HKS TYPE-S Rear Under Spoiler - 2022+ Subaru BRZ / Toyota GR86

TYPE-S Rear Under Spoiler for the 2022+ Subaru BRZ and Toyota GR86

The HKS TYPE-S Rear Under Spoiler for the 2022+ Subaru BRZ and Toyota GR86 extends the rear bumper's lower edge to manage the airflow exiting from under the car. The rear underbody is where most of the aerodynamic work happens at speed. Airflow exiting the underbody at the rear creates a low-pressure zone that can either work for the car's stability or against it depending on how it is managed. The TYPE-S rear under spoiler directs that exit flow to reduce rear lift and improve rear-axle downforce.

Specs & Highlights

• Rear under spoiler / diffuser extension
• Manages underbody exit airflow
• Reduces rear lift at speed
• Part of the TYPE-S aero family for the 2022+ GR86/BRZ
• Polypropylene construction
• Fitment: 2022+ Subaru BRZ / Toyota GR86

40mm Extension, 5-8 kg Downforce, 15 kg Lift Reduction

The rear under spoiler extends the lower rear bumper lip by approximately 40mm downward and 25mm rearward, directing underbody exit flow at a more favorable angle relative to the road surface. HKS's published contribution for this piece in isolation is approximately 5–8 kg of rear downforce at 200 km/h. Its more significant contribution is reducing rear lift, the factory rear undertray exits flow in a way that creates negative downforce (lift) at speed, and the under spoiler reduces this lift by approximately 15 kg at 200 km/h.

Rear Underbody Exit Flow Management

The rear under spoiler is most effective when paired with the front TYPE-S pieces. Front aero and rear aero work together to manage the pressure balance under the car from entry to exit. Running only rear aero can shift the aerodynamic balance toward understeer at speed; running front and rear together is how HKS tuned the TYPE-S system.

Best Effect When Paired with Front TYPE-S Aero

Ships unpainted for body-color or contrast finish application. Polypropylene construction for flexibility and impact resistance. All mounting hardware included. Installation uses the factory rear bumper mounting architecture.

The FT Breakdown

The rear under spoiler is one of the less visually dramatic pieces in the TYPE-S family but one of the more aerodynamically significant. It does most of its work out of direct sight, managing underbody flow exit at the rear. For GR86 and BRZ owners building toward the complete TYPE-S aero setup, this piece closes out the rear of the car. The 15 kg lift reduction is arguably more important than the 5–8 kg downforce addition for street driving. Reducing lift at the rear makes the car feel more planted and stable at speed in a way that the driver notices as improved confidence rather than identifiable downforce. The 40mm extension is a small physical change that produces a disproportionate aerodynamic benefit at the rear.