KYB 551121 Suspension Strut - Front

KYB Gas-a-Just Front Strut for GM Trucks

The KYB Gas-a-just 551121 is a front suspension strut built as an OE-style monotube replacement for full-size GM trucks and SUVs. It is designed for vehicles that work, tow, and run larger wheels and tires, with responsive damping that helps restore original steering and handling feel.

Compatible With 2007-2014 Chevrolet Tahoe, 2007-2014 GMC Yukon, 2007-2014 Chevrolet Suburban 1500, and other listed GM applications, this front strut uses a high-pressure monotube design to separate gas and oil for consistent response. The KYB Gas-a-just 551121 is a direct-fit suspension service part for drivers replacing worn front struts on select Cadillac, Chevrolet, and GMC models.

Key Features

• OE-style monotube replacement for front suspension service
• High-pressure nitrogen gas chamber for quick response and fade-resistant operation
• Air-free hydraulic working area for control and road feel
• Triple chrome plated piston rod helps reduce seal wear
• Built for trucks and SUVs that tow, haul, or use heavier tires and wheels
• Lower mount type: E3(100X128X10)
• Upper mount type: 10X1.25
• Compressed length: 13.26 in; extended length: 17.71 in; stroke length: 4.45 in

Product Details

KYB Gas-a-just struts are engineered around a monotube layout with separate gas and oil chambers. That design supports consistent damping and immediate response when suspension demand increases, while maintaining a controlled ride during normal driving. For GM full-size platforms, this part is aimed at restoring the handling balance expected from the original suspension design.

This part cross-references Monroe Shocks & Struts (e.g., 39105) for the same application. Part number 551121 is also listed with General Motors interchange references for select OE replacement use.

What This Strut Helps Address

• Excessive front-end bounce or oscillation
• Loose steering response after strut wear
• Reduced control when towing or carrying heavier loads
• Ride fade from aging hydraulic components
• Noise or vibration related to worn suspension damping

Installation Notes

Install on the front position only for the listed applications. KYB recommends replacing the strut mount with part number SM5530 to reduce noise and vibration, and using strut boot SB129 to help protect the new strut from dirt, debris, and road salt. Verify vehicle equipment before ordering, since several fitments exclude electronic suspension, ZW7 Premium Smooth Ride Suspension, adjustable suspension, or police package configurations.

Fits 2008-2014 Cadillac Escalade, front; Fits 2008-2014 Cadillac Escalade ESV, front; Fits 2008-2013 Cadillac Escalade EXT, front; Fits 2007-2014 Chevrolet Suburban 1500, front; Fits 2011-2014 Chevrolet Tahoe, front; Fits 2007-2014 Chevrolet Tahoe, front; Fits 2007-2013 Chevrolet Avalanche, front; Fits 2008-2013 Chevrolet Silverado 1500, front; Fits 2007-2013 Chevrolet Silverado 1500, front; Fits 2007-2014 GMC Yukon, front; Fits 2011-2014 GMC Yukon, front; Fits 2007-2014 GMC Yukon XL 1500, front; Fits 2007-2013 GMC Sierra 1500, front.

Quality Assurance

KYB is known for OE replacement suspension components, and the Gas-a-just line is built to match the needs of heavier-duty GM truck and SUV applications. The monotube construction, high-pressure gas charge, and chrome piston rod are used to support consistent operation and long service life in demanding front suspension use.