HPI Baja Rear Upper Arm Alloy with Nylon Ball Ends by GPM BJ057  [BJ057]

Rear upper arm for HPI Baja

This is an RC-scale rear upper arm produced by GPM for use on HPI Baja platforms, constructed from alloy with nylon black ball ends as specified in the part name. The component serves as a replacement or upgrade within the rear suspension linkage, preserving mounting points and ball end interfaces typical to Baja setups.

The arm's alloy body provides structural rigidity for link geometry, while the nylon ball ends offer wear resistance and reduced noise at pivot points. Installation requires basic disassembly of the rear suspension linkage, transfer of existing hardware where applicable, and verification of clearance with the shock towers and rear hubs. Check thread engagement on any retaining screws and confirm that ball end rotation is free yet secure.

For setup and tuning, the part functions as a direct replacement in the upper rear linkage; it can affect toe and camber behavior only through its geometry and mounting position, so recheck alignment after fitment. Routine maintenance recommended includes inspection for play at the ball ends and lubrication or replacement if excessive wear appears.

Use this GPM BJ057 rear upper arm where like‑for‑like replacement or matched alloy linkage is desired on HPI Baja models, and verify fitment and suspension alignment after installation.