Whiteline Front Radius Rod to Chassis Caster Correction Bushing – 2006-2012 BMW 3 Series Models

Add Caster to Your E90 BMW for Improved Steering Feel
The Whiteline KCA430 is an offset radius rod to chassis bushing for the 2006-2012 BMW 3 Series (E90/E92/E93) that increases front caster beyond the factory alignment range. Additional caster improves straight-line stability, sharpens turn-in response, and provides more camber gain during cornering for better front tyre contact at the limit. It’s a geometry correction that directly improves how the E90 responds to steering inputs.

DETAILS

• Offset bushing adds front caster to E90/E92/E93 BMW 3 Series
• Improves straight-line stability and turn-in response
• Provides additional camber gain during cornering
• Correct for lowered E9x applications where caster is lost
• Direct replacement at radius rod to chassis position

Why Caster Matters on the E90
Caster is the angle of the steering axis as seen from the side. More caster produces stronger self-centering, better straight-line stability, and — most importantly for handling — more camber gain as the wheel turns. When the outside front wheel turns in during a corner, more caster means it gains more negative camber, keeping the contact patch loaded correctly. The E90’s caster spec is adequate from the factory, and the KCA430 improves on it.

Critical for Lowered E90 Applications
Lowering an E90 BMW reduces caster — the geometry changes as the suspension height changes. Cars that have been lowered with springs or coilovers often fall outside the factory caster spec, producing vague steering center and reduced stability. The KCA430 restores and improves caster to account for the lower ride height.

Alignment After Installation
After installing caster correction bushings, a four-wheel alignment is required to set the front geometry to the new caster range. The alignment shop should confirm caster, camber, and toe at the lowered ride height. The improvement in steering feel and stability will be immediately noticeable after alignment.

Why Choose Whiteline

Whiteline has been engineering suspension components from their facility in Australia since 1979. Every product in their catalog is developed with a clear goal: measurable improvement in handling, stability, and tyre contact. Whiteline’s polyurethane bushings, sway bars, control arms, and alignment correction kits are engineered using finite element analysis and validated on track before they reach the market. Their components are direct-fit, bolt-on solutions designed for enthusiasts who want real performance gains without fabrication or custom work.

The RallySport Take

An effective and precise geometry correction for the E90 BMW. If your lowered 3 Series feels vague on center or lacks the steering precision the car is supposed to deliver, caster correction is one of the first things to address.

What’s in the Box

• Offset bushing adds front caster to E90/E92/E93 BMW 3 Series
• Improves straight-line stability and turn-in response
• Provides additional camber gain during cornering
• Correct for lowered E9x applications where caster is lost
• Direct replacement at radius rod to chassis position

Fitment