Bilstein 5100 Lower Spring Adapters for 2.5” ID Race Springs

Upgrade your Titan-swapped suspension without the cost of a full coilover conversion. 

Bilstein 5100s for a Titan-swap are popular because they’re cheap, durable, and ride well. But they’re stuck with the stock 460 lb/in Titan coils. Those are soft once you add armor, winches, or gear. You can’t just swap in standard 2.5" ID race springs like Eibach or Hyperco because the 5100’s lower spring perch is shaped for the big OEM coil.

The CJD Racing Bilstein 5100 Lower Spring Adapters allow Bilstein 5100 front struts to accept standard 2.5” ID x 12” race springs from manufacturers such as Eibach, Hyperco, and other popular racing spring brands. Designed specifically for Titan-swapped Nissan Frontiers, Xterras, Titans, and Armadas running Bilstein 5100 struts, these billet adapters replace the factory lower spring retainer with a precision-machined flat spring seat.

The factory Bilstein 5100 lower perch is designed only for the large OEM Titan coil spring, limiting suspension tuning to the stock spring rate. With the CJD Racing adapter installed, you can choose the spring rate that matches your vehicle’s weight and intended use, providing improved ride quality, better handling, and increased support for aftermarket accessories.

Whether you’re running a lightweight trail truck or a fully armored overland build with bumpers, winch, skids, and camping gear, these adapters let you dial in the suspension to fit your setup.

Features

• Precision CNC-machined billet construction
• Converts Bilstein 5100 struts to accept 2.5” ID x 12” race springs
• Compatible with Eibach, Hyperco, and similar flat-end race springs
• Direct replacement for the factory lower spring retainer
• Properly centers the spring to prevent movement or binding
• Allows spring rate tuning without purchasing expensive coilovers

Benefits

• Improve ride quality by selecting the correct spring rate
• Better support for added vehicle weight
• Fine-tune ride height using spring selection instead of excessive preload
• More suspension tuning options while retaining the reliability of the Bilstein 5100

Typical Spring Rate Recommendations

• 500 lb/in – Lightly equipped vehicles
• 550–600 lb/in – Most Titan-swapped Frontiers and Xterras
• 650 lb/in – Heavy armor, winch, roof rack, overland equipment, or constant cargo loads

Vehicle Fitment

• Nissan Frontier Titan Swap
• Nissan Xterra Titan Swap
• Nissan Titan equipped with Bilstein 5100 front struts
• Nissan Armada equipped with Bilstein 5100 front struts

Notes

• Designed for use with 2.5” ID x 12” flat-end race springs.
• Professional installation is recommended.
• Always verify spring rate and travel for your specific suspension setup to prevent coil bind or improper suspension performance.