Upgrade your Defender HD11 with a control arm built for real-world abuse—designed, engineered, and manufactured in the USA by Thumper Fab. Our Forward Control Arms deliver the strength you need, without the unnecessary weight that kills ride quality.

Engineered Strength Without the Weight

Why run a boxed A-arm design? Because strength matters—but how you achieve it matters even more.
Thumper Fab’s boxed control arms feature a precision-engineered internal skeleton that reinforces high-stress zones while eliminating excess material where it isn’t needed. The result:

• Increased torsional strength for superior durability
• Reduced unsprung weight compared to traditional bulky designs
• Improved suspension performance and ride quality

This isn’t just heavier steel—it’s smarter engineering.

Flexible Setup: Ball Joint or Uniball

Our patented design gives you options based on how you ride:

•    Ball Joint Configuration
Ideal for everyday driving, trail riding, and general use while maintaining OEM-style function.
•    Uniball Upgrade Option
Step up to a high-performance uniball bearing for extreme strength and articulation. Commonly used in racing and harsh off-road environments, this setup is built to handle serious abuse.

Installation Options Built Around You

We’ve made install as simple—or as customizable—as you want it:
✅ Pre-Installed Bushings & Ball Joints (Recommended)

Skip the headache and let us handle it.

• Professionally pressed using precision equipment
• Ensures proper fitment and maximum lifespan
• Eliminates risk of damage from improper installation

⚠️ Important: OEM bushings are notoriously difficult to remove and reinstall without the correct tools. We highly recommend selecting this option to save time, frustration, and potential damage.

🔧 Reuse Your OEM Hardware

Running a newer machine? You can reuse your factory components.

• Compatible with OEM bushings and ball joints
• Cost-effective option if your hardware is in great shape

Note: Professional installation and proper press tools are strongly recommended to prevent damage during removal and install.

Built for the Demands of Real Riders

Whether you're working your Defender, hitting tough trails, or pushing limits on the weekend, these forward control arms are designed to keep up—and outlast.

•    Precision laser-cut and welded construction
•    Optimized for durability and performance
•    Designed for proper geometry and fitment

Installation & Tire Size Notes:
We have tested fitment with multiple tire sizes up to a 37” tire. Varying tire sizes from manufacturers may require the use of a wheel spacer or larger offset wheel for proper clearance.