GPM Racing Aluminium 6061-T6 Rear L-Shape Piggy Back (Built-in Piston Spring) Adjustable Spring Dampers 139mm for Traxxas 1/7 Unlimited Desert Racer-85076-4 (UDR139R/LN)

Aluminium 6061-T6 Rear Piggy Back Dampers

This is an RC-scale rear suspension hop-up designed for the TRAXXAS UNLIMITED DESERT RACER PRO-SCALE 4X4 platform. The unit uses an L-shape piggy back design with a built-in piston spring to allow tuning of rebound force and improve pressure load response during high-speed off-road runs.

Key engineering points retained from the original design:

• Spring coil: Main spring wire increased from 1.8mm to 2mm for firmer spring rate while the original spring remains compatible if a softer feel is preferred.
• Damper shaft: Shaft diameter increased from 3.5mm to 5mm to reduce bending under load and improve durability for RC off-road stresses.
• Body and sealing: Aluminium 6061-T6 shock body with a shock-absorb cap to provide a tighter seal aimed at reducing oil leakage risk.
• Adjustability: Built-in piston spring plus adjustable top spring retainer and the red screw on the bottom of the negative-pressure oil cylinder allow rebound and preload tuning to suit differing track and terrain setups.

Installation and tuning role: these dampers replace the rear units on the specified TRAXXAS chassis, offering a stiffer shaft and thicker coils to change rebound character and load handling. Adjustment is performed mechanically at the spring retainer and by the lower red screw to affect negative pressure and rebound damping; verify fit at the rear damper area before run testing.

Packing includes

• Rear spring dampers – 2pcs

Original Name / Part No:

8460?8460X?8460R

Compatible Models

• TRAXXAS-1/7 UNLIMITED DESERT RACER PRO-SCALE 4X4-85076-4

Use these dampers when you need a firmer rear response and reduced shaft flex on the TRAXXAS UNLIMITED DESERT RACER PRO-SCALE 4X4; check seal torque and oil level after installation and adjust rebound incrementally to find the desired balance.

What are the primary durability improvements?

Increasing the damper shaft from 3.5mm to 5mm reduces bending under load and improves long term stiffness, while the thicker 2mm spring option raises the effective spring rate for harsher impacts.

How does the built-in piston spring alter tuning?

The internal piston spring provides an additional preload and a progressive damping element; combine it with top retainer adjustments and the lower red screw to tune negative pressure and rebound response precisely.

Are standard seals compatible with this body?

The 6061-T6 body is designed for improved sealing with the shock-absorb cap, but confirm seal dimensions and torque to achieve optimal leak resistance during high-speed operation.

What setup workflow do you recommend?

Start with stock preload and a medium shock oil, then incrementally increase preload or tighten the red screw to increase rebound damping while logging feel at each change for consistent setup decisions. Write Product Review Please sign in your account before you can write any review. Sign In Close

Made to order: GPM Racing parts are shipped to us from GPM’s factory, so please allow around 14 days for dispatch.