HOBBYWING JUSTOCK G2.1 17.5T SENSORED MOTOR (FIXED TIMING) HW30408011

Overview

The Hobbywing XERUN Justock G2.1 17.5T Sensored Motor with Fixed Timing (model HW30408011) represents the latest evolution in spec racing motors for the UK RC enthusiast. Following on from the success of the original Justock G2, this G2.1 version features fixed timing and easy-to-use solder joints, making it an excellent choice for stock or sport class racing where a controlled and reliable motor is essential. Whether you're competing in ROAR or IFMAR sanctioned events, or simply looking for a high-performance brushless motor for your 1/10th or 1/12th scale RC car, this Hobbywing motor delivers the precision engineering and consistent performance that serious racers and beginners alike demand from their RC equipment.

This sensored brushless motor has been specifically designed for competitors who need predictable power delivery and smooth acceleration characteristics. The 17.5T winding strikes an excellent balance between speed and control, making it ideal for both on-road touring cars, drifting vehicles, F1 scale models, mini cars, and off-road platforms including buggies, 2WD short course trucks and larger vehicles. The Justock G2.1 has earned its reputation as one of the most trusted spec racing motors available in the RC car UK market, and with good reason—the engineering quality, build durability, and racing pedigree are simply exceptional.

For those new to brushless motors or spec racing, the Justock G2.1 is a fantastic entry point. Its straightforward operation, compatibility with various ESC brands (particularly the XR10-Justock ESC), and beginner-friendly design make it perfect for training and practice sessions. For seasoned competitors, the fixed timing ensures compliance with competition rules whilst the Hall sensor technology guarantees the linear, smooth power delivery expected from a professional-grade racing motor.

Key Features

• Fixed Timing Design — The fixed timing configuration ensures absolute compliance with stock and sport class racing regulations across ROAR and IFMAR sanctioned events, eliminating any timing adjustments and providing consistent, rules-compliant performance every time you race.
• Heat-Resistant Magnet with Aluminium Case — Unlike earlier Justock G1 models that used iron cases, this G2.1 features a premium heat-resistant magnet assembly mounted within a high-quality aluminium case, which not only creates an aggressive, modern appearance but actively helps dissipate heat away from the motor windings for improved thermal management and longevity.
• Double Insulated Windings — The premium double insulation on the motor windings provides enhanced electrical safety and durability, protecting against moisture ingress and extending the operational lifespan of the motor in demanding racing conditions.
• Built-in Hall Sensor Technology — The integrated Hall sensor enables smooth, linear power delivery and precise speed control, essential for consistent lap times and predictable handling characteristics during competitive racing or practice sessions.
• Non-Adjustable End Bell — The fixed end bell assembly combined with the high-precision balanced rotor guarantees smooth and linear power on demand, eliminating the need for timing adjustments and ensuring plug-and-play compatibility with sensored ESCs.
• High Precision Japanese Bearings — Both the front and rear bearings (D9.525 x D3.175 x t3.967) are Japanese specification high-precision units that ensure minimal friction, smooth rotation, and exceptional durability under racing stress.
• Strong Rotor Construction — The structurally reinforced rotor design guarantees outstanding performance and increased durability, maintaining consistency lap after lap even during extended racing sessions or competitive events.
• Silicon O-Ring Seal Protection — A silicon O-ring seal fitted between the end bell and stator serves dual purposes: it actively conducts inner heat to the motor case for improved cooling, whilst simultaneously preventing dust and debris from entering the Hall sensor chamber, crucial for reliability in off-road conditions.
• Easy-to-Use Solder Tabs — The copper solder tabs with super low impedance at the load end of the motor allow direct soldering of ESC wires onto the tabs for solid, dependable electrical connections and simplified wiring—perfect for both competition builds and workshop maintenance.
• Rebuildable Design — The detachable end bell structure enables quick and straightforward daily cleaning and maintenance, with easy removal for replacement of common wearing parts such as the rotor and sensor module, effectively prolonging the service life of your motor and improving operating efficiency.
• Perfectly Matched with XR10-Justock ESC — Whilst this motor is compatible with other Hobbywing Electronic Speed Controllers and ESCs from other manufacturers, it has been specifically engineered and tuned for optimal performance with the dedicated XR10-Justock ESC for zero timing spec racing applications.
• Compliance with International Racing Standards — The motor design fully complies with IFMAR and ROAR racing specifications, making it legal and approved for use in sanctioned stock and sport class competitions across the UK and internationally.

Technical Performance

The Hobbywing XERUN Justock G2.1 17.5T motor delivers impressive technical performance across the board. At 2050 KV rating, this 17.5-turn motor is specifically calibrated for 2-3S LiPo battery systems, which represents the standard configuration for modern spec racing in 1/10th and 1/12th scale competition. The motor measures 35.9mm (1.413 inches) in diameter and 52.5mm (2.067 inches) in length, with a 3.17mm (0.125 inch) bore shaft diameter—standard 540-size dimensions that fit virtually every modern touring car, buggy, and off-road vehicle platform. Weighing just 176 grams (6.21 ounces), the compact and lightweight construction contributes to optimal weight distribution in your RC chassis. The no-load current draw of just 3 amps demonstrates the motor's efficiency and low power consumption, which translates to extended runtime and reduced strain on your battery and ESC. The 2-pole sensored brushless design ensures smooth commutation and precise speed control, with the integrated Hall sensor enabling proper motor synchronisation with compatible electronic speed controllers. The dual Japanese high-precision bearings (front and rear) provide the foundation for smooth, reliable operation, whilst the precision-balanced rotor ensures vibration-free running and consistent power delivery throughout the entire RPM range. This engineering excellence results in improved handling characteristics, more predictable acceleration, and ultimately faster lap times for competitive drivers.

What's in the Box

• Hobbywing XERUN Justock G2.1 17.5T Sensored Motor with Fixed Timing
• Motor with pre-soldered copper solder tabs ready for ESC connection
• Integrated Hall sensor (no external sensor cable required)

What You Need to Complete

• 2-3S LiPo battery (2S or 3S configuration recommended)
• Hobbywing XR10-Justock ESC or other compatible sensored brushless ESC
• Hall sensor cable to connect motor to ESC (various lengths available separately: part numbers 30850100, 30810000, 30850102, 30850103)
• Suitable RC vehicle chassis (1/10th or 1/12th scale on-road or off-road platform)
• Radio control system
• Charger compatible with your chosen battery chemistry

Frequently Asked Questions

• What is the difference between the 17.5T and other Justock G2.1 motor options? — The Justock G2.1 line includes 10.5T, 13.5T, 17.5T, 21.5T and 25.5T versions. The turn count directly affects motor speed and characteristics: lower turn counts (10.5T at 4000 KV) produce higher speeds, whilst higher turn counts (17.5T at 2050 KV) provide more torque and lower top speed. The 17.5T represents the midpoint for balanced speed and control, making it excellent for general racing and training, whilst the 21.5T and 25.5T options are additionally suitable for rock crawling applications requiring maximum torque.
• Is the Hobbywing Justock G2.1 17.5T suitable for beginners? — Yes, absolutely. Whilst this is a professional-grade competition motor, the Justock G2.1 is specifically recommended as an ideal choice for beginners and those looking for a practice motor. The smooth, linear power delivery enabled by the Hall sensor technology makes it very forgiving and easy to control, perfect for learning racing lines and developing driving skills without erratic power characteristics.
• What battery does this Hobbywing motor need? — This motor is designed to operate with 2-3S LiPo battery systems. Both 2S (7.4V nominal) and 3S (11.1V nominal) configurations are suitable, though 3S will provide noticeably higher performance. The choice between 2S and 3S depends on your specific chassis and ESC specifications—always refer to your ESC documentation for recommended battery configurations.
• Is this motor compatible with my existing ESC? — The Justock G2.1 is specifically designed for and perfectly matched with the Hobbywing XR10-Justock ESC for zero timing spec racing. However, it is also compatible with other Hobbywing Electronic Speed Controllers and sensored brushless ESCs from other manufacturers, as long as they support brushless sensored operation with Hall sensor input. Always verify that your ESC supports Hall sensor brushless motors before purchase.
• What makes the aluminium case better than the older iron case design? — The aluminium case used in the G2.1 (replacing the iron case from the original Justock G1) provides superior heat dissipation properties, actively conducting heat away from the motor windings to the external case where it can be dissipated. This improved thermal management keeps the motor cooler during extended running, improving performance consistency and extending the lifespan of the motor components.
• Can I maintain and rebuild this motor myself? — Yes, the Justock G2.1 features a rebuildable design with a detachable end bell that allows you to access and replace common wearing parts such as the rotor and sensor module, as well as the bearings. This design makes daily cleaning and maintenance straightforward, effectively prolonging the service life of your motor and improving its operating efficiency over time.
• What racing classes is this motor approved for? — The Justock G2.1 17.5T is designed for STOCK and SPORT class racing in both 1/10th and 1/12th scale competition, as per IFMAR and ROAR regulations. It is suitable for on-road racing including competition touring cars, drifting vehicles, F1 scale models and mini cars, as well as off-road racing including buggies, 2WD short course trucks and similar vehicles. The motor is perfectly legal and approved for sanctioned competition use.
• What is the purpose of the silicon O-ring seal? — The silicon O-ring seal serves two critical functions: it conducts internal heat from the motor windings towards the external aluminium case where it can be more effectively dissipated, improving thermal management, whilst simultaneously creating a seal that prevents dust and debris from entering the Hall sensor chamber—essential for reliability and longevity, particularly in off-road racing 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 HOBBYWING JUSTOCK G2.1 17.5T SENSORED MOTOR (FIXED TIMING) HW30408011 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.