SPL Parts Adjustable Front Caster Rod Monoball Bushings

2020–2023 Toyota GR Supra & 2019+ BMW Z4

SPL CRB G29

Overview:

The SPL Parts Adjustable Front Caster Rod Monoball Bushings are precision-engineered suspension components designed to replace the stock rubber bushings in the front caster rods of the Toyota GR Supra (2020–2023) and BMW Z4 (2019+). By swapping out the flexible rubber for low-friction spherical bearings, these bushings eliminate deflection and reduce friction, maintaining optimal suspension geometry under dynamic loads. This upgrade enhances braking stability, steering feedback, and overall handling performance, making it an essential modification for enthusiasts seeking sharper control and improved driving confidence.

Ideal for both street and track use, these bushings provide a direct connection between the suspension components, allowing the front end to respond more precisely to driver inputs and road conditions.

Key Features:

Engineered for durability and adjustability, the SPL Parts Front Caster Rod Bushings offer the following key benefits:

• Replace stock rubber bushings with articulating spherical bearings to eliminate bushing deflection
• Massive 1-inch FK Racing bearings with self-lubricating Teflon liners for smooth operation and longevity
• CNC-machined offset bearing spacers provide +/- 4 degrees of caster adjustment for fine-tuning suspension geometry
• 6061-T6 aluminum bearing housing with outer knurl for secure fitment and corrosion resistance
• Improves braking performance and handling feedback by maintaining consistent caster angles under load
• Designed specifically for the Toyota GR Supra A90 (2020–2023) and BMW Z4 G29 (2019+)
• Made in the USA with precision engineering and high-quality materials
• Sold as a pair for both front caster rods

Construction & Design:

The SPL Parts Adjustable Front Caster Rod Bushings feature a robust construction combining aerospace-grade 6061-T6 aluminum housings with FK Racing’s renowned 1-inch spherical bearings. These bearings incorporate self-lubricating Teflon liners that minimize friction and wear, ensuring smooth articulation and long service life without the need for frequent maintenance. The aluminum housings are CNC-machined for precise tolerances and include an outer knurl to prevent rotation within the control arm.

Offset bearing spacers are also CNC-machined to allow for precise caster angle adjustments of up to +/- 4 degrees, enabling enthusiasts and tuners to dial in suspension settings for improved cornering balance and tire contact patch optimization. This combination of materials and design results in a durable, high-performance bushing that outperforms stock rubber components in both rigidity and responsiveness.

Installation & Fitment:

Installation of the SPL Parts Adjustable Front Caster Rod Bushings requires removal of the factory caster rod bushings and pressing in the new monoball units. These bushings are designed to fit directly into the OEM front caster rods of the Toyota GR Supra A90 (2020–2023) and BMW Z4 G29 (2019+). No modifications to the control arms are necessary, but professional installation with proper tools is recommended to ensure correct fitment and alignment.

Note that the OEM caster rods are not included with this product and must be retained or sourced separately. Detailed installation instructions are available from SPL Parts to guide users through the process.

What’s Included

• Pair of SPL Parts Adjustable Front Caster Rod Monoball Bushings
• CNC-machined offset bearing spacers for caster adjustment
• Installation instructions

Ideal For:

This product is ideal for Toyota GR Supra and BMW Z4 owners who demand improved suspension precision and handling performance. Enthusiasts who participate in spirited driving, track days, or performance upgrades will benefit from the enhanced steering feedback and braking stability provided by these monoball bushings. They are also suitable for anyone looking to replace worn or deteriorated factory rubber bushings with a more durable and adjustable solution.

SPL Parts is a manufacturer specializing in high-performance suspension components, including control arms, toe links, and sway bar endlinks, primarily for vehicles like Nissan 350Z/370Z, GTR, BMW M-Series, Toyota Supra, and Subaru platforms. Their products are designed to enhance handling and stability for both street and track applications, offering adjustability and durability to meet the demands of performance enthusiasts.