SPC Performance 81381 Audi A4 Control Arms Left

The SPC Performance 81381 is a forged aluminum adjustable front upper control arm for the left-hand side of the Audi B9 platform. Designed as a direct replacement for the factory fixed-length arm, this arm provides ±1.5° of front camber and caster adjustment — essential for correcting alignment after a suspension lowering or for dialing in performance-oriented settings.

Audi's unique multi-link suspension geometry creates a Virtual SAI (Steering Axis Inclination), and while Audi does not publish an OEM caster specification, SPC Performance recommends 5° to 6° of caster for optimal straight-line tracking and steering return-to-center behavior. The OE-style booted ball joints and bonded rubber bushings preserve factory ride quality and noise, vibration, and harshness (NVH) characteristics, making this arm equally suitable for daily driving and performance use.

Key Features:

• Forged 6061-T6 aluminum construction — maximum strength with minimum weight
• ±1.5° camber and caster adjustability via large 18mm threaded adjuster links
• OE-style maintenance-free booted ball joints for long service life and NVH compliance
• Bonded rubber bushings maintain factory ride and handling parameters
• Large 18mm threaded adjuster links for precise, repeatable adjustments
• Replacement pinch bolts included

This part covers the left-hand (LH) side only. For the right-hand side, use SPC part #81382. To adjust both sides, use the pair kit #81383. Professional alignment is recommended following installation.