TRAXXAS UNLIMITED DESERT RACER PRO-SCALE 4X4 Rear L-shape Piggy Back Shock Upgrade UDR139R/LN by GPM  [UDR139R/LN]

6061-T6 Rear Piggy Back Shock Upgrade

This rear damping upgrade is made for the TRAXXAS UNLIMITED DESERT RACER PRO-SCALE 4X4 and employs an L-shape piggy back with an internal piston spring to let you tune rebound behaviour and withstand high-speed off-road loads.

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: Aluminum 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: the dampers replace the stock rear units and provide a stiffer shaft and thicker coil option to alter damping feel and load handling. Use mechanical adjustments at the top retainer and the lower red screw to dial in negative pressure and rebound; always confirm fitment at the rear damper mounts prior to running.

Use these when you want firmer rear support and reduced shaft flex on the TRAXXAS UNLIMITED DESERT RACER PRO-SCALE 4X4; verify seal condition and recheck oil after a break-in run, then fine-tune rebound in small steps.