Parts/Electric power/Brushless motors/Spektrum RC Firma 4-Pole Brushless Motor (3900Kv)
Spektrum RC Firma 4-Pole Brushless Motor (3900Kv)
Spektrum RC

Spektrum RC Firma 4-Pole Brushless Motor (3900Kv)

Part # SPMXSM3300
Where to buy
$59.99
AMain Hobbies
Seen Oct 12, 2026
$59.99Buy
Prices are as last seen at the store; stock is not tracked.

About this part

The Spektrum RC Firma 4-pole Brushless Motor, is a great choice for 1/10 Scale 4WD models looking for a high RPM motor upgrade running up to 3S (12.6v) power. Featuring a low cog 4-pole rotor design, CNC machined aluminum housing, insulated high purity copper windings, high-quality alloy steel 5mm output shaft and high-precision bearings for high durability and smooth rotation. Preinstalled 4mm bullet connectors are used for ease of use and instillation. 

NOTE: Only compatible with the 85A Firma ESC (sold separately) when run on 2S power.

Features: 
  • Perfect upgrade for 540 and 550 size brushed motors with the same shaft diameter and mounting pattern 
  • Perfectly matched for the Firma 130 Smart ESC (sold separately)
  • High-quality 4-pole sintered rotors
  • Includes 4mm gold plated bullet connectors
  • Precision ball bearings and hardened steel 5mm shaft
  • SafeD-5 Pinion compatible
Specifications:
Application: 1/10 Scale Surface
Input Voltage: 12.6V
RPM/Volt (Kv): 3900Kv
Maximum Continuous Current: 45A
Motor Type: Brushless
Outer Diameter: 1.4" (36 mm)
Product Length: 2.35" (60 mm)
Shaft Diameter: 0.2" (5 mm)

Includes: 
  • (1) Spektrum Firma 3900kv Sensorless Brushless Motor
  • (1) Product Manual
CA Residents Prop 65 Warning WARNING: This product can expose you to chemicals including Di(2-ethylhexyl)phthalate (DEHP), which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov Details...

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