Associated RC18T Precision Ball Differential AR100S by GPM  [AR100S]

Engineering note - compact ball differential

The AR100S is a CNC-friendly replacement-style ball differential intended for the Associated RC18T and compatible Latrax platforms. The component set combines steel load-bearing parts with aluminium rotating elements to manage inertia while maintaining structural strength for model-scale drivetrains.

Internal construction uses precision balls with matching thrust washers to generate predictable torque transfer characteristics. Low-friction components include a Delrin pulley and aluminium output cups, while sealed ball bearings are positioned at primary rotational interfaces to minimise parasitic drag.

Preload is regulated using the central adjustment screw: incremental tightening compresses the ball stack to increase resistance to differential action, while controlled loosening reduces resistance to allow freer wheel speed differentiation. This approach provides repeatable on-vehicle setup changes without specialised tooling.

For technical builders and shop tuners working on the listed chassis, the AR100S supplies a straightforward preload-based method to alter handling characteristics while preserving routine service access.