SPL Parts Performance Rear Knuckle Bushings – GR86 / BRZ / FR-S / 86 / WRX

The SPL Parts Rear Knuckle Bushings replace the factory rubber rear knuckle bushings with low-friction, PTFE-lined spherical bearings. By eliminating rubber bushing deflection under heavy acceleration and braking loads, these bushings help reduce unwanted geometry changes, improve response, and give the driver more direct feedback from the rear tires.

Factory rubber bushings are designed with comfort and compliance in mind, but that compliance can lead to wheel hop, vague feedback, and inconsistent suspension behavior when the car is driven hard. SPL uses the largest possible FK spherical bearing mounted in a precision-machined 6061-T6 aluminum housing for improved longevity, proper fitment, and sharper rear suspension articulation.

Key Features

• Replaces Factory Rubber Bushings: Eliminates deflection from the OEM rear knuckle bushing location.
• Improves Throttle & Braking Response: Reduces unwanted geometry changes under acceleration and braking loads.
• Reduces Wheel Hop: Helps the rear suspension stay more controlled under load.
• Improves Driver Feedback: More direct rear tire feedback and sharper overall response.
• PTFE-Lined FK Bearings: Maintenance-free, US-made spherical bearings for low-friction articulation.
• Precision-Machined Housing: 6061-T6 aluminum bearing shells cut to +/- .001" tolerance for proper fitment.
• Lightweight Construction: Approximately 0.674 lbs per pair / 0.337 lbs per side.
• Sold as a Pair: Includes one pair of rear knuckle bushings for one vehicle.

Why We Like It

These are a serious suspension precision upgrade for drivers who want the rear of the car to feel more connected and predictable. By removing the soft factory bushing from the rear knuckle, the suspension can articulate more smoothly while reducing deflection under load. For track cars, autocross builds, or aggressive street setups, this helps the rear end feel sharper and more consistent.

Benefits

• Improved throttle response
• Improved braking response
• Reduced wheel hop
• Reduced unwanted geometry change from bushing deflection
• Improved rear suspension articulation
• Better rear tire feedback
• Maintenance-free spherical bearing design

Materials & Construction

• Bearing Shells: 6061-T6 aluminum
• Bearings: Steel PTFE-lined FK spherical bearings
• Housing Tolerance: Precision cut to +/- .001"
• Weight: 0.674 lbs / 306g per pair
• Weight Per Side: 0.337 lbs / 153g

NVH Notes

The SPL rear knuckle bushings are a moderate contributor to added noise, vibration, and harshness. Because this bushing location helps absorb vibration from potholes, rough pavement, and road irregularities, replacing the OEM rubber bushing with a spherical bearing reduces longitudinal suspension compliance.

When combined with spherical traction arms, these bushings may add a similar level of NVH as the traction arms. When combined with solid subframe bushings, longitudinal bushing deflection is largely eliminated, which can result in a noticeable increase in NVH over rough roads. Larger tires with taller sidewalls, lower tire pressures, and high-quality shocks can help improve comfort.

Confirmed Fitment

• 2022–2026 Toyota GR86
• 2013–2021 Toyota 86 / GT86
• 2013–2016 Scion FR-S
• 2013–2026 Subaru BRZ
• 2015–2021 Subaru WRX / WRX STI, including Type RA
• 2022–2026 Subaru WRX

Replaces OEM Part Numbers

• Toyota SU003-00366
• Subaru 20254-CA000

Specifications

• Brand: SPL Parts
• Product: Rear Knuckle Bushings
• Position: Rear knuckle
• Bushing Type: PTFE-lined spherical bearing
• Quantity: Pair, one pair per vehicle
• Application: GR86, BRZ, FR-S, 86, WRX, and WRX STI

Installation Notes

• Professional installation is recommended.
• Factory rubber bushings must be removed and replaced with the SPL spherical bearing assemblies.
• Specialty bushing removal/installation tools or a press may be required.
• A full alignment is recommended after installation.
• Refer to SPL’s GR86 / BRZ / GT86 / FT86 / WRX rear knuckle bushing installation instructions before installation.

What’s in the Box

• (1) Pair of SPL Parts Rear Knuckle Bushings
• Included SPL components per kit contents

Compatibility & Disclaimers

Designed for compatible Toyota GR86, Toyota 86, Scion FR-S, Subaru BRZ, Subaru WRX, and Subaru WRX STI applications. Sold as one pair per vehicle. These bushings may increase NVH compared to factory rubber bushings. Suspension feel, wheel hop reduction, and handling results may vary depending on tire setup, alignment, ride height, traction arms, subframe bushings, shocks, and intended vehicle use. OEM part number references are provided for general compatibility guidance only, as manufacturers may revise part numbers over time.