TRX-4 Front Brass Knuckle Arms for Trail Crawling TRX4021BX by GPM  [TRX4021BX]

Heavy brass inner knuckles for TRX-4 trail performance

This set replaces the stock inner front knuckle components on TRX-4 scale crawlers with brass arms that deliver consistent fit and added mass. Precision machining ensures the knuckle pivot stays free while the extra weight helps the vehicle settle into technical moves. These parts are intended for RC models only and must not be used on real vehicles.

Fitting tips: the brass inner knuckle locates into the knuckle inner case and is secured with the included stainless steel fasteners. Confirm bearing clearance and alignment during assembly, and use a moderate threadlocker on the button head screws to guard against vibration-related loosening. No specialised tools are necessary beyond standard hex drivers for the specified screws.

Included hardware and parts: inner part front knuckle 2pcs, stainless steel round head screw 3x16 2pcs, stainless steel round head screw 2.5x3 6pcs, stainless steel button head screw 2.5x8 4pcs. Each brass arm yields about 50g of added external weight, giving you a straightforward method to bias the front end for better traction on climbs.

If you want a durable inner knuckle swap that increases front ballast without changing mount points, this brass kit is a direct-fit option that alters traction and steering characteristics.