Overview
The Spektrum Firma 1524 4500Kv Brushless Sensored Crawler Motor is a purpose-built drop-in upgrade for Axial SCX24 and AX24 rock crawlers, designed to elevate your 1/24 scale crawling experience to new heights. This high-precision brushless motor represents a significant advancement over standard brushed alternatives, offering excellent slow-speed control and smooth operation that is essential for technical trail driving and rock crawling competitions. Whether you're exploring challenging terrain or competing in organised events, this brushless RC crawler motor delivers the performance and reliability demanded by serious enthusiasts across the UK.
What makes the Firma 1524 particularly appealing is its complete integration with Axial's SCX24 and AX24 platforms. The motor comes as part of a comprehensive system that includes everything needed for installation, with pre-installed 2mm bullet connectors and compatibility with the standard JST PH 2.0 battery connector found on Axial RTR vehicles. This means you can upgrade your ready-to-run RC crawler without extensive modifications or sourcing additional components. For UK RC hobbyists looking to extract maximum performance from their micro crawlers, this Spektrum motor offers a trusted solution from a recognised brand with a reputation for quality and precision engineering.
The 4500Kv rating is specifically calibrated for low-speed crawling applications, providing the torque and control characteristics that separate competitive rock crawlers from casual bashers. Combined with advanced sensored control technology, this motor enables unprecedented responsiveness and consistency across variable terrain and driving angles, making it an ideal choice for anyone serious about their 1/24 scale crawling.
Key Features
- 4500Kv Sensored Brushless Motor — The 4500Kv rating is specifically engineered for crawling applications, delivering the low-end torque and precise speed control necessary for technical rock crawling and trail driving. Sensored design means the ESC reads rotor position feedback from the motor itself, enabling superior throttle response at any speed and any driving angle, something brushless sensorless alternatives simply cannot match.
- High-Precision Magnetic Encoder and Rotor Position Sensor — This advanced sensor technology provides exceptional 1:1 control feel when driving, allowing the ESC to match your throttle input to the motor's RPM with unmatched precision. This results in smooth, predictable operation whether you're crawling over rocks at walking pace or navigating technical obstacles that demand exact throttle modulation.
- Drop-In Conversion for Axial SCX24 and AX24 — Designed as a direct replacement for standard brushed motors in Axial 1/24 scale RTR vehicles, this motor integrates seamlessly into existing platforms without requiring modifications to your chassis, wiring harness, or mounting points. This makes upgrading your crawler straightforward and accessible for hobbyists of all skill levels.
- Compact 15mm Diameter Design — The 0.6 inch (15mm) outer diameter ensures the motor fits perfectly within the tight confines of 1/24 scale vehicles whilst maintaining sufficient power delivery. This compact footprint is essential for micro crawlers where space is at a premium and weight distribution directly impacts performance on technical terrain.
- Maintenance-Free Operation Over Brushed Motors — Brushless motors eliminate the carbon brushes and commutator found in brushed alternatives, removing the need for regular cleaning, maintenance, and eventual brush replacement. This translates to longer service life, reduced downtime, and more hours of uninterrupted crawling between servicing intervals.
- Optimised for Efficiency and Extended Runtime — The brushless design and sensored control work together to maximise battery efficiency, allowing you to extract more crawling time from each charge compared to brushed motor alternatives. This efficiency gain is particularly noticeable during extended trail sessions and competition events.
- Pre-Installed with 2mm Bullet Connectors — The motor arrives ready to connect, with 2mm bullet connectors already fitted to the motor leads. This eliminates connector compatibility concerns and ensures robust electrical connections that won't loosen during aggressive crawling sessions.
- JST PH 2.0 Battery Compatibility — The integrated connector matches the Dynamite 7.4V 350mAh 2S LiPo battery included with Axial SCX24 and AX24 RTR vehicles, ensuring plug-and-play battery compatibility without the need for additional adapters or modifications.
Technical Performance
The Firma 1524 motor delivers technical performance specifically calibrated for 1/24 scale rock crawling applications. Rated at 4500Kv, the motor produces a maximum RPM of approximately 16,200 at full throttle on a 2S LiPo battery (7.4 volts nominal), though the sensored control system prioritises precision and throttle fidelity over raw top speed, making it perfect for crawling work where controlled, predictable operation matters far more than velocity. The motor features a two-pole magnetic circuit design, which contributes to the smooth torque delivery characteristic of high-Kv motors intended for micro-scale applications. Weighing just 16 grams, the motor is exceptionally light for a brushless unit, minimising unsprung mass and helping maintain weight distribution that is critical to climbing performance on difficult obstacles. The outer diameter of 15mm ensures packaging compatibility with Axial's tight motor mounting cavities, and the 12mm height and 27mm length are precisely engineered to fit the standard 1/24 scale chassis layout. When paired with the included 8-amp continuous rated ESC (capable of 40-amp burst), this motor system can handle the power demands of vigorous crawling sessions whilst maintaining the control precision that separates this system from alternatives. The sensored technology continuously reads motor rotor position feedback, enabling the ESC to deliver instantaneous throttle response that feels natural and intuitive whether you're attempting a delicate uphill crawl, executing a precise line over rocks, or performing a rapid downhill descent where engine braking and instant reverse are critical. For UK hobbyists upgrading from standard brushed setups, the performance difference is immediately noticeable—smoother operation, faster response, better speed consistency, and the ability to maintain control at extremely low speeds without the stuttering or cogging common in brushed alternatives.
What's in the Box
- Firma 1524 4500Kv Brushless Sensored Motor
- Firma 8-Amp Sensored Brushless Electronic Speed Controller (ESC)
- Sensored motor connector cable with magnetic encoder sensor
- Pinion gears for drivetrain compatibility
- Pre-installed 2mm bullet connectors on motor leads
- JST PH 2.0 battery connector for Axial standard batteries
What You Need to Complete
- 2S LiPo Battery (7.4V) — The motor and ESC are compatible with 1-2S LiPo batteries; the Axial SCX24 and AX24 platforms typically use Dynamite 7.4V 350mAh 2S packs, which are widely available from UK RC retailers
- Battery Charger — If you don't already own an RC battery charger capable of charging 2S LiPo batteries, you'll need one to keep your crawler powered between sessions
- Note for certain SCX24 models — Axial SCX24 vehicles equipped with the HRZ00014 2-in-1 receiver and HRZ00015 transmitter (including 2021 Ford Bronco, Jeep GT Gladiator, and Jeep Wrangler variants) will require an SLT3 transmitter and receiver upgrade for full compatibility with this sensored ESC system; refer to the instruction manual for detailed upgrade information
Frequently Asked Questions
- Is the Spektrum Firma 1524 4500Kv motor suitable for beginners upgrading from standard brushed motors? — Yes, this motor is specifically designed as a drop-in replacement for Axial SCX24 and AX24 vehicles, making it accessible for hobbyists without advanced technical knowledge. The sensored control actually makes the motor easier to drive smoothly compared to brushed alternatives, as the closed-loop feedback system provides more intuitive throttle response. However, some specific SCX24 variants require a receiver upgrade—check your model's compatibility before purchasing.
- What battery does the Firma 1524 motor require? — The motor and ESC system is compatible with 1-2S LiPo batteries. Axial SCX24 and AX24 RTR vehicles ship with a Dynamite 7.4V 350mAh 2S LiPo battery, which features a JST PH 2.0 connector that matches the pre-installed connector on this motor system. You can use any 2S LiPo battery with this connector type, or 1S batteries if you prefer slower, even more controlled crawling.
- What is the difference between the Firma 1524 sensored motor and a brushless sensorless alternative? — Sensored motors like the Firma 1524 read rotor position feedback through a magnetic encoder, allowing the ESC to deliver instantaneous, precise throttle response at any speed. Sensorless motors rely on back-EMF feedback and typically exhibit cogging and delay at very low speeds. For rock crawling where predictable, smooth operation at walking pace is essential, sensored control is significantly superior.
- Is this motor waterproof? — The Firma 1524 motor itself is not water-resistant. Whilst the motor and ESC can tolerate light moisture from damp terrain, they should not be submerged or exposed to heavy rain or water crossings. For wet-weather crawling, consider protecting electronics with additional conformal coating or silicone sealant.
- What is the maximum continuous current rating? — The included 8-amp ESC provides 8 amps of continuous current with a 40-amp burst capacity. This is appropriate for the 4500Kv motor in crawling applications and well-matched to 2S LiPo battery capabilities in the SCX24 platform.
- Does this require soldering or can I install it myself? — The motor comes with pre-installed 2mm bullet connectors and the ESC includes a pre-fitted JST PH 2.0 battery connector, so soldering is not required. Installation is straightforward—simply disconnect your existing motor, mount the new Firma motor in place of the old one, and plug in the battery connector. The sensor cable must be routed to the ESC, but this is a simple mechanical task requiring no electrical knowledge.
- What is included for transmission compatibility? — The system includes pinion gears suitable for Axial SCX24 and AX24 drivetrains, ensuring proper mesh and performance once installed in your chassis.
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 1524 4500Kv Brushless Sensored Crawler Motor, SCX24 M-SPMXSM3900 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.
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