How to Decide On Your Very First Race Car (Part 4)
Now that front and rear wheel drives have been discussed, it is time to take a look at more sophisticated forms of drive design. Four wheel and all wheel drive are the best drives for off-roading, autocross, and rally. They provide superior traction and
excellent control in dirt, water, pavement, or wherever else auto racing can take you.
But before discussing all wheel and four wheel drives, one must understand the concept behind normal driving, which everyone takes for granted. One of the most important parts of the drivetrain, and arguably the entire car, is the differential.
There are different types of differentials, but first we will take a look at how they work.
Those who are familiar with racing will know what an inside line is. For those who have taken refuge at the bottom of a lake or somewhere similar, to shy away from mainstream racing, an inside line is basically the fastest route around a track. Now, the
principle of the inside line is why each and every vehicle produced has a differential. Whenever you turn your car, the wheel on the inside of the turn rotates less than the wheel that is on the outside.
Still confused?
For example, you are making a right hand turn at an intersection. The right wheel, which is the inside wheel, will rotate about 10 times, while the left wheel, or the outside wheel, will rotate 12 times. This results in different rotation speeds of the wheels.
This is where the differential comes in. it allows the wheels to move at different speeds. But this is not always good, and those who have been stuck in mud or snow with one tire spinning, and the other one resting uselessly, can relate.
Although a differential is useful when it comes to turns, it does no good in distributing power.
Then nature of a differential is to split drive power. If one wheel starts to lose traction, the differential will transfer more power to it. Now this can be useful on turns, but when you are stuck, this does no good. The wheel that is stuck will keep spinning
with no traction, while the wheel that has traction does not spin.
To deal with this, engineers have introduced a different type of differential, known as a limited slip differential or LSD. Like the name implies, this device limits slipping by distributing even power to both wheels when needed. It is generally an optional
or aftermarket feature, and allows the wheels to spin as though they are on a single axle, while still allowing them to rotate at different speeds on a turn.
Now a limited slip differential or normal differential is used in every vehicle being produced today. They allow longer tire life, easy maneuvering, and help in instances where you car is stuck. That is why it is called a LSD. It allows slippage, but only
on turns.
Now onto something that is a bit more complicated. Yes, even more complicated than a differential. Four wheel drive and all wheel drive. First we will take a look at four wheel drive.
If you are driving through snow or mud, a four wheel drive will still be problematic. Why? Because there is a differential on the front and rear axle, meaning that if you are stuck, one front and one rear tire will spin. Of course, this is better than two
wheel drive, since you have drive power that is both pushing and pulling the car.
When a four wheel drive system adds a LSD or locking differential, then it actually lives up to the name, “four wheel drive.” This allows the car to power all four of its wheels when required.
But wait, isn’t all wheel drive the same thing as four wheel drive?
Not at all.
To find out why, check out the next article.
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