Firma 4000Kv Brushless Motor (SPMXSM1400)

Firma 4000Kv brushless motor is a high-performance powerplant designed for 1/10-scale RC cars, delivering crisp, responsive power on 2S LiPo packs for 4WD, 2WD, and on-road setups.

Built around a low-cog four-pole, eight-magnet rotor and housed in a CNC-machined aluminum shell, it uses insulated high-purity copper windings and a precise 3.175 mm (1/8") output shaft with robust bearings for durable, smooth rotation. Preinstalled 4 mm gold-plated bullet connectors simplify installation, and it’s designed to pair with the Firma 85A Smart ESC for efficient performance. It also serves as a straightforward upgrade for 540- and 550-size brushed motors that share the same diameter and mounting pattern, with pinions that have a 1/8" bore being compatible.