KYB SB121 Suspension Strut Bellows - Front

KYB Boot Kit for Audi Front Struts

The KYB SB121 boot kit is built to protect front struts from dirt, dust, sand, salt, and other road debris that can wear on the shaft, upper seal, and bushing. It also includes a poly foam bumper to help prevent bottoming out and reduce damage from extreme suspension movement.

Part of KYB’s Boot Kits line, this suspension strut bellows is made to match OE-style fit and function for Audi applications. If you need a KYB SB121 strut boot kit for an Audi S5, RS5, or 90 Quattro front suspension, this part is built for that job.

Key Features

• Superior-quality boot helps protect the strut shaft from leak-causing dirt and debris
• Poly foam bumper helps prevent the strut from bottoming out
• Built to match or exceed OE design and quality
• Protects the upper seal and bushing from contamination
• Designed and built specifically for Audi vehicles

Detailed Product Overview

The KYB SB121 is a suspension strut bellows that covers the full strut shaft with a durable plastic boot, helping keep abrasive contaminants away from critical suspension components. By shielding the polished shaft and sealing surfaces, it supports longer service life for the strut assembly. This part cross-references Monroe Shocks & Struts 63619 for the same application.

Compatible With front applications on 2008-2017 Audi S5, 2013-2015 Audi RS5, and 1990-1992 Audi 90 Quattro. For shoppers searching for an Audi front strut boot kit, Audi S5 suspension bellows, or KYB SB121 replacement boot, this part matches those vehicle-specific needs.

What It Helps Address

• Road grit reaching the strut shaft and seal area
• Wear on the upper seal caused by contamination
• Bushing damage from dirt and abrasive debris
• Strut bottoming out during extreme suspension travel
• Damage to nearby suspension components from harsh movement

Installation Notes and Tips

Install the boot on the front strut assembly during strut service or replacement. Inspect the shaft, seal area, and bushing before reassembly, and confirm the bumper seats correctly within the boot assembly. Verify front fitment by model year before ordering the KYB SB121.

Quality Assurance

KYB Boot Kits are engineered to OE-style standards for fit and function, with construction intended to meet or exceed original equipment design expectations. The KYB SB121 is built specifically for Audi front suspension applications.