SPL Rear Knuckle Bushing (2015+ WRX, 15-21 STI, 2013+ BRZ)

The SPL rear knuckle bushings replace the rubber factory knuckle bushing with a low friction PTFE-lined spherical bearing. Replacing the OEM rubber bushing eliminates deflection under heavy acceleration and braking loads that leads to unwanted geometry changes, and prevents binding by allowing the knuckle to smoothly articulate. The reduced deflection also translates to improved driver feedback from the tire and better overall response. We use the largest possible FK bearing, to increase longevity and reduce NVH, mounted in a 6061-T6 aluminum housing precision cut with +/- .001" tolerance to insure proper fitment.

Benefits

• Lightweight: 0.674 lbs (306g) / 0.337 lbs (153g) per Side
• Improves Throttle and Braking Response
• Reduced Wheel Hop
• Maintenance-Free, US Made, PTFE-Lined FK Bearings

Materials

• 6061-T6 Aluminum Bearing Shells
• Steel PTFE-lined FK Spherical Bearings

The SPL rear knuckle bushings are a moderate contributor to NVH. The rear traction arm knuckle bushings are an active part of reducing the felt vibration from potholes, rough pavement, and other road irregularities. By replacing one of the OEM rubber bushings with a spherical the longitudinal compliance of the suspension is reduced.

If combining the rear knuckle bushings with a spherical traction arm as well, then the rear knuckle bushings will add a similar amount of NVH as the traction arm. When combined with the solid subframe bushings it eliminates all longitudinal bushing deflection and will result in a noticeable amount of NVH over rough roads. Running larger tires with taller sidewalls at lower pressures and high-quality shocks will improve the NVH.

Replaces OEM Part Numbers

This is a list of known OEM part numbers. OEMs constantly make changes to part numbers due to part updates, suppliers, etc so this may not be a complete list.

Toyota
SU003-00366

Subaru
20254CA000