HOBBYWING COMBO XR10 JUSTOCK G3S ESC/JUSTOCK G2.1 10.5T (Fixed Timing) HW38020370

Overview

The Hobbywing Justock Combo XR10 G3S ESC and G2.1 10.5T fixed-timing motor (model HW38020370) represents a complete, competition-ready power system designed specifically for 1/10th and 1/12th scale on-road and off-road racing in the UK and beyond. This combo delivers precise control and powerful performance tailored for zero-timing (blinky) specification racing, where fairness and consistency are paramount. Whether you are preparing for club competitions, weekend racing events, or serious training sessions, this Hobbywing combo offers the reliability and advanced features that discerning RC enthusiasts demand.

The pairing of the sophisticated XR10 Justock G3S speed controller with the G2.1 10.5T brushless motor creates a synergistic system optimised for stock and sport class racing. Built with precision engineering and robust protection features, this combo is not merely a collection of components—it is an integrated solution designed to work in perfect harmony. From intelligent thermal management to wireless data logging via Bluetooth, every aspect of this system reflects Hobbywing's commitment to performance, reliability, and competitive fairness. If you are searching for a brushless RC car power system in the UK that combines precision electronics with proven durability, the Justock Combo delivers exactly what serious racers expect.

The system is BRCA legal for club competitions in stock class racing, making it an ideal choice for drivers who want to compete on a level playing field. The zero-timing specification ensures that all competitors using this control system enjoy equal motor timing characteristics, eliminating an unfair advantage and focusing competition on driver skill, vehicle setup, and tuning.

Key Features

• XR10 Justock G3S ESC with precise zero-timing control — The integrated speed controller is specifically engineered for blinky (zero-timing) racing specifications, ensuring that your motor timing is fixed and fair for competitive racing. This takes the variable of motor timing completely out of the equation, allowing you to focus purely on driving skill and vehicle tuning.
• Intelligent fan control with automatic start and stop — The ESC features a smart fan system that only activates when the controller reaches a preset temperature threshold. This innovative function reduces unnecessary noise during low-temperature operation, conserves battery power, and ensures the ESC remains within its optimal operating temperature range throughout your racing session.
• Freewheeling function for improved handling and deceleration — When enabled, the freewheeling feature lowers ESC operating temperature, provides faster vehicle deceleration when throttle input is released, and delivers superior cornering control. This is especially valuable for drivers seeking better modulation during technical course sections and tighter turns.
• Built-in polarity protection safeguards your electronics — Accidental battery terminal reversal or short circuits can permanently damage speed controllers and motors. This ESC includes comprehensive polarity protection that prevents catastrophic failures caused by incorrect power connections, giving you peace of mind during setup and operation.
• 79 selectable RPM limit settings (10,000–88,000 RPM) — Different racing classes and competitions worldwide impose varying RPM restrictions to keep racing fair and equipment safe. This ESC supports 79 distinct RPM limit values, easily programmable via LCD programming box or OTA Bluetooth module, ensuring compliance with any competition ruleset without requiring controller replacement.
• Built-in capacitor module eliminates external components — Rather than requiring separate external capacitors, this ESC integrates the capacitor directly into its design. This optimised layout saves space on your chassis, reduces wiring complexity, and improves overall system reliability by eliminating potential failure points.
• Powerful 8A BEC with selectable voltage output — The integrated battery eliminator circuit can supply up to 8 amps of continuous current at either 6V or 7.4V, providing more than enough power for today's high-torque digital servos. Selectable voltage output lets you match your servo power requirements precisely, ensuring consistent servo performance throughout your racing session.
• Built-in data logging and real-time telemetry via OTA Bluetooth — The ESC records critical performance data including minimum voltage, maximum ESC temperature, maximum current draw, maximum motor temperature, and peak RPM. By connecting the optional OTA Bluetooth programmer and HW Link mobile application, you gain real-time access to telemetry data such as throttle position, voltage, current, temperature, and speed. This wireless data analysis (effective to approximately 5 metres) enables informed tuning decisions and performance optimisation.
• 60A continuous / 380A peak current handling — This substantial current capacity provides headroom for demanding motors and aggressive driving styles whilst maintaining stable, responsive throttle control. The 380A peak rating handles motor inrush current and acceleration pulses effortlessly, preventing voltage sag during hard acceleration.
• G2.1 10.5T fixed-timing brushless motor with Hall sensor — The paired motor features built-in Hall sensor technology, enabling consistent commutation and smooth, linear power delivery. The fixed 10.5T winding is optimised for stock class racing, delivering predictable performance across a wide range of driving conditions.
• Heat-resistant aluminium motor case with sealed design — The motor housing is constructed from heat-resistant aluminium, efficiently conducting internal motor heat to the outer case for better thermal management. A silicon O-ring seal between the end bell and stator protects the Hall sensor from dust and moisture while facilitating heat dissipation.
• High-precision bearings and dynamically balanced rotor — Double-insulated windings combined with precision bearings and a carefully balanced rotor guarantee smooth operation, minimal vibration, and exceptional durability even under sustained competitive use. This engineering delivers the linear, predictable power response that competitive drivers demand.
• Detachable motor design for easy maintenance — The motor's modular construction allows straightforward disassembly for cleaning and maintenance. Regular cleaning of the rotor and bearing surfaces can significantly extend the service life of your motor and maintain peak operating efficiency throughout the season.
• Compatible with all Hobbywing ESCs and other brands — The G2.1 motor is designed to work with the XR10 Justock ESC and is also compatible with other Hobbywing electronic speed controllers and speed controllers from other manufacturers, providing flexibility and upgrade options as your racing evolves.
• IFMAR and ROAR specification compliance — This motor design adheres to internationally recognised racing standards, ensuring compatibility with sanction body rules and regulations worldwide.
• Firmware upgrade capability — The ESC supports firmware updates, ensuring you can benefit from performance improvements and new features released by Hobbywing throughout the product's lifecycle.

Technical Performance

The XR10 Justock G3S ESC delivers exceptional performance through carefully engineered electronics and precision components. With a continuous current rating of 60 amps and peak capability of 380 amps, this controller handles the demanding power requirements of modern brushless 10.5T motors with ease, maintaining stable voltage output and responsive throttle control even under full acceleration. The ESC measures just 40.9 × 33.9 × 32.1 mm and weighs 75.4 grams including wiring, making it compact enough for space-constrained 1/10th and 1/12th scale chassis whilst remaining robust enough for repeated competition use. The integrated cooling fan (25 × 25 × 10 mm) automatically manages thermal conditions, keeping the controller operating within its optimal 5–7.4V range. Power input accepts 2S LiPo batteries exclusively (7.4V nominal), the standard for competitive 1/10th scale racing. The G2.1 10.5T motor features a 540 motor frame size with a brushless, sensored design offering 3650 KV (at 10.5T turn count), delivering smooth, linear acceleration and precise throttle response across all driving conditions. High-precision ball bearings and a dynamically balanced rotor minimise vibration and ensure longevity under competitive stress. The motor's heat-resistant aluminium case and sealed design protect internal components whilst efficiently dissipating heat generated during sustained racing efforts. Both components are non-waterproof, suiting them to covered track and club racing environments rather than extreme weather or water-crossing applications. The system's compatibility with IFMAR and ROAR standards, combined with zero-timing fixed specifications, makes it an excellent choice for drivers seeking a proven platform that delivers competitive fairness and engineering reliability.

What's in the Box

• Hobbywing XR10 Justock G3S electronic speed controller with pre-soldered 14 AWG battery and motor wiring
• Hobbywing G2.1 10.5T fixed-timing brushless motor with Hall sensor and heat-resistant aluminium case
• Motor mounting hardware and documentation

What You Need to Complete

• 2S LiPo battery pack (7.4V nominal) — essential power source for the system
• RC receiver and transmitter compatible with your chosen vehicle chassis
• Servo for steering control (the BEC output will power the servo)
• Vehicle chassis suitable for 1/10th or 1/12th scale on-road or off-road racing
• Connector adapters (optional) — various bullet connector options are available separately to match your existing charging and vehicle wiring infrastructure
• LCD Program Box Pro or OTA Bluetooth Programmer (optional but recommended) — required if you wish to adjust RPM limits, programming parameters, or access data logging features
• HW Link mobile application (free download) — enables wireless telemetry viewing and data analysis when used with the OTA Bluetooth module

Frequently Asked Questions

• Is the Hobbywing Justock Combo G3S suitable for beginners in RC racing? — Whilst this system is specifically engineered for competitive zero-timing racing rather than casual bashing, it can certainly be used by newcomers to the sport. The fixed-timing motor eliminates one variable, actually simplifying setup compared to adjustable-timing systems. However, beginners should expect to purchase programming equipment (LCD Program Box Pro or OTA Bluetooth module) to take full advantage of the system's competition-focused features. The dual-fan intelligent cooling and stable BEC output make it very forgiving for learning drivers.
• What battery does the Hobbywing Justock Combo require? — This system requires a 2S LiPo battery pack exclusively, meaning 7.4V nominal voltage (two cells at 3.7V each). The ESC is rated for input voltages between 5V and 7.4V, so a fully charged 2S battery (8.4V) will be within safe operating parameters. The continuous current capability is 60 amps, so select a 2S battery with at least 60C discharge rating for optimal performance; 100C or higher is recommended for competitive racing to minimise voltage sag during full throttle acceleration.
• Is this Justock system BRCA legal for UK racing competitions? — The XR10 Justock G3S ESC and G2.1 10.5T motor combo is BRCA legal for stock class club racing in the UK. However, the retailer's source material notes that it is NOT legal for 2024 Nationals competition in the 17.5T class or front-wheel-drive class. If you intend to race at the highest competitive level, verify current BRCA rules before purchase.
• What is zero-timing (blinky) racing and why does it matter? — Zero-timing means the motor commutation (switching) is fixed and not adjustable by the driver or tuner. This eliminates a significant variable that could otherwise give certain competitors unfair advantages. Blinky racing ensures all competitors using Justock-specification equipment compete on an absolutely level playing field based purely on driving skill, chassis setup, and mechanical tuning rather than electronics tweaking.
• How do I adjust RPM limits and access programming features? — The ESC can be programmed via the physical SET button on the controller itself for basic functions, but full access to all 79 RPM limit options requires either the LCD Program Box Pro (separate purchase) or the OTA Bluetooth Programmer (model 30850400). The LCD Program Box Pro accepts 5–12.6V input, whilst the OTA Programmer works wirelessly via Bluetooth 4.0 or higher at ranges up to 5 metres in open field conditions.
• Does this combo include a servo? — No, the combo includes only the ESC and motor. You must provide your own servo for steering control. The BEC output will power your servo at either 6V or 7.4V (user-selectable) with up to 4 amps of available current, more than sufficient for even high-torque digital steering servos.
• Can I use this motor with other speed controllers or ESCs? — Yes. The G2.1 10.5T motor is compatible with other Hobbywing electronic speed controllers (such as the EZRUN series) and with speed controllers from other manufacturers, provided they support sensored brushless motors and work with 2S LiPo batteries. However, for zero-timing racing, you must pair it with a zero-timing capable ESC such as the XR10 Justock G3S included in this combo.
• How does the intelligent fan control work and why is it useful? — The ESC continuously monitors its internal temperature. When the controller is cool (such as at the start of a race), the fan remains off, reducing noise and saving battery power. Once the ESC reaches a preset temperature threshold during sustained racing, the cooling fan automatically engages to prevent thermal shutdown. This intelligent approach means you get active cooling only when needed, extending battery runtime and reducing audible noise during low-intensity driving or practice sessions.
• What is the freewheeling feature and when should I use it? — Freewheeling mode reduces cogging when the throttle is released, allowing the motor to decelerate more freely and quickly. This feature lowers the ESC's operating temperature and improves vehicle handling during cornering, as the reduced drag makes the vehicle more responsive to steering inputs. Most competitive drivers enable this feature for improved control, especially on tight, technical race courses.
• Can I monitor my race performance with real-time telemetry? — Yes, when you add the optional OTA Bluetooth Programmer (30850400) and install the free HW Link mobile application on your smartphone or tablet, the ESC can stream live telemetry data to your device at ranges up to 5 metres. You will see real-time throttle position, battery voltage, current draw, ESC temperature, motor temperature, and speed. The system also records historical data which can be analysed after your racing session to identify performance trends and tuning opportunities.
• Is this system waterproof or weather-resistant? — No, both the ESC and motor are rated as non-waterproof. This system is designed for covered track racing, indoor environments, and dry conditions. It is not suitable for water crossings, heavy rain, or wet terrain racing. If you need waterproof electronics, you will need to explore alternative systems specifically designed with sealed connectors and conformal coating.

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 COMBO XR10 JUSTOCK G3S ESC/JUSTOCK G2.1 10.5T (Fixed Timing) HW38020370 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.