Product Details

The Riaction GT1 Coilovers for the 2017+ Audi S4 B9 deliver a premium, adjustable suspension upgrade built for drivers who want more from their S4 B9 than the factory setup can offer. These Audi S4 coilovers are engineered to pair street comfort with canyon and track capability, giving you the stance, handling, and adjustability you've been chasing without compromising daily driveability. Whether you track your B9 S4 on weekends or log daily miles, this B9 coilover kit dials in ride height and damping to match how you actually use the car.

Every GT1 set features a monotube damper with 32 levels of damping adjustment, so you can tune ride quality to match the road, the weather, or your driving mood. Full-length ride-height adjustment separates preload from ride height — meaning you can drop the S4 B9 to the height you want while preserving spring travel and shock stroke. Riaction coilovers for the 2017+ Audi S4 are fully rebuildable and backed by a 2-year warranty, making the GT1 a long-term suspension investment rather than a disposable upgrade.

GT1 Series Technology

  • Monotube linear damper with seamless 52mm electroplated carbon steel body
  • 32-level damping adjustment (1-Way)
  • 44mm CNC-machined 6061 aluminum high-flow piston
  • 20mm piston rod for MacPherson applications / 14mm for non-MacPherson
  • SAE9254 cold-wound linear main springs
  • Multi-thickness valving shims for consistent damping
  • Polyurethane oil seals and 7.5W suspension fluid
  • Low-gas-pressure design for improved compliance
  • Fully rebuildable — built to be serviced, not replaced

Features

  • Full-length ride-height adjustment (preload-independent)
  • 32 levels of damping adjustment
  • Optional Swift Springs upgrade (sold separately)
  • 2-year limited warranty
Specifications
Part Number AD-009-SS
Part Name Riaction GT1 Coilovers
Vehicle 2017+ Audi S4
Chassis Code B9
Adjustment Type 1-Way
Ride-Height Adjustable Yes
Spring Rate - Front 10 Kg/mm
Spring Rate - Rear 8 Kg/mm
Top Mounts - Front OEM
Top Mounts - Rear OEM
Camber Plates - Front No
Camber Plates - Rear No
Suspension Design - Front True Coilover
Suspension Design - Rear Divorced
Notes 48.5mm

Vehicle fitment

This product fits the vehicles listed below.

YearMakeModelNotes
2017AudiA448.5mm
2017AudiS448.5mm
2018AudiA448.5mm
2018AudiS448.5mm
2019AudiA448.5mm
2019AudiS448.5mm
2020AudiA448.5mm
2020AudiS448.5mm
2021AudiA448.5mm
2021AudiS448.5mm
2022AudiA448.5mm
2022AudiS448.5mm
2023AudiA448.5mm
2023AudiS448.5mm
2024AudiA448.5mm
2024AudiS448.5mm
2025AudiA448.5mm
2025AudiS448.5mm
2026AudiA448.5mm
2026AudiS448.5mm

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