View vehicle applications
Fitment notes and restrictions
Description
Replace rear suspension deflection with a precise spherical joint
SPL RKB F3X replaces the compliant factory rear traction-arm knuckle bushings on supported BMW F2X and F3X chassis with low-friction, PTFE-lined spherical bearings. The change reduces bind through suspension travel and limits bushing movement under load while retaining a housing sized for the original knuckle location.
Key Features
- SPL RKB F3X is supplied as a matched pair for one vehicle
- Low-friction, PTFE-lined spherical bearings
- Large FK bearing selected to support service life and control noise, vibration, and harshness
- 6061-T6 aluminum bearing housings
- CNC-machined to a stated tolerance of plus or minus 0.001 inch
- Replaces BMW part number 3336792551
- Made in the USA
Application details and restrictions
| Years | Make | Application | Chassis |
|---|---|---|---|
| 2010-2019 | BMW | Supported 1 Series and 2 Series applications | F20, F21, F22, F23 |
| 2011-2019 | BMW | Supported 3 Series and 4 Series applications | F30, F31, F32, F33, F34, F35, F36 |
Confirm the chassis, model year, and rear traction-arm-to-knuckle bushing location before ordering. This pair replaces the lower-control-arm bushing at the rear knuckle and is not a complete rear suspension bushing kit.
Specifications
| Detail | Value |
|---|---|
| Manufacturer Part Number | SPL RKB F3X |
| Product Type | Rear traction-arm knuckle bushing pair |
| Position | Rear knuckle |
| Bearing | PTFE-lined FK spherical bearing |
| Housing Material | 6061-T6 aluminum |
| Machining Tolerance | Plus or minus 0.001 inch |
| Replaces BMW Number | 3336792551 |
| Country of Manufacture | United States |
What's Included
- One pair of SPL RKB F3X rear traction-arm knuckle bushing assemblies
- Two installed spherical bearings and application-specific inner sleeves as pictured by SPL Parts
About SPL Parts
SPL Parts develops precision suspension hardware for street, track, and motorsport use. Its spherical-bearing components are designed to reduce unwanted compliance while preserving suspension articulation in the supported factory mounting location.
Related Parts
- No related product is linked because rear arms, toe links, and alignment hardware must match the exact BMW chassis and suspension configuration.
FAQ
What is the SPL RKB F3X?It is a pair of spherical-bearing bushings for the supported BMW rear traction-arm-to-knuckle mounting location.
How many bushings are included?SPL Parts supplies the product as a pair for one vehicle.
What factory component does it replace?It replaces the rubber bushing that connects the lower control arm or traction arm to the rear knuckle, including BMW reference number 3336792551.
Will it fit every BMW F-series chassis?No. Fitment is limited to the listed F20 through F23 and F30 through F36 chassis and supported model years.
Why use a spherical bearing here?The spherical joint reduces rubber-bushing deflection and bind as the suspension moves under load.
What is the housing made from?The housing is CNC-machined from 6061-T6 aluminum.
Is the product sold as a complete rear bushing kit?No. It is the pair for the rear traction-arm knuckle location only.
Should the vehicle be aligned after installation?Inspect rear alignment after installation and complete a professional alignment when measurements are outside the vehicle manufacturer's specifications.
Installation Instructions
- Confirm the BMW chassis, model year, mounting location, and SPL RKB F3X before disassembly.
- Review the current SPL Parts guidance and the applicable BMW service procedure for rear suspension removal, support points, and fastener replacement.
- Support the vehicle and suspension safely, then remove only the components required to access the rear traction-arm knuckle bushing.
- Use correctly sized press tooling so removal and installation loads do not pass through or damage the spherical bearing.
- Reassemble with serviceable hardware and tighten fasteners using the current BMW torque procedure for the exact vehicle.
- Verify bearing articulation, wheel and brake clearance, suspension travel, and rear alignment before road use.
California Proposition 65 Warning: Cancer and reproductive harm - www.P65Warnings.ca.gov.
