Hobbywing XR10 Justock G3S + G2.1 21.5T Motor Combo – HW38020373

Overview

The Hobbywing XR10 Justock G3S ESC paired with the G2.1 21.5T fixed-timing brushless motor represents a premium, competition-grade power system engineered for serious racers. This matched combo delivers precision control and consistent zero-timing performance, making it an ideal choice for 1/10th and 1/12th scale on-road and off-road club competition. Whether you're competing in touring car races, drift events, buggies, or short-course trucks, this brushless RC combo offers the reliability and performance expected at competitive racing levels across the UK and beyond.

Built by Hobbywing, a manufacturer renowned for producing some of the finest electronic speed controllers and motors in the RC hobby, the XR10 Justock G3S represents the latest generation of stock-class racing technology. The 21.5T motor variant is particularly suited to drivers seeking a balance between torque and top-end speed, making it ideal for mixed-surface racing conditions and general club-level competition. This combo is not just for experienced racers—it's also an excellent upgrade path for enthusiasts looking to step up from entry-level brushed systems to serious brushless performance.

The engineering philosophy behind this combo focuses on competition compliance and real-world usability. The ESC features intelligent programming options that allow you to adapt to various racing formats and regulations worldwide, while the motor's fixed-timing design ensures consistent, predictable power delivery lap after lap. For anyone serious about RC car racing in the UK or competing at club events, the Hobbywing HW38020373 combo delivers the precision, durability and feature-richness you need.

Key Features

• XR10 Justock G3S Brushless ESC — The heart of this combo is a 60-ampere continuous (380-ampere peak) electronic speed controller specifically tuned for zero-timing stock-class racing, giving you the control precision and responsiveness required in competitive environments.
• Intelligent Fan Control with Start and Stop Function — The ESC features a sophisticated thermal management system that only activates the cooling fan when the controller reaches a preset temperature threshold, reducing noise and power consumption while ensuring the ESC operates within an optimal temperature range for peak performance and longevity.
• Freewheeling Function — When enabled, freewheeling reduces ESC temperature, allows faster vehicle deceleration when throttle input is released, and improves handling and controllability through corners—a critical advantage in competitive racing where smooth, predictable braking is essential.
• Advanced RPM Limiting with 79 Selectable Limits — The ESC supports RPM limits ranging from 10,000 to 88,000 RPM in 1,000 RPM increments, allowing you to comply with competition regulations worldwide or tailor performance to specific racing formats; programming is simple via LCD programming box or OTA wireless module.
• Built-In Polarity Protection — Accidental battery connection reversals—a common cause of ESC damage—are prevented by this protective circuit, safeguarding your investment against costly wiring mistakes.
• Integrated Capacitor Module — Rather than requiring external capacitors that add bulk and complexity, this ESC features an optimised internal capacitor design that eliminates clutter, improves layout efficiency, and reduces wiring requirements.
• Powerful 8-Ampere BEC with Dual Voltage Output — The built-in battery eliminator circuit can deliver up to 8 amperes at either 6 volts or 7.4 volts, providing sufficient power for today's high-torque servos without requiring a separate battery, simplifying your vehicle's electrical architecture.
• Built-In Data Logging Function — The ESC records critical operational data including minimum voltage, maximum temperature (both ESC and motor), maximum current draw, maximum RPM, and more—essential information for tuning and troubleshooting your racing setup.
• Wireless Data Recording and Real-Time Analysis via HW Link App — After connecting an optional OTA Bluetooth module, you can view real-time telemetry data through the HW Link mobile application, including throttle position, voltage, current, temperature and speed information within a 5-metre wireless range, enabling data-driven tuning decisions.
• G2.1 21.5T Fixed-Timing Brushless Motor — This generation-2.1 motor features a fixed-timing design that delivers consistent, predictable power characteristics essential for competitive racing, eliminating variable-timing complications and ensuring repeatable performance across multiple heat races.
• Heat-Resistant Magnet and Aluminium Housing — The motor's construction includes a heat-resistant magnet assembly mounted within a durable aluminium case, enabling superior thermal dissipation during extended racing sessions and ensuring the motor maintains performance even under sustained high-load conditions.
• Hall Sensor with Non-Adjustable End Bell — The built-in Hall effect sensor enables precise commutation timing, while the integrated non-adjustable end bell design guarantees consistent sensor alignment and eliminates field-adjustable complexity, ensuring smooth and linear power delivery on demand.
• High-Precision Bearings and Balanced Rotor — Precision ball bearings and a dynamically balanced rotor guarantee smooth operation, minimal vibration, and extended component lifespan—critical factors for maintaining competitive edge over multiple race seasons.
• Silicon O-Ring Seal for Thermal and Dust Protection — A silicone sealing ring fitted between the end bell and stator housing conducts internal heat to the motor case whilst preventing dust and debris from contaminating the Hall sensor assembly, extending service life and reliability.
• Detachable Motor Structure for Easy Maintenance — The motor's modular design allows straightforward disassembly for routine cleaning and inspection, enabling you to extend service life and maintain peak operating efficiency throughout the racing season.
• IFMAR and ROAR Specification Compliance — The motor design complies with international racing standards, ensuring compatibility with major competitive formats and guaranteeing this combo meets recognised performance specifications.
• Sensored Brushless Design — The sensored architecture provides smooth, controlled power delivery from zero RPM, perfect for precision launching and corner exit acceleration in competitive touring car racing.
• Compatible with Multiple Vehicle Types — This combo is engineered for 1/10th and 1/12th scale vehicles including on-road touring cars, drift cars, F1 models, mini cars, buggies, 2WD short-course trucks and off-road racing vehicles, offering versatility across multiple racing disciplines.

Technical Performance

The Hobbywing XR10 Justock G3S ESC delivers exceptional control authority with its 60-ampere continuous current rating and 380-ampere peak capacity, providing the power delivery and response necessary for competitive racing. The ESC measures a compact 40.9 × 33.9 × 32.1 millimetres and weighs approximately 75.4 grammes with integrated wiring, allowing installation in tight chassis spaces typical of modern 1/10th scale touring cars and buggies. Accepting 2S LiPo battery input (7.4 volts maximum), this system is designed for contemporary high-performance brushless racing where weight and packaging efficiency are paramount. The paired G2.1 21.5T motor offers a KV rating of 2,050, meaning it will spin approximately 2,050 revolutions per minute per volt of input under no-load conditions—a specification that balances top-end speed with the torque needed for responsive acceleration and smooth cornering. The 540-size brushless motor uses a 3.2-millimetre bore and delivers the fixed-timing characteristics essential for repeatable competitive racing performance. The 21.5T turn count (higher turn count = more torque, lower speed) is particularly suited to mixed-surface club racing where drivers require strong mid-range acceleration without excessive top-speed demands that would strain the ESC and motor. Input wiring is supplied as twin 200-millimetre black and red 14-gauge wires, whilst motor output wiring consists of three black 200-millimetre 14-gauge leads, allowing direct motor connection without additional connectors. The fan assembly measures 25 × 25 × 10 millimetres and activates intelligently based on ESC temperature thresholds. This combo represents serious engineering optimised for zero-timing specification racing, embodying Hobbywing's commitment to delivering components that survive the rigours of competitive club racing in the UK and internationally.

What's in the Box

• Hobbywing XR10 Justock G3S brushless electronic speed controller
• Hobbywing G2.1 21.5T fixed-timing brushless motor (540 size, 3.2mm bore)
• ESC input wires: 2 × black 14AWG 200mm, 2 × red 14AWG 200mm
• Motor output wires: 3 × black 14AWG 200mm
• 25mm × 25mm × 10mm cooling fan (pre-installed on ESC)

What You Need to Complete

• 2S LiPo battery (7.4 volt nominal, maximum 2S) with appropriate connectors
• Battery charging equipment (LiPo-compatible charger)
• Motor and ESC connectors (XT60, Deans, 4mm bullets, or 5mm bullets available as optional upgrade at point of purchase)
• Radio system (receiver and transmitter)
• Servo(s) for steering and throttle control
• 1/10th or 1/12th scale RC vehicle chassis
• Optional: LCD programming box (Hobbywing Multifunction LCD Program Box Pro) for advanced ESC programming
• Optional: OTA Programmer (Hobbywing OTA Programmer) for wireless programming and data analysis via HW Link mobile application

Frequently Asked Questions

• Is the Hobbywing XR10 Justock G3S suitable for beginners, or is it only for experienced racers? — Whilst this combo is engineered for competitive racing and stock-class compliance, it is also an excellent choice for serious hobbyists stepping up from brushed to brushless systems. The fixed-timing motor is more forgiving than adjustable-timing variants, and the intelligent ESC features make tuning straightforward. However, beginners with limited racing experience may find the advanced programming options and competition focus somewhat overwhelming compared to entry-level brushless combos. This combo is best suited to intermediate racers or beginners with dedicated mentorship.
• What battery does the Hobbywing XR10 Justock G3S require? — The ESC accepts 2S LiPo battery input only, with a maximum voltage of 7.4 volts. You cannot use 3S, 4S or higher-cell LiPo batteries with this controller, as doing so will damage the ESC. The combo also supports 4-9 cell NiMH battery packs if preferred, though LiPo batteries are vastly superior for modern RC racing performance. You will need a 2S LiPo charger compatible with your specific battery connector type.
• Can I use this combo in BRCA-sanctioned UK National racing? — The XR10 Justock G3S is not BRCA-legal for 2024 UK Nationals in the 17.5T control class or FWD category. If you intend to compete in these specific classes, you will need alternative ESC options such as the HW30112003, HW38020321, or HW30408011. For other racing formats and club-level events, this combo is fully competition-compliant.
• How do I programme the RPM limits and other settings? — The ESC supports 79 different RPM limit selections spanning 10,000 to 88,000 RPM in 1,000 RPM increments. Programming can be accomplished in three ways: via the SET button on the ESC itself (though this is basic), through a dedicated Hobbywing LCD Programming Box Pro (sold separately), or wirelessly using the optional Hobbywing OTA Programmer module paired with the HW Link mobile application. The LCD box and OTA module are separate purchases and highly recommended for serious racers who need to adjust settings quickly between heats.
• What is the difference between the G2.1 21.5T motor in this combo and other Hobbywing Justock motor variants? — The G2.1 nomenclature indicates this is the second-generation, first-revision design with fixed timing. The turn count (21.5T in this case) determines power characteristics: lower turn counts (10.5T, 13.5T) deliver higher speeds and lower torque, suited to high-speed tracks; mid-range counts (17.5T, 21.5T) balance speed and torque for mixed surfaces; higher counts (25.5T) prioritise torque for crawling and low-speed technical sections. The 21.5T variant offers excellent all-round performance for general club racing and is ideal if you're unsure which motor turn count suits your local racing conditions.
• Does this combo include waterproof electronics? — No. The XR10 Justock G3S ESC and G2.1 motor are not waterproof and are not suitable for water-based racing, muddy conditions, or wet terrain without protective enclosures. If you require waterproof electronics, you will need to source a dedicated waterproof ESC and motor combination.
• What data can the built-in data logging function record? — The ESC records the following extreme values: minimum battery voltage (useful for identifying low-battery performance issues), maximum ESC temperature, maximum motor temperature, maximum current draw, and maximum RPM achieved. This historical data is invaluable for diagnosing thermal issues, optimising gearing, and tuning throttle curves. Real-time data streaming and historical graph recording are supported through the optional OTA Programmer and HW Link app, enabling sophisticated performance analysis.
• How hot does the motor get during racing, and can I run extended heats without damaging it? — The motor's aluminium housing and heat-resistant magnet assembly are designed to handle sustained high-load racing. The built-in Hall sensor data logging records maximum motor temperature, allowing you to monitor thermal performance and identify whether your racing conditions exceed the motor's design envelope. Under typical club racing conditions (multiple shorter heats rather than continuous operation), the motor will remain within safe operating parameters. Extended continuous operation may raise temperatures; monitoring via the data logging function is essential.
• Is the 60-ampere continuous rating sufficient for 1/10th scale touring car racing, or do I need a higher-rated ESC? — The 60-ampere continuous rating is specifically matched to stock-class 1/10th touring car racing and is perfectly adequate for this discipline. Higher-amperage ESCs (80A, 120A+) are designed for modified classes and high-performance systems where motor currents demand exceed stock-class specifications. The 60-ampere XR10 Justock is engineered specifically for zero-timing racing and is overkill for anything beyond this class.
• Can I use this ESC and motor combo in off-road buggies or trucks, or is it only for on-road touring cars? — This combo is equally suitable for off-road applications. The manufacturer explicitly lists compatibility with 1/10th and 1/12th buggies, short-course trucks, and off-road racing vehicles. The fixed-timing motor and intelligent ESC features benefit both on-road precision racing and off-road terrain navigation. Ensure your vehicle's mechanical setup (suspension, gearing, tyres) is optimised for your chosen application.
• What is the effective wireless range for the OTA Programmer Bluetooth module? — The manufacturer specifies an effective range of approximately 5 metres for OTA Bluetooth connectivity. This is sufficient for trackside data monitoring and programming between heats but is not designed for long-distance telemetry transmission. The range may be reduced by electromagnetic interference, physical obstacles, or poor signal 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 XR10 Justock G3S + G2.1 21.5T Motor Combo – HW38020373 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.