Steeda S550 Ford Mustang Ultimate IRS “Stop The Hop” Pack

Steeda S550 Mustang Ultimate IRS "Stop The Hop" Pack

The Steeda Ultimate Stop The Hop package reduces rear-wheel hop during acceleration. It is aimed particularly at forced-induction and drag-focused S550 Mustangs where putting power down is the priority.

Package contents

• Both versions contain IRS subframe bushing supports 555-4437, subframe alignment kit 555-4438, billet aluminium vertical links 555-4121 and adjustable rear toe links 555-4120.
• Coupe kit 555-2129 also includes chrome-moly subframe braces 555-5754.
• Convertible kit 555-2129-VERT omits these braces because the convertible has a factory rear brace.

The supports limit subframe deflection, the alignment sleeves centre it in the chassis and the stronger vertical links reduce movement associated with stock rubber bushings. Toe can be adjusted with the links installed. Coupe braces connect three chassis/subframe mounting points. Steeda states that the package does not increase noise or vibration.

Instructions and videos

• Product video on YouTube 1
• Product video on YouTube 2

Related vehicles

• 2015–2023 Mustang S550 GT and EcoBoost, selecting coupe or convertible

Not for Mach 1, GT350 or GT500: Mach 1/GT350 do not require the included bushing supports, while GT500 needs different vertical links.