Overview
The SPM Firma 3650-3400Kv 4-Pole Sensorless Brushless Motor is a high-performance electric motor designed for RC enthusiasts looking to upgrade their vehicles with reliable, efficient brushless power. This 5mm shaft motor represents the pinnacle of Spektrum's Firma range, engineered to deliver consistent performance across a wide variety of RC applications. Whether you're running a competitive RC car in the UK or simply seeking a dependable motor upgrade, the 3650-3400Kv specification offers the perfect balance between torque and speed, making it an excellent choice for anyone serious about their RC hobby.
Brushless motors have become the gold standard in modern RC racing and bashing, and this Firma model exemplifies why. With its sensorless design, this motor requires no additional sensor wires or complex calibration procedures, making it straightforward to install and use across different ESC platforms. The 4-pole configuration ensures smooth, reliable power delivery with minimal vibration, whilst the 3400Kv rating positions this motor as an ideal choice for a wide range of vehicle types. From track racing to off-road bashing, a brushless RC motor of this quality will transform your driving experience.
RC Model Shop stocks this Firma motor as part of our comprehensive range of Spektrum brushless components. As an authorised Spektrum dealer, we understand the demands of UK RC hobbyists and provide only genuine, quality-assured products that deliver performance you can trust. The 3650-3400Kv motor's versatility and proven track record make it a popular choice amongst experienced RC enthusiasts throughout the United Kingdom.
Key Features
- 4-Pole Brushless Design — The 4-pole configuration provides superior efficiency compared to older brushed motors, delivering more power output whilst consuming less energy from your battery, resulting in longer run times and less heat generation during extended driving sessions.
- 3400Kv Rating — This Kv specification determines the motor's speed characteristics; a 3400Kv motor delivers excellent mid-range performance suitable for versatile driving applications, offering the ideal compromise between acceleration and top speed for most RC vehicle types.
- Sensorless Operation — Without the need for motor sensors, this motor simplifies installation and reduces overall system complexity, making it compatible with a wider range of ESC options and eliminating potential sensor failure points that can plague sensored motors.
- 5mm Shaft — The 5mm diameter shaft is a standard specification in modern RC motors, ensuring compatibility with the vast majority of pinions and gearboxes available on the UK market, making replacement and upgrades straightforward and hassle-free.
- 3650 Size Format — This standard motor size (36mm diameter, 50mm length) is widely recognised across the RC industry and fits in most competitive and recreational RC vehicles, from touring cars to drift machines and beyond.
- Reliable Spektrum Engineering — Built by Spektrum, a brand synonymous with quality and performance in the RC world, this motor benefits from rigorous testing and quality control standards ensuring consistent performance and durability across every unit produced.
Technical Performance
The SPM Firma 3650-3400Kv motor represents serious engineering excellence designed for demanding RC applications. Constructed with precision-wound stator windings and high-quality rotor assembly, this brushless motor delivers consistent, reliable performance session after session. The 4-pole construction ensures smooth commutation and minimal cogging, translating to responsive throttle input and smooth acceleration curves that competitive drivers demand. The 3400Kv specification positions this motor in the sweet spot for general-purpose RC use; fast enough for exciting top speeds but not so extreme that battery drain becomes problematic. With its 5mm hardened steel shaft, this motor can handle the stresses of serious driving whilst maintaining precision alignment within your vehicle's drivetrain. The sensorless design eliminates complexity without sacrificing performance—this motor works seamlessly with modern ESCs that support brushless operation, and its compact 3650 form factor means it installs into vehicles designed for this standard motor size without requiring custom modifications. Whether running on 2S, 3S, or higher cell-count LiPo batteries (depending on your ESC specifications), this motor will perform reliably and efficiently, making it an excellent long-term investment for any serious RC car owner in the UK.
What's in the Box
- SPM Firma 3650-3400Kv 4-Pole Sensorless Brushless Motor with 5mm shaft
What You Need to Complete
- Compatible brushless ESC (electronic speed controller) rated for brushless motors
- LiPo battery pack (2S, 3S, or higher depending on ESC and vehicle requirements)
- Compatible RC vehicle chassis designed for 3650-size motors with 5mm shaft compatibility
- Pinion gear (typically 16T–23T depending on desired gearing)
- Battery charger with LiPo capability
- Radio control system and receiver (if not already installed in your vehicle)
Frequently Asked Questions
- Is the SPM Firma 3650-3400Kv motor suitable for beginners? — Yes, this motor is an excellent choice for drivers new to brushless RC systems. The sensorless design simplifies setup compared to sensored alternatives, and the 3400Kv rating provides forgiving power characteristics that are neither too aggressive nor too tame, making it accessible for learners whilst remaining capable enough for experienced drivers to enjoy.
- What is the difference between this 3400Kv motor and other Firma motors? — The Kv rating determines speed; higher Kv motors (such as 4000Kv+) spin faster and suit low-gearing setups or smaller vehicles, whilst lower Kv motors deliver more torque. The 3400Kv sits in the versatile middle ground, making it suitable for a broad range of vehicle types and battery configurations without requiring extreme gearing adjustments.
- What battery does the Firma 3650-3400Kv motor need? — This motor works with LiPo battery packs ranging from 2S (7.4V) through to higher cell counts, depending entirely on your ESC specification and vehicle type. Always check your ESC's voltage rating to ensure compatibility; most modern brushless ESCs support 2S–6S LiPo packs, and some support even higher voltages.
- Why choose a sensorless motor over a sensored one? — Sensorless motors eliminate the sensor cable and sensor pod required by sensored designs, reducing complexity, weight, and potential failure points. For most recreational and competitive RC driving, sensorless performance is indistinguishable from sensored operation, whilst offering greater simplicity and lower cost.
- Is the 3650 motor size compatible with my RC car? — The 3650 size is a widely adopted standard across the RC industry. Check your vehicle's motor mount and ensure it specifies compatibility with 3650-size motors and a 5mm shaft. Most modern touring cars, drift cars, buggies, and truggy vehicles accommodate 3650 motors.
- Can I use this motor for high-speed driving? — Absolutely. The 3400Kv motor is perfectly capable of delivering high speeds when paired with appropriate gearing and a suitable battery pack. Lower gear ratios will increase speed at the cost of acceleration and torque; adjust your pinion and spur gears to suit your preferred driving style and track conditions.
Why Buy from RC Model Shop?
RC Model Shop is a trusted UK RC retailer and authorised dealer for all the brands we stock, including Traxxas, ARRMA, Losi, FTX, Hobbywing, Spektrum and more. Based in Walsall, we have a physical store where customers are welcome to come in, view products and purchase in store. Whether you are a seasoned competitor, a weekend basher, or just discovering the world of RC for the first time, our team of experienced RC enthusiasts is here to help you find the perfect setup and provide ongoing support. Order the SPM Firma 3650-3400Kv 4-Pole Sensorless Brushless Motor: 5mm M-SPMXSM5500 today with confidence, knowing you are buying from an authorised retailer with genuine products, expert knowledge and a commitment to customer satisfaction. Shop online or visit us in Walsall — we look forward to helping you get the most out of your RC experience.
We want to make sure your delivery goes smoothly, so here are some important details about our service:
- For orders above £120, we offer delivery to most mainland UK addresses. For orders under £120, we can still deliver to Northern Ireland and the outlying isles, as long as the item can be sent by Royal Mail, weighs less than 30kg, and fits within 61cm × 46cm × 46cm. Some highland and remote areas may carry an extra delivery charge as couriers often apply surcharges in these locations. If you live in one of these areas, feel free to contact us before ordering so we can confirm the delivery options and costs for you.
- Most of our products include delivery in the price. If your order is under £90, a small delivery fee will apply but do not worry this will always be clearly shown at checkout before you complete your purchase.
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- If your order includes items with different dispatch times we will normally wait and send everything together once all items are in stock. If one of the items is going to take a while we will give you the choice either wait for everything to arrive or let us send the available items now and deliver the rest later. It is up to you.
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- For customers in Inverness and other parts of the Scottish Highlands deliveries can take up to 2 working days even if you select next day delivery as couriers do not currently offer a guaranteed next day service to those areas.
