The Ultimate Guide to RX8 Suspension Parts: Upgrades, Maintenance, and Buying Tips

Upgrading or replacing suspension parts on a Mazda RX-8 is one of the most effective ways to improve handling, ride comfort, and overall driving enjoyment. Whether you are refreshing worn components or building a track-focused machine, understanding the available options will help you make informed decisions. This guide covers the essential RX8 suspension parts, their functions, and practical advice for choosing the right upgrades.

Shocks and Struts

Shocks and struts control the oscillation of the springs and keep the tires in contact with the road. The RX-8 uses separate shocks and springs front and rear (not coil-overs as standard). When these wear out, the car feels bouncy, loose, or unsettled over bumps.

Replacement vs. Upgrade

Stock shocks are adequate for daily driving but lack the damping needed for spirited driving or track use. Many owners choose to replace worn shocks with performance-oriented units. Options include:

• KYB Excel-G: A direct OEM replacement that restores original ride quality at a reasonable price.
• Bilstein B6: Heavy-duty shocks that offer improved damping without lowering the car.
• Koni Sport (Yellow): Adjustable shocks that allow tuning for street or track. They are popular for RX-8s because they improve body control without harshness.

Lowering Shocks

If you plan to lower the car, make sure the shocks are compatible with shorter springs. Some aftermarket shocks are designed for stock ride height only. Always check manufacturer recommendations.

Springs

Springs support the vehicle's weight and determine ride height and stiffness. RX-8 springs can sag over time, reducing performance and causing uneven tire wear.

Stock vs. Lowering Springs

Stock springs are soft and prioritize comfort. Lowering springs reduce the center of gravity, decrease body roll, and improve cornering. Popular choices include:

• Eibach Pro-Kit: Lowers the car about 1 inch and provides a mild performance boost without sacrificing too much ride quality.
• H&R Sport Springs: More aggressive drop (about 1.3 inches) and stiffer rates, suited for autocross or track use.
• Mazdaspeed (OEM performance): A factory upgrade option that lowers the car slightly while maintaining compliance.

Coil-Over Systems

Coil-overs combine springs and shocks into a single unit, offering adjustability in ride height, damping, and sometimes camber. They are ideal for serious performance enthusiasts. Notable brands for the RX-8 include:

• Ohlins Road & Track: Premium quality with separate adjustment for compression and rebound. Excellent for track days.
• BC Racing BR Series: Affordable and reliable, with 30 levels of damping adjustability.
• KW Variant 3: High-end German engineering with stainless steel threads and fine-tuning capabilities.

Coil-overs require more maintenance and can be harsh on rough roads. They are best for drivers who prioritize handling over comfort.

Sway Bars (Anti-Roll Bars)

Sway bars reduce body roll during cornering by connecting the left and right suspension. The RX-8 comes with thin factory bars that are adequate but leave room for improvement.

Upgrading sway bars is one of the most cost-effective handling mods. They make the car flatter in corners without a significant sacrifice in ride quality. Options:

• Racing Beat: Offers a 1.125-inch front and 1.0-inch rear hollow bar set. They are designed specifically for the RX-8 and reduce understeer.
• Cusco: Solid bars with multiple adjustment holes for fine-tuning. Stiffer than stock but still streetable.
• Mazdaspeed: OEM performance bars that are thicker than stock and come with reinforced bushings.

When upgrading sway bars, also upgrade the end links and bushings to handle the increased stress. Polyurethane bushings are a common upgrade.

Bushings

Bushings isolate vibrations and allow controlled movement between suspension components. Over time, rubber bushings harden, crack, and cause play. Replacing them with polyurethane or spherical units sharpens handling.

• Front Control Arm Bushings: Worn ones cause vague steering and wandering. Polyurethane replacements from SuperPro or Energy Suspension provide tighter feel.
• Rear Subframe Bushings: The RX-8 rear subframe can flex under load. Stiffer bushings reduce rear-end squat and improve traction.
• Sway Bar Bushings: Upgrade to polyurethane when replacing sway bars for consistent performance.

Bushing replacement is labor-intensive. Many owners opt for aftermarket upper control arms with integrated spherical bearings (like those from Ikeya Formula) to eliminate bushing compliance entirely. However, this increases noise and vibration.

Control Arms and Ball Joints

The RX-8 has multi-link rear suspension with several control arms. Worn ball joints or bent arms cause alignment issues and uneven tire wear.

• Lower Control Arms: Often replaced when lowering the car to correct camber. Adjustable arms from SPC or Megan Racing allow precise alignment.
• Upper Control Arms (Rear): Not adjustable from the factory. Aftermarket options allow camber adjustment for lowered cars.
• Ball Joints: Replace as a unit with the control arm if pressed-in type. Moog offers quality replacements.

Strut Tower Braces

While not strictly suspension, a strut tower brace connects the front shock towers, reducing chassis flex. This improves steering response and consistency. The RX-8 already has a factory brace, but aftermarket ones (like Cusco or AutoEXE) are stiffer and lower-profile for engine bay clearance.

Alignment and Tuning

After any suspension work, a proper alignment is essential. The RX-8 is sensitive to alignment settings. A common street setup is:

• Front: -1.0 to -1.5 degrees camber, 0 toe
• Rear: -1.5 to -2.0 degrees camber, 1/16" toe-in total Track-oriented setups use more negative camber. Always have a technician who is familiar with the RX-8 perform the alignment.

Practical Recommendations

For a daily-driven RX-8 with occasional spirited driving:

• Replace worn shocks with Bilstein B6 or Koni Sport
• Add Eibach Pro-Kit springs (if lowering is desired)
• Upgrade sway bars to Racing Beat or Cusco
• Replace bushings with SuperPro polyurethane as they wear

For a dedicated track car:

• Install coil-overs (Ohlins or KW)
• Use adjustable control arms for camber and toe
• Upgrade to spherical bearings in key locations (rear subframe, front lower arms)
• Add a stiffer rear sway bar and possibly a front sway bar

Always prioritize safety: inspect ball joints, tie rods, and wheel bearings when working on suspension. If you are unsure, consult a professional mechanic who knows rotary cars.

Choosing the right RX8 suspension parts comes down to balancing your driving goals with comfort and budget. Focus on shocks and sway bars first—they offer the most noticeable improvement. Then move to springs, bushings, and alignment. With careful selection, you can transform the handling of your RX-8 into something truly special.