Time and time again, we see modified vehicles plying the road, many of which feature massive rear wings that almost make the car look like a DTM refugee. Being large enough to hold an impromptu picnic, we’ve often wondered if those appendages are actually road legal.

So first things first – what is a rear wing? Simply put, it’s an aerodynamic device with aerofoils that deflect the air flowing over them, making it go upwards. This creates downforce, which pushes the rear end of the car down to the ground, increasing grip and enabling you to corner faster.

But that’s on the track; the reality is that on a public road you’re much more likely to be stuck in traffic crawling at 20 km/h than blasting through a series of corners at 200 km/h. So, with no real use for it in everyday driving, are you actually allowed to put a rear wing on your car?

Turns out, the answer is yes, according to Datuk IR. HJ. Mohamad Dalib, director of the automotive engineering department at the Road Transport Department (JPJ). “However, the wing is not allowed to significantly exceed the size of the body of the vehicle in question,” he said.

In fact, the spoiler can be three inches wider on either side of the car and sit as much as six inches above the roofline. Mohamad Dalib explained that JPJ allows the use of a rear wing because it improves a car’s aerodynamic performance and helps the driver retain control of the vehicle.

“A rear wing creates downforce that enables the driver to have better control in the corners, as well as improving the braking performance. It is not just for cosmetic purposes,” he said. However, Mohamad Dalib advised drivers to use a rear wing that has been designed and installed correctly, in order for it to have the desired effect.

“The problem is, from my own observations, there are plenty of drivers in Malaysia who use a rear wing solely to enhance their car’s aesthetics,” he said. “There are also many others that have wings that are wrongly designed or installed; as such, they become only trays that do not work as intended, and in fact they could actually be affecting the performance of the vehicle.”

In conclusion, a rear wing is absolutely road legal, as long as their dimensions fall within the specified regulations. Now, for a modification that is not road legal, read our report on why JPJ is clamping down on the “hellaflush” trend and headlight conversions.