Spektrum SPMXSM1700 Firma 4074 2050Kv Motor

The Spektrum Firma 4074 2050Kv is a four-pole sensorless brushless motor built for 1/7 and 1/8 scale buggies, truggies, and monster trucks running 3S to 6S LiPo setups. It is the motor included with the Firma 150 Amp ESC/motor combo (SPMXSEMC05), making it a direct replacement for that system as well as a strong upgrade path for large-scale bashers and racers moving up in power.

The low-cog 4-pole, 8-magnet rotor design delivers smooth power delivery and precise throttle control even at low speeds, with the strong bottom-end torque that four-pole motors are known for. Construction is high quality throughout: a CNC-machined aluminum housing for heat dissipation, insulated high-purity copper windings for efficiency, precision ball bearings, and a hardened alloy steel output shaft.

The Safe-D shaft is a standout feature — it provides a C-clip locking point that mechanically prevents pinion gear slip under rapid acceleration and hard braking. Factory-installed 4mm gold-plated bullet connectors make installation plug-and-play, and the motor is perfectly matched to the Firma 150 Smart ESC.

Dealer fitment references include the ARRMA 6S BLX family: Kraton 6S, Big Rock 6S, Felony, Mojave 6S, Fireteam, Notorious, Infraction V2, and Typhon 6S. The package includes one brushless motor.