240sx S13 Rear Lower Control Arms

Alright, let's dive deep into the world of S13 240SX rear lower control arms (RLCAs). These unassuming pieces of metal play a crucial role in your car's handling, especially if you're planning on lowering it, drifting, or just want to improve overall performance. We're going to cover everything from the stock arms' limitations to aftermarket options and installation considerations.

Understanding the Rear Lower Control Arm's Role

The RLCA connects the rear hub assembly to the chassis. Think of it as a vital link in the suspension system. Its primary functions include:

Maintaining Wheel Position: The RLCA ensures the rear wheel stays where it should be relative to the chassis. This is essential for proper handling and tire wear.
Controlling Camber: While not always the primary adjustment point, the RLCA length significantly impacts the camber angle. Camber is the angle of the wheel relative to vertical when viewed from the front or rear of the vehicle. Negative camber (top of the tire tilted inward) is often desirable for improved grip during cornering.
Transmitting Forces: The RLCA transmits braking, acceleration, and cornering forces from the hub to the chassis and vice-versa. This means it needs to be strong and durable.

The Stock S13 RLCA: Strengths and Weaknesses

The factory S13 RLCA is a stamped steel design with rubber bushings. It's adequate for stock ride height and moderate driving. However, it suffers from several limitations when you start modifying the car:

Flex: Stamped steel, especially after years of use and potential rust, can flex under heavy loads. This flex reduces responsiveness and can lead to inconsistent handling.
Bushing Deflection: The rubber bushings are designed to absorb vibrations and reduce noise, but they also allow for significant deflection under load. This deflection negatively impacts handling precision and can feel "squishy" or vague.
Non-Adjustability: The stock RLCA is a fixed length. This means you can't easily adjust camber to compensate for lowering or to optimize for different driving styles.
Durability Concerns: Older cars, especially those that have seen harsh winters, might have corroded and weakened RLCAs.

Why Upgrade to Aftermarket RLCAs?

Upgrading your RLCAs offers several significant advantages:

Increased Strength and Rigidity: Aftermarket RLCAs are typically made from stronger materials like high-strength steel or aluminum. This reduces flex and improves handling precision.
Improved Bushings: Most aftermarket RLCAs use stiffer bushings, such as polyurethane (poly) or spherical bearings (heim joints). Poly bushings offer a good balance of performance and comfort, while spherical bearings provide the ultimate in stiffness and responsiveness (but can transmit more noise and vibration).
Camber Adjustment: This is the biggest selling point for many. Adjustable RLCAs allow you to dial in your camber settings for optimal handling and tire wear, especially after lowering the vehicle. Lowering the car naturally introduces negative camber. Adjustable arms give you control to fine tune for specific needs.
Enhanced Handling: The combined effect of increased strength, stiffer bushings, and camber adjustment results in a more responsive, predictable, and confidence-inspiring handling experience.
Improved Durability: Quality aftermarket RLCAs are built to last and can withstand the stresses of aggressive driving.

Types of Aftermarket RLCAs

Here's a breakdown of the common types you'll encounter:

Fixed Length RLCAs with Upgraded Bushings

These arms are the same length as the stock arms but feature stronger construction and upgraded bushings. They're a good option if you're not planning on lowering your car significantly or if you just want to improve bushing performance. These offer minimal camber adjustability.

Adjustable RLCAs with Polyurethane Bushings

This is a popular choice for street and track cars. The adjustable length allows for camber adjustments, while the polyurethane bushings provide a good balance of performance and comfort. Poly bushings are generally more compliant than spherical bearings, absorbing some vibration and harshness. They're also more forgiving in terms of maintenance; spherical bearings need regular cleaning and lubrication.

Adjustable RLCAs with Spherical Bearings

Also known as heim joints, spherical bearings offer the ultimate in stiffness and responsiveness. They eliminate bushing deflection entirely, resulting in incredibly precise handling. However, they transmit more noise and vibration into the cabin and require regular maintenance to prevent binding and premature wear. These are best suited for dedicated track cars or those willing to sacrifice some comfort for maximum performance.

Material Considerations: Steel vs. Aluminum

RLCAs are typically made from either steel or aluminum. Both materials have their pros and cons:

Steel: Strong, durable, and relatively inexpensive. Steel RLCAs are a good choice for most applications, especially if you're concerned about cost or durability. However, they are heavier than aluminum.
Aluminum: Lighter than steel, which can improve handling and acceleration. Aluminum RLCAs can also be visually appealing. However, they are generally more expensive than steel and may be more susceptible to damage from impacts. The specific alloy used is important; higher-grade alloys like 7075 are significantly stronger than lower-grade alloys.

Installation Considerations

Installing RLCAs is a relatively straightforward process for experienced DIYers. However, there are a few key things to keep in mind:

Safety First: Always use jack stands to support the car securely. Never work under a car supported only by a jack.
Penetrating Oil: Soak the old RLCA bolts with penetrating oil (like PB Blaster) well in advance of attempting removal. These bolts are often seized due to rust and corrosion.
Loosen Before Lifting: Loosen the lug nuts on the rear wheels before lifting the car. This makes it easier to remove the wheels once the car is in the air.
Remove the Old RLCAs: Disconnect the shock absorber and sway bar end link (if applicable) from the RLCA. Then, remove the bolts securing the RLCA to the hub and chassis. You may need to use a rubber mallet to persuade the RLCA to come loose.
Install the New RLCAs: Install the new RLCAs in the reverse order of removal. Make sure to use new bolts and nuts if possible. Applying anti-seize compound to the threads is a good idea.
Torque Specifications: Torque all bolts to the manufacturer's specifications. These can be found in your car's service manual or online. Improperly torqued bolts can lead to component failure.
Alignment: Crucially important! After installing new RLCAs, you *must* get a professional wheel alignment. This is essential to ensure proper handling and tire wear.
Adjustable Arm Setup: If you're installing adjustable RLCAs, start with the arms set to the approximate length of the stock arms. This will give you a baseline for your alignment. The alignment shop will then fine-tune the camber to your desired settings.
Check Bushing Orientation: Some aftermarket bushings have a specific orientation. Make sure to install them correctly according to the manufacturer's instructions.
Grease Poly Bushings (If Applicable): Polyurethane bushings often require lubrication to prevent squeaking. Use a grease specifically designed for poly bushings.

Choosing the Right RLCA for Your Needs

The best RLCA for your S13 depends on your budget, driving style, and goals. Consider these factors:

Budget: Aftermarket RLCAs range in price from a few hundred dollars to over a thousand dollars.
Driving Style: If you're primarily a street driver, adjustable RLCAs with polyurethane bushings are a good option. If you're a serious track enthusiast, adjustable RLCAs with spherical bearings may be a better choice.
Lowering: If you're planning on lowering your car significantly, adjustable RLCAs are essential for correcting camber.
Brand Reputation: Research different brands and read reviews to ensure you're buying a quality product. Reputable brands often use better materials and manufacturing processes.

Final Thoughts

Upgrading your S13's rear lower control arms is a worthwhile modification that can significantly improve handling and performance. By understanding the different types of RLCAs, materials, and installation considerations, you can choose the right arms for your needs and enjoy a more responsive and predictable driving experience. Remember to prioritize safety during installation and always get a professional wheel alignment afterward. Good luck!