Upgrading control arms is one of the most effective modifications an enthusiast can make for track-day performance. While the stock suspension often prioritizes ride comfort and cost, track use demands precise geometry, reduced flex, and the ability to dial in alignment settings that keep tires planted through corners. This article goes beyond the basics, providing in-depth technical insights, brand comparisons, and real-world installation advice to help you choose the right control arms for your track car.

The Role of Control Arms in Suspension Geometry

Control arms are the backbone of your suspension’s kinematics. They locate the wheel hub in relation to the chassis while allowing vertical travel. Every bump, brake application, and cornering load travels through these arms, so their stiffness and geometry directly influence how the tire maintains contact with the pavement.

Camber, Caster, and Toe: The Trio Alignment

Control arms dictate the wheel’s camber angle (tilt in/out), caster angle (steering axis tilt), and toe angle (direction relative to the car centerline). Stock arms often provide fixed geometry that cannot be adjusted beyond factory settings. On track, you typically want increased negative camber in the front for better cornering grip, and sometimes slight toe-out front or toe-in rear for stability. Upgraded arms with adjustable ball joints or eccentric bushings let you fine-tune these settings independently.

How Arm Length and Mount Points Affect Roll Center

The mounting points of control arms determine the suspension’s roll center — the imaginary point around which the car leans during cornering. A lower or higher roll center changes weight transfer and body roll characteristics. Aftermarket control arms may offer adjustable mounting positions to optimize roll center for lowered ride heights, preventing geometry bind and keeping the suspension in its sweet spot under heavy cornering loads.

Key Technical Specifications to Evaluate

Not all control arms are built the same. Here are the critical parameters to compare when shopping for track-duty arms.

Material

Aluminum is the most common upgrade material because it’s lightweight and offers excellent fatigue resistance. 6061-T6 aluminum arms are prevalent. Chromoly steel (4130) is stronger but heavier; it’s often used in race cars where ultimate strength outweighs weight concerns. Avoid mild steel or cast iron unless budget is the only constraint — they add unnecessary unsprung mass that hurts suspension response.

Design and Adjustability

Look for arms that allow adjustment of camber and toe via slotting, eccentric cams, or threaded rod ends. Many high-end arms use spherical bearings (heim joints) for the pivot points, which provide near-zero deflection and allow adjustment. Some arms feature replaceable ball joints so you can change angle without swapping the entire arm.

Bushings

Stock rubber bushings flex significantly under track loads, introducing unwanted compliance that blurs steering feel and causes dynamic alignment changes. Upgraded bushings come in three tiers:

  • Polyurethane: Stiffer than rubber, retains some comfort, but can squeak without proper lubrication. Good for dual-duty cars.
  • Delrin or nylon: Very stiff, little noise reduction, excellent for track-only cars.
  • Spherical bearings: Minimal deflection, maximum feedback, can transmit noise and vibration directly into the chassis. Ideal for pure track machines.

Weight

Every pound of unsprung mass (components not supported by the springs, including control arms) forces the suspension to work harder to maintain tire contact. Lighter control arms improve damping response and reduce wheel hop under braking. Aim for arms that weigh 30-50% less than stock without sacrificing strength.

Upper vs Lower Control Arms: What to Upgrade

Most cars use either a double-wishbone or MacPherson strut front suspension. In double-wishbone setups, both upper and lower control arms can be upgraded. Adjustable upper arms offer camber adjustment; lower arms often provide caster and toe adjustment as well. For MacPherson strut cars, the lower control arm is the primary target for geometry changes, though some kits include adjustable strut-top mounts to mimic upper arm adjustability.

Rear control arms vary by platform. Solid-axle cars use trailing arms and panhard rods; independent rear suspensions (IRS) often have multiple links. Focus on arms that control camber and toe in the rear, as these have a huge impact on traction out of corners.

Bushing Material Comparison for Track Use

Choosing the right bushing type is as important as the arm itself. Here’s a breakdown of how each material behaves on track:

  • Rubber: Best for noise isolation but too soft for sustained high-g loads. Heat cycling degrades them quickly.
  • Polyurethane: A popular middle ground. Provides a noticeable handling improvement over rubber with manageable NVH. Requires periodic greasing to prevent binding.
  • Spherical bearings: Deliver the tightest steering response and infinite adjustability. They need regular cleaning and may require replacement after extended use due to wear. Many track builders choose arms with replaceable rod ends.
  • Monoball (aka race bearings): A hybrid design that places a spherical bearing inside a metal housing with dust boots. More durable than open rod ends, but still transmits road noise.

Alignment Adjustability and Track Performance

Track alignment is rarely static. As you push harder, you may need to tweak camber for tire temperature balance or toe for corner entry stability. Adjustable control arms let you experiment with setups without guessing. A common track-friendly alignment might be:

  • Front camber: -2.5° to -3.5°
  • Rear camber: -1.5° to -2.0°
  • Front toe: 0 to slight toe-out (1/16”)
  • Rear toe: slight toe-in (1/8”)

These numbers vary per car and tire compound. Adjustable arms make it possible to dial in such specs without slotting factory subframes or using shims.

The following brands have proven themselves on track and are known for precision manufacturing, robust materials, and support for a wide range of vehicles.

BC Racing

BC Racing offers adjustable control arms that pair well with their coilover suspensions. Their arms use 6061 aluminum with spherical bearings or polyurethane bushings. Prices are moderate, and fitment covers many European and Japanese platforms. They are a solid choice for drivers who want a complete suspension system from one brand.

Whiteline

Whiteline is an Australian company that specializes in suspension geometry correction. Their control arms are designed with adjustable caster and camber capabilities, often using eccentric bushings rather than rod ends, which reduces noise. Whiteline arms are popular on Subarus, BMWs, and Mazda Miatas. Their “anti-lift/squat” kits for rear control arms improve traction under acceleration and braking.

SPC Performance

SPC focuses on alignment adjustability without sacrificing ride quality. Their arms feature patented “eccentric camber adjustment” that allows large ranges of camber change using a threaded ball joint housing. Many OEM technicians use SPC arms to bring lowered cars back into factory alignment specs, while track drivers use them to achieve aggressive negative camber. They are a great fit for daily-driver-turned-track-car.

Voodoo13

Voodoo13 is known for premium billet aluminum control arms targeted at track and drifting. Their arms are CNC-machined from 6061-T6 with replaceable heim joints and custom-length adjusters. They offer full replacement kits for many Nissan, Toyota, and Honda platforms. Voodoo13 arms are pricier but deliver race-grade stiffness and precision.

Raceland

Raceland provides budget-friendly control arms that still offer adjustability and improved bushings. Their arms are often made from chromoly steel, which is heavier than aluminum but very strong. They are a good entry point for enthusiasts on a tight budget who want to experience the benefits of adjustable geometry without spending thousands. Pair with a quality alignment to get the most out of them.

Hardrace

Hardrace (Hardrace Australia) manufactures a wide range of suspension components including control arms with polyurethane or spherical bushings. Their arms are well-regarded for durability and are available for many Asian and European models. They offer both front and rear kits with roll-center correction for lowered cars.

Megan Racing

Megan Racing produces adjustable control arms for many popular platforms. They use bright red powder-coated steel with spherical bearings. Price points are competitive, making them a common choice for track-day drivers who want to save weight and gain adjustability.

Installation Considerations and Tips

Prepare the Work Area

Jack the car securely on four stands, remove wheels, and support the lower arm with a jack to prevent spring tension from causing injury. Spray all rusted bolts with penetrating oil a day before.

Tightening Order

Do not tighten the control arm bolts to final torque with the suspension at full droop. Instead, set the car on the ground (or use a lift to put the suspension at ride height) and then tighten. This prevents the bushings from being preloaded, which would cause binding and early failure.

Torque Specifications

Use a torque wrench. Over-tightening can strip threads or crack aluminum arms; under-tightening can cause clunks and alignment shifts. Typical ranges: 50-80 ft-lb for chassis bolts, 40-60 ft-lb for ball joint nuts. Check manufacturer specs.

Post-Install Alignment

Immediately after installing new control arms, get a professional alignment. Drive the car 10-20 miles first to settle the bushings if using polyurethane or rubber. For spherical bearings, alignment can be done right away because there is no settling. Have the technician set your track alignment and mark all adjustments for easy future replication.

Common Mistakes When Upgrading Control Arms

  • Ignoring roll center correction: Lowering a car without adjusting the control arm mounts can drop the roll center too much, leading to excessive body roll and unstable handling. Choose arms that correct roll center geometry for your ride height.
  • Using too much bushing stiffness: Spherical bearings in a street-driven track car can become unbearable on rough roads and dramatically increase NVH. Match bushing type to your usage — polyurethane is often the best compromise.
  • Skipping the alignment: Adjustable arms are useless (and dangerous) without a proper alignment. Dial in factory specs first, then dial in track settings incrementally.
  • Mixing brands incorrectly: Using one brand for upper arms and another for lower can create geometric conflicts if the bushing types or pivot locations differ. Stick with matched sets when possible.
  • Over-tightening ball joints or heim joints: Heim joints need to be torqued to spec and often require a jam nut. Over-tightening can bind the bearing and limit articulation.

Cost vs Performance: Making the Right Choice

Control arms range from $150 per arm for basic adjustable steel units to over $800 per arm for full billet aluminum with spherical bearings. The performance gains are real, but diminishing returns set in quickly. For a track-day car that sees 5-10 events a year, a mid-range set from Whiteline, SPC, or Hardrace (around $400-600 per pair) will deliver 90% of the benefit at half the price of top-tier race arms. Invest the savings into alignment time, high-quality tires, and track day fees — those will improve lap times just as much.

For serious competitors, premium brands like Voodoo13 or custom-built arms from race shops offer the ultimate in weight savings, stiffness, and adjustability. However, those arms often require more frequent inspection and replacement of spherical bearings.

Conclusion

Upgrading control arms transforms a street car into a track-capable machine by unlocking precise alignment, reducing compliance, and improving driver feedback. Focus on material, adjustability, and bushing type that matches your driving goals. Whether you choose a budget-friendly set from Raceland or precision arms from Voodoo13, the key is to install them correctly and follow through with a professional alignment. Your lap times — and your tires — will thank you.

For further reading on suspension geometry fundamentals, check out Racecar Engineering’s guide to roll centers. To see how alignment settings affect tire temperature, Tire Rack’s alignment tech page is a helpful resource. And for brand-specific details on Whiteline products, visit Whiteline’s official site.