SPL Parts SPL CRBN F3IX Front Caster Rod Bushings for 10-20 BMW F2X/F3X xDrive

Vehicle Fitment

• 2010-2019 BMW 1 Series (F20/F21, xDrive, M135i xDrive N55 3.0L I6, M140i xDrive B58 3.0L I6)
• 2014-2019 BMW 2 Series (F22/F23, xDrive, 228i xDrive N20 2.0L I4, 230i xDrive B46 2.0L I4, M235i xDrive N55 3.0L I6, M240i xDrive B58 3.0L I6)
• 2012-2019 BMW 3 Series (F30/F31/F34/F35, xDrive, 320i xDrive N20 2.0L I4, 328d xDrive N47 2.0L I4 Diesel, 328i xDrive N20 2.0L I4, 330i xDrive B46 2.0L I4, 335i xDrive N55 3.0L I6, 340i xDrive B58 3.0L I6)
• 2014-2020 BMW 4 Series (F32/F33/F36, xDrive, 428i xDrive N20 2.0L I4, 430i xDrive B46 2.0L I4, 435i xDrive N55 3.0L I6, 440i xDrive B58 3.0L I6)

Fitment Notes

• Fits xDrive (AWD) vehicles only - does not fit RWD variants of any F2X or F3X chassis.
• BMW F20/F21 1 Series is a European/global market chassis and was not sold in North America; all listed xDrive variants are compatible where available.
• OEM caster rod arms are not included - this is a bushing replacement kit only; the factory arms must be reused.
• Replaces OEM BMW part number 31126854729.

Features

• FKS Series non-adjustable design replaces factory rubber bushings with low-friction, articulating spherical bearings for zero bushing deflection.
• Massive 1" FK Racing spherical bearings with self-lubricating Teflon liners for maximum durability and consistent articulation.
• 6061-T6 aluminum bearing housing with outer knurl for secure press-fit retention in the OEM caster rod.
• Eliminates bushing deflection under load to maintain optimum suspension geometry during cornering, braking, and acceleration.
• Improves steering feedback and braking precision by keeping the front suspension geometry consistent throughout the suspension travel.
• Drop-in non-adjustable design maintains factory caster angle - no alignment recalibration beyond a standard alignment check required.
• Precision CNC-machined components manufactured entirely in the USA to exacting tolerances.
• Suitable for daily street driving through to dedicated track use - no sacrifice in ride quality for street applications.
• Sold as a matched pair to ensure balanced front suspension performance on both sides.

Specifications

• Position: Front, Left and Right (pair)
• Type: Non-Adjustable Spherical Caster Rod Bushings (FKS Series)
• Bearing Size: 1" FK Racing spherical bearings
• Bearing Liner: Self-lubricating PTFE (Teflon)
• Housing Material: 6061-T6 Aluminum with outer knurl
• Drivetrain: xDrive (AWD) only
• OEM BMW Part Number Replaced: 31126854729
• Country of Manufacture: USA
• Quantity: Sold as a pair (2 bushings)

Included Components

• 2x SPL Parts FKS Series Non-Adjustable Front Caster Rod Spherical Bushings (left and right)

Product Description

The SPL Parts SPL CRBN F3IX is a non-adjustable front caster rod bushing kit designed specifically for xDrive-equipped BMW F2X and F3X chassis vehicles, including the 1 Series (F20/F21), 2 Series (F22/F23), 3 Series (F30/F31/F34/F35), and 4 Series (F32/F33/F36). These FKS Series bushings replace the factory rubber caster rod bushings - a known weak point on these platforms - with massive 1" FK Racing spherical bearings featuring self-lubricating Teflon liners. The result is the complete elimination of bushing deflection that causes vague steering feel and inconsistent braking response on the stock suspension. The 6061-T6 aluminum housing is machined with an outer knurl for secure press-fit installation directly into the factory caster rod, requiring no modification to OEM components.

Because these are a non-adjustable drop-in replacement, the factory caster geometry is preserved exactly. This makes the CRBN F3IX an ideal first suspension upgrade for enthusiasts who want sharper, more communicative front-end behavior without the complexity of setting caster angle through an adjustable system. The bearings maintain full articulation through the suspension's range of motion while keeping the front knuckle and spindle precisely located under hard braking and cornering - exactly where factory rubber deflects and loses control. A standard wheel alignment check after installation is recommended but no special alignment setup is required.

The SPL CRBN F3IX is built entirely in the USA to SPL Parts' motorsport-grade standards and is equally suited to high-mileage daily street drivers and dedicated track builds. Whether upgrading a 328i xDrive commuter or a 340i xDrive track car, these bushings deliver a meaningful, immediately noticeable improvement in braking stability and steering feel. Note that OEM caster rod arms are not included - the factory arms are reused with the new spherical bushings pressed in. Sold as a pair covering both the left and right front caster rod positions.