HOBBYWING COMBO XR10 JUSTOCK G3S ESC/JUSTOCK G2.1 17.5T (Fixed Timing) HW38020372

Overview

The Hobbywing Justock Combo HW38020372 represents the pinnacle of competition-ready RC car electronics, pairing the precision-engineered XR10 Justock G3S Electronic Speed Controller with the rock-solid G2.1 17.5T fixed-timing brushless motor. This matched combo is purpose-built for 1/10th and 1/12th scale on-road and off-road zero-timing (blinky) racing, where consistency, reliability and strict adherence to specification rules are paramount. Whether you're competing in club championships, BRCA-sanctioned events, or simply demanding the best performance from your RC car, this combo delivers the engineering excellence and fair-play compliance that serious racers demand across the UK and beyond.

The XR10 Justock G3S ESC is specifically designed to meet the exacting demands of competitive stock class racing, whilst the G2.1 17.5T motor provides smooth, linear power delivery with exceptional durability. Together, they form a cohesive system that has been optimised for competition needs, ensuring you get consistent lap times, predictable handling characteristics, and the reliability to push hard without worrying about equipment failure. This is a combo that speaks to serious competitors, dedicated hobbyists, and anyone who understands that buying quality electronics pays dividends in race results.

Manufactured by Hobbywing, a globally recognised leader in brushless motor and ESC technology, the HW38020372 combo delivers competition-grade performance that rivals purpose-built race kits costing considerably more. If you're searching for a brushless RC car setup that delivers genuine competitive advantage, zero-timing compliance, and engineering you can trust under pressure, this is the combo that delivers.

Key Features

• Intelligent Fan Control with Start/Stop Function — The ESC features an intelligent fan system that automatically activates only when the controller reaches a preset temperature threshold, rather than running continuously. This reduces noise pollution at the track, conserves battery power, and ensures the ESC operates within an optimal temperature range for peak efficiency. When conditions are cool, the fan stays silent; as temperatures rise, it engages automatically to maintain safe operating conditions.
• Freewheeling Function for Enhanced Handling — When enabled, the freewheeling feature reduces ESC temperature during deceleration and allows the vehicle to slow down more rapidly when you release the throttle, delivering sharper cornering control and more responsive handling characteristics. This translates directly to faster lap times and greater driver confidence when navigating technical sections of track.
• Built-in Polarity Protection — One of the most dangerous hazards in RC car systems is reversed battery polarity, which can occur through accidental terminal reversal or short circuits. This ESC incorporates sophisticated polarity protection that safeguards against this risk, protecting your investment and ensuring safe operation every time you power up.
• Multi-RPM Limiter with 79 Selectable Limits — Competition rules across the world impose different RPM restrictions depending on class and organisation. This ESC supports an impressive 79 different RPM limit settings spanning 10,000 to 88,000 RPM, easily programmable via LCD programming box or OTA wireless module. This flexibility means your setup remains competition-legal whether you're racing BRCA, IFMAR, ROAR or any other sanctioning body's specifications.
• Built-in Capacitor Module with Optimised Layout — The integrated capacitor module eliminates the need for external capacitor additions, saving space in your chassis and weight on your vehicle. The optimised PCB layout ensures cleaner power delivery and more stable voltage regulation under high current draw during acceleration and braking.
• High-Output 8A BEC with Selectable Voltage — The onboard Battery Elimination Circuit supplies up to 8 amps of continuous current at either 6V or 7.4V selectable output, ensuring consistently powerful servo operation even under demanding conditions. Modern high-torque servos require stable, ample power, and this BEC delivers exactly that without requiring a separate battery eliminator circuit.
• Built-in Data Logging and Performance Recording — The ESC continuously records critical operating data including minimum voltage, maximum controller temperature, peak current draw, maximum motor temperature, and top RPM achieved. This allows you to track performance across multiple runs and identify potential issues before they become problems.
• Wireless Data Analysis via OTA Bluetooth Module — When paired with the optional Hobbywing OTA Programmer and HW Link mobile app, the ESC transmits real-time telemetry data showing throttle input, voltage, current, temperature readings, and speed information. You can analyse session data graphically, identifying performance trends and tuning opportunities. The effective wireless range is approximately 5 metres in open field conditions.
• Programmable via Multiple Methods — Whether you prefer the simplicity of the onboard SET button, the comprehensive control of the LCD Program Box Pro, or the wireless convenience of the OTA Programmer, this ESC accommodates your preferred programming method with full support for firmware updates via all three systems.
• Fixed-Timing G2.1 17.5T Motor with Hall Sensor — The matched motor features fixed-timing construction (zero-timing compatible), built-in Hall effect sensor for smooth commutation, and is specifically optimised for stock class racing where consistency and reliability define winners.
• Premium Motor Construction — The motor utilises heat-resistant magnet materials, an aluminium case, double-insulated windings, high-precision sealed bearings, and a robustly-engineered rotor that guarantees exceptional durability and longevity under the demands of frequent racing.
• Non-Adjustable Hall Sensor End Bell — The sealed Hall sensor housing prevents interference and dust ingress, maintaining consistent sensor performance throughout the motor's operating life without requiring periodic recalibration or maintenance.
• Silicon O-Ring Seal Design — A silicon O-ring seal between the end bell and stator assembly conducts internal heat outward to the motor case while preventing dust and moisture from contaminating the sensitive Hall sensors, extending service life and reliability.
• Detachable Design for Easy Maintenance — The modular motor construction allows straightforward disassembly for cleaning and inspection, enabling you to maintain peak efficiency and identify wear components before they fail during a critical race.
• IFMAR and ROAR Specification Compliance — The motor design meets the stringent specifications of both IFMAR (International Model Auto Racing Federation) and ROAR (Radio Operated Auto Racing), ensuring full legal compliance for international and national competition.

Technical Performance

At the heart of this combo lies serious engineering designed specifically for competitive racing. The XR10 Justock G3S ESC delivers continuous current of 60 amps with peak capability reaching 380 amps during hard acceleration, providing the raw electrical power to exploit every fraction of performance from your 17.5T motor. The controller operates on 2S LiPo battery only (7.4 volts nominal), a specification universally mandated in stock class racing worldwide, ensuring you're never at a disadvantage due to power system choice. The ESC's compact dimensions of 40.9 x 33.9 x 32.1 millimetres and featherweight 75.4 grams (including wiring harness) integrate seamlessly into tight modern chassis designs, whilst the framed 25 x 25 x 10 millimetre cooling fan maintains thermal stability during extended racing sessions. The voltage operating range of 5.0 to 7.4 volts accommodates fully-charged 2S LiPo packs and manages voltage sag gracefully under peak current demand. The matched G2.1 17.5T motor features a 540-size aluminium motor can, fixed-timing brush design, and sensored brushless architecture with integrated Hall sensor, designed to pair perfectly with this ESC's firmware optimisation for predictable, linear power delivery. With support for 2S LiPo batteries only, you're assured competition compliance and simplified setup. The combo's engineering represents thousands of hours of dyno testing, track validation, and competitive feedback distilled into a system that prioritises consistency and reliability over raw power.

What's in the Box

• XeRun XR10 Justock G3S Electronic Speed Controller (30112005)
• Hobbywing G2.1 17.5T fixed-timing brushless motor with Hall sensor
• ESC input wiring harness: 1x black 14AWG 200mm wire, 1x red 14AWG 200mm wire
• ESC output wiring harness: 3x black 14AWG 200mm wires

What You Need to Complete

• 2S LiPo battery (7.4V nominal) with appropriate discharge rating for 60A continuous ESC current
• RC car chassis and body compatible with 1/10th or 1/12th scale brushless setups
• Servo(s) rated for high-torque applications (the 8A BEC will power modern high-output servos reliably)
• RC radio system with receiver compatible with your vehicle (sold separately)
• Battery charger suitable for 2S LiPo charging
• Motor and ESC connectors (various 3.5mm and 4mm bullet connector options available separately)
• LCD Program Box Pro (recommended, sold separately) or OTA Programmer (optional, sold separately) for full programming capability

Frequently Asked Questions

• Is the Hobbywing XR10 Justock G3S legal for BRCA racing in the UK? — The XR10 Justock G3S is not BRCA legal for 2024 Nationals in the 17.5T Control class or FWD class. If you require BRCA-legal electronics for those categories, Hobbywing manufactures alternative controllers (HW30112003, HW38020321, HW30408011) specifically approved for those classes. Always check current BRCA rules before purchasing for competition.
• What battery does this combo require? — The HW38020372 combo requires a 2S LiPo battery only (7.4 volts nominal). Do not attempt to use higher cell-count batteries (3S, 4S) as the ESC is designed exclusively for 2S operation. Choose a battery with adequate discharge rating to support the 60A continuous current draw of the ESC, typically 50C minimum.
• Is this combo suitable for beginners? — Whilst this is undoubtedly a high-quality combo, it is specifically engineered for competitive racing rather than casual bashing or beginner use. The zero-timing motor requires precise tuning knowledge, and competition racing demands understanding of concepts like timing advance, RPM limiting, and ESC programming. Beginners would benefit more from a brushless starter kit specifically designed for learning.
• What programming options does the ESC support? — The ESC can be programmed in three ways: via the onboard SET button for basic adjustments, through the LCD Program Box Pro (sold separately) for comprehensive parameter control, or wirelessly via the OTA Programmer (sold separately) using the HW Link mobile app on iOS and Android devices. All three methods support firmware updates.
• Can I use this motor with other brushless ESCs? — Yes, the Hobbywing G2.1 17.5T motor is compatible with other Hobbywing Electronic Speed Controllers and controllers from other brands, provided they support sensored brushless motors. However, the pairing with the XR10 Justock G3S represents Hobbywing's optimised configuration for zero-timing racing.
• What makes this combo different from individual ESC and motor purchases? — This combo is factory-matched and optimised specifically for zero-timing stock class racing. The firmware in the ESC is tuned for this precise motor, ensuring the smoothest possible power delivery and most linear throttle response. Buying a combo guarantees the best performance versus purchasing components separately.
• What data can the built-in data logger record? — The ESC records minimum voltage, maximum ESC temperature, maximum current, maximum motor temperature, and maximum RPM achieved. With the optional OTA Programmer connected, it also provides real-time telemetry streaming and historical graphing of throttle, voltage, current, temperature, and speed data via the HW Link app.
• How does the intelligent fan system work? — Rather than running continuously, the cooling fan activates only when the ESC temperature exceeds a preset threshold. This reduces track noise, saves power consumption, and maintains optimal operating temperature. As the controller cools, the fan disengages automatically.
• What is the effective range of the wireless OTA Programmer? — The Bluetooth-based OTA Programmer has an effective operating range of approximately 5 metres in open field conditions. This distance is sufficient for pit-side programming and data analysis during practice sessions and races.
• Is this combo waterproof? — No, the XR10 Justock G3S ESC and G2.1 17.5T motor are not waterproof and are not rated for water-fording or wet conditions. They are designed exclusively for dry-weather track racing. If you require waterproof electronics for off-road bashing in wet conditions, Hobbywing manufactures sealed alternatives.

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 17.5T (Fixed Timing) HW38020372 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.