KYB 551116 Suspension Strut - Rear

KYB Gas-a-just Rear Strut for RX-8

The KYB Gas-a-just 551116 is a rear suspension strut built as an OE-style monotube replacement for the 2004-2008 Mazda RX-8. It is engineered to restore original handling response while maintaining a controlled ride in everyday driving.

Gas-a-just is KYB’s monotube product line for vehicles that work harder than standard commuter use, including applications with added load, towing demands, or larger wheels and tires. For the Mazda RX-8, this rear strut helps bring back the chassis control the vehicle was designed to deliver.

Key Features

• Monotube OE replacement design for direct suspension service
• Fits 2004-2008 Mazda RX-8, rear
• High-pressure gas and oil chambers are separated for consistent damping response
• Triple chrome plated piston rod helps reduce seal wear
• Quick gas pressure response supports sharper steering feel
• Supports electronic safety systems by helping the suspension operate as designed
• Part number 551116 for easy identification

Product Details

The KYB Gas-a-just 551116 uses a two-chamber monotube layout with an air-free hydraulic working area and a separate high-pressure nitrogen gas section. That design provides responsive control during normal driving and immediate damping performance when road conditions change. This rear strut is a recommended OEM replacement for the Mazda RX-8 and is listed for 2004-2008 models, excluding SHINKA and Performance Packages. This part cross-references Monroe Shocks & Struts 71123 for the same application.

Common Problems This Strut Can Address

• Excessive rear bounce or oscillation after bumps
• Loose or delayed handling response in the Mazda RX-8
• Reduced control from worn or leaking rear suspension struts
• Uneven ride quality caused by aging damping components
• Loss of chassis stability during braking or cornering

Installation Notes and Tips

Verify rear fitment by year and trim before installation. This strut is listed for 2004-2008 Mazda RX-8 rear applications, excluding SHINKA and Performance Packages. Inspect related suspension components, mounts, and tires before replacing the strut so the new unit can perform correctly. Confirm the upper and lower mount styles match the vehicle’s original configuration.

Quality Assurance

KYB manufactures Gas-a-just as an OE monotube replacement line focused on restoring factory-style control and handling. The 551116 is built with a high-pressure monotube design and a chrome piston rod to support long-term seal durability and consistent damping performance.