KYB 551105 Shock Absorber - Rear

KYB Gas-a-Just Rear Shock for Mazda 3 and Mazda 5

The KYB Gas-a-just 551105 is a rear suspension shock absorber built for Mazda applications that need firmer control and consistent damping. Its monotube design separates gas and oil for quick response and fade-resistant operation during everyday driving and heavier-duty use.

Key Features

• Monotube construction delivers up to 25% more damping performance than original equipment shocks.
• Engineered with valving and components specifically for Mazda vehicles.
• High-pressure gas design supports vehicles that work, tow, or run larger tires and wheels.
• Air-free hydraulic working chamber improves responsiveness and control.
• Triple chrome plated piston rod helps reduce seal wear and fluid leakage.
• Higher gas pressure improves steering response and suspension reaction.
• Supports proper suspension behavior for electronic safety systems that rely on OE suspension performance.

Product Details

This KYB Gas-a-just shock absorber uses a two-chamber monotube layout with a floating piston and high-pressure nitrogen gas to maintain stable damping under changing road conditions. The design is intended to deliver a comfortable ride in normal driving while adding immediate performance when the suspension is loaded or working harder. Part number 551105 is a direct-fit rear shock option for Mazda 3 and Mazda 5 rear applications, and it cross-references Monroe Shocks & Struts 5607 for the same application.

What It Helps Correct

• Excessive rear-end bounce after bumps or dips
• Reduced steering response from worn rear shocks
• Fade in damping performance during repeated suspension movement
• Fluid leakage related to worn piston rod sealing surfaces
• Loss of control on Mazda 3 or Mazda 5 rear suspension applications

Installation Notes

Compatible With 2004-2009 Mazda 3, rear; 2006-2010 Mazda 5, rear; and 2012-2015 Mazda 5, rear. For reduced noise and vibration, KYB recommends replacing the rear strut mount with part number SM5723. Verify compressed length, extended length, stroke, and mount style before installation. Part number 551105 is designed for rear placement only.

Quality Assurance

KYB designs the Gas-a-just line for performance-focused damping control and OE-style fitment on Mazda applications. The monotube construction, high-pressure gas separation, and chrome piston rod are used to support consistent operation and long-term suspension performance.