Brock’s Performance FXR Swingarm

Built for riders pushing the limits of the FXR platform, the Brock’s Performance FXR Swingarm is a race-proven, street-capable solution engineered to handle extreme horsepower, high torque, and aggressive riding without flex, axle movement, or instability.

Designed, machined, and assembled in the USA by Brock’s Performance, this swingarm brings over 25 years of drag-racing technology into a V-Twin chassis that demands strength, adjustability, and precision.

🏁 Why Choose the Brock’s Performance FXR Swingarm?

• Built to control high-power, high-torque FXR builds

• Adjustable wheelbase for improved traction and stability

• Lighter and stronger than OEM

• Designed to accept wider rear tires

• Race-proven design adapted for long-term street use

This is the swingarm for turbo, big-inch, and performance-driven FXRs where OEM parts simply aren’t enough.

🔧 Construction & Materials

• Handcrafted 6061-T6 aluminum swingarm

• Proprietary custom aluminum extrusion (exclusive to Brock’s Performance)

• Black powder-coated finish

• Billet aluminum ends with reinforced bracing

• Designed for FXR models with 4.5″ transmission housing

• Designed, machined, and assembled in the USA

⚙️ Adjustability & Performance

• Adjustable wheelbase: stock position up to +3″ extended

  • Extended wheelbase improves straight-line stability and traction

• 3-position shock mounts (1/2-13 thread):

  • Stock height

  • –1″

  • –2″

• Adjustable brake bar included for undermount aftermarket brake calipers

💡 That extra 3″ of wheelbase can be worth up to 0.3 seconds in the ¼-mile.

🛠 Included Hardware & Components

• Centerless-ground 4130 Chromoly axle
  (Choose from 3/4″, 25mm, 1″, or 28mm)

• Reversible billet aluminum axle adjusters

• PTFE-lined spherical bearings (preinstalled) from Worldwide Bearings

• Pivot bushings to use OEM pivot shaft
  (Choose 5/8″ or 3/4″ bushing sets)

• Adjustable brake bar with mounting hardware

• Stainless hardware where applicable

📐 Dimensions & Weight

• Interior swingarm width at axle: 10.25″

• Total installed weight (with 3/4″ axle & bushings):
  14.32 lb (6.50 kg) — over 50% lighter than OEM

Weight Breakdown

• Swingarm w/ bearings: 10.70 lb

• Axle (varies by size): 2.80–3.40 lb

• Pivot bushings: 0.43–0.50 lb

• Brake bar & hardware: 0.39 lb

🔩 Fitment

• Harley-Davidson FXR models (1982–2000)

• Designed for high-power street and drag applications

• ❌ Not designed for off-road use

⚠️ Critical Installation Notes

This is NOT a 100% bolt-on swingarm.

Installation may require:

• Offset sprocket or pulley

• Wheel and/or shock spacers

• Aftermarket rear brake setup (OEM rear brake will NOT fit)

• Modification of rear wheel carrier (especially with wide tires)

• Possible transmission case modification when using 3/4″ pivot shaft on high-power builds

📌 Overall rear hub width is critical:
10.250″ +0.020″ / –0.000″ (260.35mm +0.50mm / –0.00mm)
Improper spacing can affect handling, safety, and warranty coverage.

🧠 Warranty & Fitment Disclaimer

Due to variations in FXR frames, accessories, and prior modifications, fitment cannot be guaranteed on every build.

• Unmodified swingarms in resalable condition may be returned with an RMA

• Customer is responsible for shipping costs

• Refunds issued after inspection by Brock’s Performance

🏍 Who This Swingarm Is For

✔ High-horsepower FXRs
✔ Turbo or big-inch builds
✔ Drag racing & performance street riding
✔ Riders who want stability, traction, and strength

❌ Not intended for casual bolt-on installs
❌ Not for off-road use