HPI Baja Front Lower Arm CNC-Grade Alloy BJ055 by GPM  [BJ055]

GPM Alloy Front Lower Arm Technical Overview

The GPM BJ055 front lower arm is a machined alloy replacement engineered for HPI Baja chassis. It is manufactured to serve as a direct swap for worn plastic arms and is designed to align precisely with the original suspension mounting points on the HPI Baja platform.

In operation the lower arm defines hub location and affects roll centre and camber behaviour under load. Upgrading to the BJ055 increases local stiffness at pivot interfaces and provides a stable mating surface for ball studs and link brackets, which assists precise tuning of suspension response and component longevity in demanding off-road conditions.

Installation requires basic chassis disassembly: remove wheel and hub assembly, unfasten the old lower arm hardware, transfer or renew linkage and pivot components as necessary, locate the GPM arm into the stock mounts, and verify articulation and geometry before field use. After assembly, sweep steering and suspension through full travel to confirm no binding and correct alignment.

For serious hobbyists and tuners seeking a precision alloy arm that preserves factory geometry while raising pivot rigidity, the GPM BJ055 is a robust, performance-oriented upgrade.