Lowered Car suspension (Pros and Cons)

In this brief article, we will discuss Car suspension Lowering, the pros and cons of suspension lowering and some best practices.

What is the purpose of a Low car suspension?

The basic intention behind a low car suspension is a low center of gravity. A Car’s basic road handling is influenced majorly by how high the car’s center of gravity is above the ground. It is also influenced by how low the car’s aerodynamic Center of Pressure is located. The basic objectives of a lowered car suspension are to

  • Improve handling behavior, and
  • Improve Aerodynamics

But let’s face it, a lowered car looks much more sporty as compared to a normal height vehicle. The improved visual appeal of a lowered car is undeniable.

What are the advantages of a Lowered Car suspension?

Improved handling

A Lowered suspension lowers the center of gravity (COG). A lower center of gravity means that a side force acting on the vehicle would have a smaller Moment-Arm. The moment-arm is proportional to the distance of the COG from the ground level. A lower COG means a lower probability of the vehicle getting toppled.

Improved Aerodynamics

In order to understand how aerodynamics improves, we will have to borrow a few concepts from F1 racing. Reducing the ride height increases a car’s downforce without the downside of an increase in the drag force, which tends to slow the car down.

Normal suspension setup is such that the front ride height of the car is lower than the rear ride height of the car. Maintaining this “Rake” (inclination angle of from the front to rear), if the overall car is also lowered within a certain limit, it will ensure that the undertray of the car produces downforce and not lift. Beyond this limit, any extra reduction in ride height could cause the drag to increase and also increase lift, which is not a desirable situation. 

The effect of ride height on the generation of downforce is as follows:

The basic principle is very similar to the manner by which 

wings (also called spoilers or aerofoils) can be used to generate downforce; the  only difference being that in the case of a wing it is the aerofoil geometry that has the rake angle, which ultimately results in a pressure difference between the upper and the lower surfaces of the aerofoil. This static pressure difference implies that there would be a resultant downward force acting on the car.

Reduced risk of rollover

A high COG is a disadvantage in any vehicle. A higher COG increases the risk of rollover because a higher COG increases the Moment-arm that causes rollover. 

Conversely, lowering the suspension lowers the COG by bringing the body closer to the ground and reduces the risk of a rollover.

What are the disadvantages of a Lowered car suspension?

Reduction in ride quality

Lowered springs would have lesser travel as compared to the regular springs. In order to restrict the suspension from hitting the bump stops, stiffer springs would be necessary.

Uneven tire wear

Lowered suspension would generally involve changing Camber and toe settings since the suspension arms are sitting at a different position. This wheel alignment deviation would result in increased Tire wear.

Increased underbody Scraping

With lower ground clearance, the underbody would be closer to road surfaces and mostly scrape against bumps and irregularities.

Increased bottoming out

WIth reduced suspension travel, there is lesser distance between the bump stop and the suspension bracket. This will increase the chances of the bump stop hitting.

How can a car Suspension be lowered?

Fitting a Lowering Kit an aftermarket lowering kit is the best approach. A Lowering kit would generally involve the following parts:

  • Lowering Springs: The aftermarket lowering springs would be of shorter length and be of a higher and more progressive rate in order to make the suspension work within the reduced travel.
  • Aftermarket Coilovers or shock absorbers: The new lowered stance would mean a higher spring rate with lesser travel. The original shock absorbers were tuned for comfort and more travel. The new shock absorbers would require a different damping ratio to account for the new springs. With a shorter spring, the suspension arm would be able to travel more into the bump, closer to the bump stop. This would require a shorter ‘shut height’ in the new shock absorber/Strut.
  • Modified control arms of higher strength would be required since the bump stops would be hitting more number of times.
  • Low Camber leaf spring and axle mounts: In the case of leaf springs, you would probably need a new set of springs and slimmer axle mounts.
  • UnderSlung Axle: For a leaf spring suspension, if it was an overslung axle, there might be potential to convert it to an underslung using an aftermarket kit. The axle will sit above the spring, thus bringing the chassis closer to the ground
  • Torsion Bar Key: For a Torsion bar suspension, lowering can be easily done without any additional aftermarket parts. The only thing to be done is to readjust the zero rotational position of the torsion bar.

By how much should I lower my car’s suspension?

  • Typically, for a regular sedan or hatchback, a reduction of suspension travel by an amount of 1 inch should be possible without any further issues with other components in the suspension
  • It also depends on the type of vehicle. SUVs have much longer suspension travel, hence, there might be more potential for lowering

Conclusion

In this brief article, we have discussed Car suspension Lowering, the pros and cons of suspension lowering and some best practices.

In case of any queries or comments, please feel free to ask.

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