SPL Parts 2012+ BMW 3 Series/4 Series xDrive F3X Front Caster Rod Bushings (Non-Adjustable)

Eliminate Rubber Bushing Deflection on Your BMW F3X xDrive with Spherical Caster Rod Bearings

The SPL CRBN F3IX replaces the factory rubber caster rod bushings on 2012 and newer BMW 3 Series and 4 Series xDrive models with precision-machined spherical bearings, eliminating the deflection and compliance inherent in OEM rubber. Engineered specifically for xDrive (AWD) chassis including the F30, F31, F32, F33, F34, and F36, these are non-adjustable direct-replacement bushings that maintain factory caster geometry rather than offering offset adjustment. Full fitment spans the 2012-2019 BMW F30 3 Series xDrive (320i, 328i, 330i, 335i, 340i xDrive) and the 2014-2019 BMW F32/F36 4 Series xDrive (428i, 430i, 435i, 440i xDrive). Sold as a pair.

Features

• Massive 1 inch FK Racing spherical bearings with self-lubricating Teflon/PTFE liners for low-friction articulation
• CNC machined 6061-T6 billet aluminum bearing housings with outer knurl for secure press fit
• Eliminates rubber bushing deflection under braking, cornering, and hard acceleration loads
• Maintains consistent suspension geometry and caster angle through the full range of suspension travel
• Direct-fit, non-adjustable replacement preserving factory caster alignment (no offset, no adjustment required)
• Suitable for street driving and track use
• Sold as a pair (driver and passenger sides)
• Made in the USA

Fitment

Specifications

What Is Included

• 2x CNC machined billet 6061-T6 aluminum caster rod bushing housings
• 2x FK Racing 1 inch spherical bearings with self-lubricating Teflon/PTFE liner
• Hardware for installation

Frequently Asked Questions

What is the difference between the SPL CRBN F3IX and the adjustable caster arm version?
The non-adjustable SPL CRBN F3IX swaps factory rubber for FK Racing spherical bearings while retaining the factory caster rod length and geometry, making it a true direct drop-in. The adjustable version uses an offset bearing spacer design that shifts the caster rod attachment point to dial in additional positive caster beyond the factory setting. If your goal is simply to eliminate rubber deflection without changing alignment specs, this part is the correct choice. If you need caster adjustment capability beyond factory range for a track build, the adjustable variant is the better fit.

Will these caster rod bushings fit a RWD (non-xDrive) BMW F30 3 Series?
No. This part is designed exclusively for xDrive (AWD) F30, F31, F32, F33, F34, and F36 chassis. The front caster rod geometry and bushing housing dimensions on the xDrive platform differ from the rear-wheel-drive F30. SPL Parts offers a separate SKU, the SPL CRBN F3X, for non-xDrive RWD applications. Verify your drivetrain configuration before ordering.

Do these caster rod bushings require any alignment after installation?
Because these are non-adjustable and maintain factory caster geometry, they do not themselves change your caster angle. A four-wheel alignment check is still recommended after any front suspension component replacement to confirm that caster, camber, and toe remain within spec.

Will aftermarket caster rod bushings void my BMW factory warranty?
Under the Magnuson-Moss Warranty Act, a dealer cannot void your factory warranty solely because you installed an aftermarket part. The dealer must demonstrate that the aftermarket part directly caused the failure in question. Any warranty claim related to suspension components may receive additional scrutiny, and consulting with your dealer or a qualified attorney for guidance specific to your situation is advisable.

What bearing brand does SPL Parts use in these bushings?
SPL Parts uses 1 inch FK Racing spherical bearings with a chemically bonded self-lubricating Teflon/PTFE liner. FK Racing manufactures bearings in the USA and their Teflon-lined units are widely used in professional motorsport. The PTFE liner operates reliably from -65 degrees F to 325 degrees F, covering the full range of street and track environments.

How do spherical caster rod bushings improve handling compared to OEM rubber?
The factory rubber bushings flex under lateral and longitudinal load, allowing the caster rod attachment point to move slightly under load. This compliance introduces a delay in steering response, causes inconsistent brake bias under threshold braking, and makes suspension geometry less predictable mid-corner. A spherical bearing articulates freely through suspension travel while eliminating all lateral play, resulting in more direct turn-in response and consistent front-end behavior under braking.

Are these bushings street legal and DOT compliant?
The SPL CRBN F3IX is a suspension bushing replacement and is not subject to DOT certification requirements that apply to safety-critical components such as tires or brake hardware. They are suitable for street use and are used regularly on daily-driven vehicles as well as track day cars. California residents should note the Prop 65 warning below.

Can these be used on a dedicated track car or only for street driving?
These bushings are equally suited to dedicated track builds and street-driven vehicles. The FK Racing 1 inch spherical bearings with Teflon liners are rated for continuous high-load applications and resist the heat, shock loads, and contamination common in competition environments. SPL Parts designs all FKS Series components for motorsport use, and these bushings see regular use in time attack, HPDE, and club racing on the BMW F30 platform.

Installation Instructions

1. Safely raise the vehicle and support it on jack stands rated for the vehicle weight. Remove the front wheels on both sides.
2. Locate the front caster rod (also referred to as the front tension rod) on both sides. It runs longitudinally from the front subframe to the lower control arm area.
3. Support the front lower control arm with a floor jack to relieve suspension load from the caster rod before loosening any fasteners.
4. Remove the bolt and nut securing the caster rod to the front subframe bracket. Note the orientation and torque spec for reinstallation (typically 74 ft-lbs plus an additional 90 degrees for the chassis nut on the F30).
5. Remove the bolt securing the opposite end of the caster rod to the lower control arm or spindle bracket. Keep all hardware organized and labeled by side.
6. Press or drive out the OEM rubber bushings from the caster rod ends using a bench vise, bushing press, or suitable socket. Apply penetrating lubricant if the bushings are difficult to remove.
7. Clean the bore of each caster rod bushing housing to remove any rust, debris, or old bushing material. The bore must be clean and smooth for proper fitment of the new spherical bearing housings.
8. Press each SPL CRBN F3IX spherical bearing housing firmly into the caster rod end. Ensure each housing is fully seated and flush. Use a proper press or vise with flat support plates to avoid damaging the bearing during installation.
9. Verify that the spherical bearing articulates freely through its full range of motion before reinstalling the caster rod.
10. Reinstall the caster rod to the subframe bracket, threading the factory bolt through the inner bearing race. Leave fasteners hand-tight only at this stage.
11. Reconnect the opposite end of the caster rod to the lower control arm bracket using the factory hardware. Thread all fasteners by hand.
12. Raise the lower control arm with the floor jack to simulate ride height before torquing any fasteners. Torquing at full suspension droop can preload the spherical bearing and shorten service life.
13. Torque all fasteners to BMW factory specifications per your service manual for the specific year and chassis.
14. Repeat the complete procedure on the opposite side.
15. Reinstall front wheels and torque lug bolts to specification. Lower the vehicle to the ground.
16. Schedule a four-wheel alignment to verify and set caster, camber, and toe following any front suspension work.

WARNING: This product can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and reproductive harm. For more information go to www.P65Warnings.ca.gov.