Moving on slippery roads is always an obsession for many people because they are prone to unintended incidents.
This is why your car needs a traction balancer for situations like this. Among them, limited slip vs posi are the most popular options.
So what’s the difference between them? We will reveal it in the next sections!
What Is Posi traction And Limited Slip?
Limited Slip
The limited slip differential (LSD) is the round chuck located in the center of the rear axle of the engine.
It is responsible for adjusting the speed of each wheel as they slide to help the vehicle move more smoothly.
The wheels have the same speed when the car moves in normal conditions, so it does not affect the balance and stability.
However, when the vehicle turns a corner, each wheel will have its speed to ensure traction.
The wheel outside the corner will have a faster speed than the other wheels, so without LSD, the wheels will lock together, leading to extremely dangerous slippage.
The limited slip structure consists of worm gear on the shaft connecting the two wheels.
When the wheel rotates, it receives torque from the drive shaft and distributes it to each wheel, creating braking force at the semi-axle.
This helps to distribute the right transmission force to the driving wheels, between balance and stable operation for the vehicle.
LSD increases traction, reducing drag and making it easier for your vehicle to overcome bad terrain without increasing operating power.
Posi
Posi, positraction, or posi rear end are all words used to refer to the exclusive limited-slip differential model of the General Motors brand.
First introduced in 1957 on the Chevrolet model, the posi unit quickly impressed the car market with familiar and strange features.
The first car models had only connected the two wheels by fixed axle shafts; it could not create a difference in speed between the wheels.
Car manufacturers continuously released their type of differential versions until the 50s and 60s of the last century.
The introduction of this standard differential type was a breakthrough move for General Motors then.
It divides the engine’s torque into two lines, or in other words; it allows the two sides of the wheel to rotate at two different speeds.
When cornering, the distance that the front and rear tires can travel will also be different. The fact that the wheels rotate at different speeds helps to create balance and stability.
The drive gear at the end of the moving shaft rotates the gear ring, transmitting power to the differential housing gear assembly.
By combining loads, this type of differential helps each wheel spin at its speed.
What Are The Differences Between Limited Slip Vs Posi?
Posi traction vs limited slip are the type of differential versions that are responsible for regulating the rotational speed of a car.
After all, there are still certain differences between these two types of details in terms of design and production structure and working methods.
The first is about design. Since the true differential is a detail that Chevrolet models specifically designed for its models, it has a slightly different construction than the type of differential variants.
Depending on the version, it can be spiral, mechanical, or any other design.
As for how it works, posi rear senses and analyzes which wheel has more traction when a tire is stuck or skidded. It will transmit power to this wheel.
Next, it will transfer power to the other until both tires have equal control. This is ideal for drivers who often travel on muddy or slippery routes.
The limited slip, on the other hand, stabilizes the speed between the wheels by limiting the amount of power the traction wheel receives compared to the revolution that slips.
This helps a lot when cornering, as it prevents tires with poor traction.
What Are Pros & Cons of Limited Slip Differentials?
Although it plays a big role in ensuring the smooth and safe operation of the car, the limited slip still has certain limitations, like many other engine devices.
Understanding the pros and cons below will help you have more basis when choosing.
Pros
Control And Cornering
When you spin a ball around a rope, you will find that it moves much faster and covers more ground than the string in your hand.
This phenomenon is similar to when we steer a car into a corner.
The velocities of the inner wheels tend to rotate more slowly and move less than the outer ones.
You will now need this type of differential to drop in speed difference, which adjusts the amount of power sent to all the wheels to align and stay in sync.
This is a big plus because, without it, the speed difference increases and makes it difficult for the car to corner.
In some cases, the vehicle can also overturn if the driver makes a sharp and quick turn.
Energy Efficiency
Limited slip is the ideal equipment manufacturers of high-performance cars often choose.
This part contributes significantly to the vehicle’s deceleration when a sports car is cornering at high speed.
The power reduction can be of great value when the driver tries to get the most out of the car in races.
The traction that the true differential housing produces is higher, so it will help significantly increase the car’s speed and performance.
Safer
Improvement of traction of limited slip gives the driver better vehicle control.
When traveling on rough or slippery roads, slippage and rotation of the tires are inevitable, especially when cornering.
The part will help limit this significantly to limit the possible risks.
Less Abrasive
This unit helps balance the traction from the spare wheels and transfer it to the other ones gripping the road.
It is like a friction modifier on road conditions, preventing uneven tire wear. Without it, the tires would spin and wear out very quickly.
The limited slip also helps relieve pressure and strain on the shafts during rotation because it can rotate at various speeds.
Differential motion reduces wear better compared to cars with normal motion.
Reasonable Price
The good news for drivers is that upgrading a vehicle with this part does not require too much extra cost.
Depending on the repair center, the price will vary a bit, but on average, it will range from 600 – 1200 dollars for original equipment.
Compared to the safety benefits that it brings, this is a number that does not require much thought.
Cons
Unable To Transmit Full Power
When a certain wheel has traction, this unit cannot provide full force to it. It will still have to divide a small amount of energy among those without traction.
It cannot provide 100% power to one wheel.
Difficult To Manage Traction
It’s not always possible for drivers to predict how traction will act when riding on rough terrain, sand, and mud.
Although this part transmits some of the power to the wheels that have lost traction, it cannot supply it continuously.
When the other tires lose traction, the differential housing transfers more power and can pull the car sideways.
Not All Are The Same
Depending on each version, the design of the LSD is not fixed in a certain form.
Besides the fixed-value type, there are many other variations of torque-sensitive, electronically controlled, and speed-sensitive. They can control the vehicle in different ways.
So when you want to install or replace, choose the right type that your car needs and original equipment.
What Are Positives And Negatives Of Posi Rear End?
The advantages and disadvantages of positraction vs limited slip have many similarities because they perform the same functions.
If your car doesn’t have a posi, another traction control unit must redirect the force.
This type of differential is of great help to drivers, especially when very unfortunate situations occur on the road. It helps to increase vehicle control on any complex terrain.
Another plus is that it burns less when the rotation of the tires is uneven. It also supports wheel locking and helps improve the cycle.
However, the variable amount of torque is easy to wear out the tire, and the repair cost is also quite expensive. This original equipment is quite pricey but is a much-needed addition.
Is Limited Slip Good for Racing?
Both racing and commercial vehicles possess a modern design but go in two different directions. Racing engines focus mainly on how to optimize in terms of speed and power.
With this customer group, the comfort and interior of the car do not need to be too sophisticated and luxurious.
They care about whether the performance cars are strong enough to provide the driver with a sense of excitement when cornering at high speed.
That’s why the design of drag racing cars will be a little different from the popular models. However, a limited-slip diff is still a must-have for races.
This part allows racers to get the best out of even on bad roads like ramp style to ensure safety and outrun rivals.
Regardless of the terrain and complexity of the landscape, it can even help you improve your performance and save time on the finish line – the most important thing in competitions.
Applying a limited slip on the car also plays an important role when a certain wheel suddenly fails and loses traction.
This lack of traction compensation allows riders to cross wet or rough roads easily.
Conclusion
The two types of differentials we analyzed above slightly differ in structure and expression. The pros and cons of limited slip vs posi are also quite similar.
The choice depends on the purpose of use and the type of vehicle.