, or the car may flip.


Green line is the Expected path, Red line is the path due to Under-Steer

When the expected turning path is more than the path we actually achieve, then the car is said to Under-Steer. This is very common in Front-Wheel Drive cars because the front wheels have the work of driving the car as well as steering it. This is also common during a rainy day, as the car cannot grip well on the wet surface. This is very dangerous, and is the major contributing factor in majority of accidents where the car is speeding and is about to turn.

Under-Steer is considered a very bad thing in a car, because its very dangerous, and a lot of power of the car is wasted during this event.


*the above video demonstrates Torque-Steer in a MazdaSpeed3

This is a phenomenon seen in a variety of cars in India. This is the event of pulling of the car to one side during acceleration of the car. This effect can be very easily spotted. All you have to do is take your car on a straight road, leave the steering wheel and accelerate from Zero. You will notice the car tends to go to one direction, and not in the straight path. This is also spotted if you suddenly accelerate a car which is already in motion. This is very common in Front-Wheel Drive cars. Another reason for your car going into one particular direction could be because the alignment of the car is not correct, which can be easily undone by a local mechanic.

Main bad-effects of Torque-Steer is that one wheel in the front wears out quickly. This can be avoided by rotating the wheels at every 5000 Kms.

One major cause of Torque-Steer is unequal lengths of the Front Axels. This means that the Power which is delivered to either wheel is unequal, but by a very small amount. Use of Limited-Slip Differential is the solution to this, or the use of an intermediate shaft to make the lengths equal (A technique employed in almost all modern cars)

I hope this post helped increase your knowledge. 

thanks to wikipedia for the pics, and youtube for the video!

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