KellTrac Adjustable Front Drag Strut & Rear Shock Kit (KTI-FDS15RS) – 2015-2026 Mustang S550 & S650
Engineered for the serious racer and proven on both track and street, the KellTrac Adjustable Front Drag Strut and Rear Shock Kit delivers uncompromising traction, control, and performance for your 2015–2023 Mustang S550. This complete package combines KellTrac’s industry-first adjustable front drag struts with KellTrac Ultra Spec Viking Crusader rear shocks—a battle-tested pairing responsible for record-setting 60-foot times and consistent launches on nearly any surface.
This combination has been proven to achieve low 1.2-second 60-foot times on average prepped tracks and 1.3-second 60-foot times on basic asphalt surfaces—making it one of the most versatile and effective drag suspension setups available for the S550 platform.
Complete Front & Rear Solution for Maximum Traction
KellTrac took the guesswork out of suspension tuning by pairing their proprietary front struts with Viking Crusader rear shocks, giving you a fully matched system optimized for drag racing performance and repeatability. Whether you’re running naturally aspirated, nitrous, or boosted, this kit provides the adjustability and control to dial in your Mustang for consistent, confident launches every time.
Front Adjustable Drag Struts
After over a year of development and testing, KellTrac’s S550 Adjustable Drag Struts were designed to be the ultimate single-adjustable solution for serious racers. Developed in partnership with one of the world’s leading shock manufacturers, these struts feature exclusive drag race-specific compression and rebound valving for precise tuning on any surface.
- Direct OEM replacement designed for street/strip use
- Increased extension travel over stock struts for improved weight transfer
- Single adjustable valving for fine-tuning power levels and surface grip
- Retains factory sway bar (if desired)
- Compatible with OEM or aftermarket upper mounts and springs
- High-strength steel construction with corrosion-resistant coating
- Zero increase in NVH (Noise, Vibration, Harshness)
Front Strut Benefits
- Promotes improved traction and controlled weight transfer
- Allows higher power application due to increased suspension travel
- Prevents excessive wheelies and reduces wheel hop
- Improves stability, launch control, and handling response
- Retains stock-style springs for easy installation
Rear KellTrac Ultra Spec Viking Crusader Shocks
The KellTrac Ultra Spec Viking Crusader Rear Shocks are a purpose-built evolution of the Viking Double Adjustable design, featuring exclusive KellTrac valving for a broader range of applications and ultimate launch control. These shocks use a spherical bearing lower axle mount for faster reaction time on launch and superior suspension articulation under power.
- Double-adjustable design for independent rebound and compression tuning
- KellTrac-exclusive valving for superior drag race performance
- Spherical bearing lower mounts for faster response and improved traction
- Ideal for street/strip and dedicated drag setups
- May introduce minor NVH (not for show-only builds)
- Recommended with aftermarket upper shock mounts for best performance
Rear Shock Benefits
- Maximizes rear tire grip during launch
- Improves 60-foot consistency
- Allows precise damping adjustment for track and street conditions
- Proven performance for 7–12 second cars
Proven Performance – Track & Street
From record-breaking heads-up racecars to daily-driven street builds, this KellTrac suspension setup delivers unmatched performance. The balance of extension, rebound, and compression control allows for consistent launches and stability, regardless of surface or power level.
Spring Rate Recommendations
- NA / Nitrous: 150 lb/in Front – 800 lb/in Rear (BMR or Steeda Drag Springs)
- Boosted Applications: 170 lb/in Front – 800 lb/in Rear (BMR Min Drop Springs)
- 1000+ WHP Boosted: 170 lb/in Front – 980 lb/in Rear (BMR Min Drop Front / Handling Rear)
Included Support
All KellTrac Spec Shock and Strut purchases include limited remote technical support to help you fine-tune your setup for your power level and surface conditions.
Why Choose KellTrac?
Built by racers, for racers—KellTrac’s engineering focus is on real-world performance and results. Each product is tested extensively in competition environments to ensure durability, consistency, and confidence where it counts most. If you’re serious about making your Mustang launch harder, go faster, and stay consistent, the KellTrac Adjustable Front Drag Strut & Rear Shock Kit is the proven choice.
Fitment
- 2015 Ford Mustang S550
- 2016 Ford Mustang S550
- 2017 Ford Mustang S550
- 2018 Ford Mustang S550
- 2019 Ford Mustang S550
- 2020 Ford Mustang S550
- 2021 Ford Mustang S550
- 2022 Ford Mustang S550
- 2023 Ford Mustang S550
- 2024 Ford Mustang S650
- 2025 Ford Mustang S650
- 2026 Ford Mustang S650
Compatible with GT, GT350, GT500, and EcoBoost models. Designed specifically for drag race and street/strip applications.
Kelltrac Terms Of Service
Kelly considers his Kelltrac line to be a specialty line for a unique customer base and has his own terms of service in addition to Beefcake Racing's. You must accept these terms on all Kelltrac orders. Please read shipping times, cancellation, and returns. If time is of the essence, we do have other options that can ship right away / quicker. Just reach out to one of our sales associates at Beefcake Racing.
Cancellations & Returns
KellTrac Innovations does not accept product returns. Once your order ships, you own it and we will not accept it back - NO EXCEPTIONS. We do not accept order cancellations after the product has shipped. If you understand and accept this please check the box and continue checking out. If you do not accept this, please stop and discontinue the order process. Thanks!
Due to the custom nature of our business and product offerings, we charge a 20% order cancellation fee, period, non-negotiable, no matter who you are. Orders can only be cancelled before the product ships. We do not accept order cancellations after the product has shipped. If you understand and accept this please check the box and continue checking out. If you do not accept this, please stop and discontinue the order process. Thanks!
Leadtime
Please be aware that most orders ship within 2-4 weeks. In some (rare) cases, orders can take up to 6-8 weeks to ship. Holidays can severely impact these lead times. *DO NOT CONTACT US ABOUT YOUR ORDER UNLESS IT IS OLDER THAN 20 BUSINESS DAYS!* If you understand and accept this please check the box and continue checking out. If you do not accept this, please stop and discontinue the order process. Thanks!
CA Residents: WARNING: Cancer and Reproductive Harm www.P65Warnings.ca.gov
