BDS 4-Inch Radius Arm Lift Kit | FOX 2.5 Performance Elite | Ram 2500 4WD Diesel 2019–2026 | SKU: 1660FPE

The BDS 1660FPE is a 4-inch radius arm front lift kit with FOX 2.5 Performance Elite external reservoir shocks for the 2019–2026 Ram 2500 4WD diesel — the DT-generation platform. Heavy-duty BDS radius arms replace the factory arms, correcting caster at lift height and reducing bushing bind. Diesel-tuned front coil springs deliver 4 inches of lift at the correct spring rate for the diesel engine weight. FOX 2.5 PE external reservoir shocks deliver advanced valving and heat-managed damping for sustained off-road and towing performance at lifted height.

This kit has three hard fitment splits before it applies to your truck.

First — engine: diesel-tuned coil springs. Ram 2500 gas requires a different kit — gas and diesel springs are not interchangeable. Order 1699FPE for the 2019–2026 Ram 2500 4WD gas.

Second — generation: the 2019–2026 Ram 2500 is the DT platform. The 2018 and earlier Ram 2500 is the DS platform — order 1762FPE for the 2014–2018 Ram 2500 4WD diesel.

Third — drivetrain: 4WD only. Ram 2500 2WD is not compatible.

If you want FOX 2.0 Performance Series shocks at a lower price point on the same platform, order 1660FS — the radius arm system and spring package are identical.

Component Specifications

What Is and Is NOT Included

Critical Compatibility

Three fitment confirmations required before ordering.

Want FOX 2.0 instead of FOX 2.5 PE? Order 1660FS.
Not sure which Ram 2500 platform you have? Text (469) 407-7538 before ordering.

FOX 2.5 PE vs. FOX 2.0 — Which Shock Do You Need?

2019–2026 Ram 2500 Diesel 4-Inch Lift Kit Variant Reference

Installation Notes

Professional installation is required. The radius arm lift on a diesel platform requires a qualified suspension shop with experience on heavy-duty truck platforms. Do not attempt DIY installation.

Full front-end alignment is mandatory after installation. Do not drive on public roads before alignment is completed. Running a lifted diesel truck without post-installation alignment causes accelerated tire wear, steering pull, and handling instability under tow.

Driveline inspection is required after installation. Inspect driveshaft angles and U-joint operating angles after installation. Confirm angles are within acceptable operating range before towing — driveline issues under load on a diesel platform are costly to address after the fact.

External reservoir routing. Follow BDS and FOX installation instructions for reservoir placement. Avoid pinch points, heat sources, and moving components during routing. Improper reservoir placement can damage the reservoir line and void the FOX warranty.

Torque all fasteners to BDS specification. Torque specs are included in the BDS installation instructions. Do not estimate torque values on a diesel-weight platform.

FOX shock break-in period. Allow FOX 2.5 PE shocks to complete the manufacturer-recommended break-in period before aggressive off-road or heavy towing use.

Text (469) 407-7538 to confirm engine, platform, and drivetrain before ordering.

The Obsidian Take

The BDS 1660FPE is the correct kit for the 2019–2026 Ram 2500 4WD diesel owner who wants 4 inches of front lift with corrected radius arm geometry and maximum shock performance. The FOX 2.5 PE external reservoir is the reason to choose this kit over 1660FS — the reservoir separates the oil from the nitrogen gas charge, managing heat under sustained off-road terrain and heavy diesel towing loads so damping performance stays consistent where a standard shock body begins to fade. On a diesel platform that regularly sees trailer weight, the difference between a 2.0 and a 2.5 PE shows up exactly when it matters.

If your use case is primarily daily driving and moderate weekend use, FOX 2.0 (1660FS) delivers meaningfully better damping than factory at a lower price point — the external reservoir is more capability than that use case requires.

If your Ram 2500 is gas, diesel-tuned springs are not the correct rate for the lighter gas engine weight — order 1699FPE. If it is a 2018 or earlier DS platform, the DT kit geometry does not apply — order 1762FPE for the correct platform. If it is a Ram 3500, this kit does not apply.

DT platform, diesel, 4WD, 4 inches, FOX 2.5 PE — the 1660FPE is the complete, correctly-tuned front-end solution for the Ram 2500 diesel owner who tows hard and wants the damping performance to match.

Common Questions

What is the difference between 1660FPE and 1660FS?
Both kits fit the 2019–2026 Ram 2500 4WD diesel and deliver 4 inches of front lift with the same BDS radius arms, diesel-tuned springs, and track bar correction bracket. The only difference is the shock — 1660FPE uses FOX 2.5 Performance Elite with external reservoir and advanced valving. 1660FS uses FOX 2.0 Performance Series without external reservoir at a lower price point. For sustained towing and aggressive off-road use, the 2.5 PE is the correct specification. For daily and moderate use, FOX 2.0 covers the application at lower cost.

Why can't I use gas springs on my diesel Ram 2500?
The diesel engine is significantly heavier than the gas engine on the Ram 2500 platform. Front coil springs are tuned for a specific front axle weight — gas-tuned springs under a diesel engine will sag, drop ride height, and compromise front-end geometry under load. Order 1660FS or 1660FPE for the diesel platform. Order 1699FS or 1699FPE for the gas platform.

Does this kit lift the rear of the truck?
This kit addresses front lift via the radius arm upgrade. Rear lift components are not included. Confirm rear lift requirements with your installer before ordering if needed.

Is this a DIY install?
No. The radius arm lift on a diesel platform requires a qualified suspension shop. This is not a leveling kit — professional installation is required.

What warranty does this kit carry?
BDS suspension components carry the BDS No-Fine-Print Warranty. FOX 2.5 PE shocks carry a FOX 1-year limited warranty.

Verified Fitment