Overview
The Losi 1/4 Promoto-SM FXR Supermoto Motorcycle RTR represents the most authentic supermoto experience ever offered in a radio-control bike. This ready to run RC motorcycle combines fresh styling with proven Promoto mechanical and electronic technologies to deliver outstanding on-road performance. Whether you're a seasoned RC enthusiast or discovering the world of radio-controlled vehicles for the first time, this 1/4 scale supermoto brings genuine motorcycle riding dynamics to concrete, asphalt, blacktop, and other hard surfaces found at neighbourhood streets, local parks, and parking lots across the UK.
Powering off the line, speeding down straights, and leaning through curves and turns, a unique harmony develops between the Promoto-SM and its rider. The two intuitively become one. Despite its powerful brushless motor capable of 40+ mph speeds, the two-wheeler feels light and nimble as it reacts instantly to your control inputs—as if it's simply an extension of you. That's exactly how it feels to drive Losi Promoto RC bikes. The Losi Promoto-MX was the first RC dirt bike to accurately reproduce the full experience and pure fun of riding a real motorcycle. Now, for on-road RC and motorcycle enthusiasts, Losi presents the Promoto-SM—a breakthrough in supermoto RC technology that no other ready to run RC bike can match.
This brushless RC motorcycle is fully assembled and ready to run straight out of the box. Battery and charger are included, along with everything you need to start driving within minutes. The package includes the Spektrum Smart DX3PM transmitter, a 5000mAh 2S 7.4V Smart G2 LiPo battery, the Spektrum Smart S120 USB-C charger, and comprehensive documentation. Whether you're purchasing your first ready to run RC motorcycle or adding to an established collection, the Promoto-SM delivers professional-grade performance with beginner-friendly operation thanks to Spektrum's intuitive control systems and three selectable drive modes.
Key Features
- Patent-pending Spektrum MS6X Technology — The included Spektrum DX3PM transmitter and SR6300PM receiver combine with innovative MS6X technology for unprecedented control and balance at any speed. This system enables the Promoto-SM to maintain stability whilst leaning through corners on hard surfaces, whilst also allowing you to increase lean angle using the MS6X knob for more aggressive driving and extreme cornering angles.
- Three On-The-Fly Drive Modes — Toggle between Dirt Mode (which prevents wheelie-overs by intelligently clipping throttle output), Street Mode (which quickly clips throttle when pitching up to keep the front tyre on the ground for maximum acceleration), and Wheelie Control (which lets you hold wheelies all the way to top speed on smooth surfaces). Simply use the A/B rocker switch on the DX3PM transmitter to switch modes whilst driving.
- Updated Lean Bar System with Bearings — The Promoto-SM lean bar positioning has been updated so it can lean farther than the dirt bike counterpart. New rubber lean bar tyres mounted on bearings reduce noise and offer superior traction on hard surfaces. Adjustable stops for up and down travel let you dial in the bike for any surface or grip level, and the lean bars often help with crash recovery when the rear tyre has traction.
- Powerful Brushless Motor and Flywheel Stabilisation — A 2700Kv brushless motor spins a frame-integrated, high-RPM steel flywheel at over 22,000 rpm to create gyroscopic force for unparalleled stability. The flywheel is mounted as low and as far forward as possible in the frame, enabling the Promoto-SM to pivot around its centre point to improve jumping, changes of direction, and overall performance accuracy.
- Advanced Front and Rear Braking System — An innovative dual-brake setup cuts the stopping distance in half compared to rear brake only systems. The all-new front brake caliper and floating piston design applies larger pressure area to the brake pad, whilst a new Metal Injection Moulded piston shaft installed on bearings provides smoother operation and better sealing against dust and debris for consistent braking performance.
- Supermoto-Specific Styling and Tyres — This ready to run RC motorcycle features officially licensed FXR graphics and realistic rider figure with authentic riding gear. Pro-Line Racing OE (Original Equipment) SM street tyres on smaller wheels deliver supermoto-style performance, whilst the shortened front fender and hand guards create an authentic supermoto appearance you won't find on standard RC motorcycles.
- Rising Rate Rear Suspension — Losi's product development team studied full-size motorcycle suspension geometry to give Promoto RC bikes the same terrain handling characteristics as real motorcycles. The rising rate rear suspension provides superior grip and prevents bottoming out in landings, working in harmony with the front fork design to deliver professional-level handling.
- Tunable Front Fork with Internal Spring and Dampener — The completely new front fork design features an internal spring and dampener that can be tuned by changing the silicone dampening fluid. Ride height adjustments allow you to optimise the bike for different surfaces and riding styles, giving you comprehensive control over suspension performance.
- Intelligent Head Damping and Servo Saver — A fluid-filled friction chamber between the upper and lower head tube bearings, filled with heavy 500,000cSt dampening fluid, controls head shake and stabilises the servo saver. The servo saver's stiff circular springs captured by bearing-mounted composite plates provide consistency in steering with enough give to protect the servo, whilst dramatically improving performance when setting down from wheelies, landing from jumps, and power sliding through turns.
- Collapsible Front Crash Structure — The innovative design protects the front of the motorcycle whilst absorbing impact during crashes, reducing repair costs and downtime so you can get back to driving faster.
- Dual Disc Performance Slipper Clutch with Chain Drive — The chain drive system features a dual disc performance slipper clutch that prevents wheel spin during hard acceleration and protects the drivetrain from shock loading, improving overall reliability and performance.
- Spektrum Smart Technology Integration — LED indicators on the DX3PM transmitter show remaining battery capacity at a glance. The included Spektrum Smart 5000mAh 2S LiPo battery stores and shares critical performance data, with charging requirements uploading automatically to compatible smart chargers. Optional upgrade to a Spektrum DX5C or DX5 Pro transmitter provides real-time telemetry including speed, RPM, amp draw, and ESC temperature.
- Comprehensive Ready to Run Package — Everything needed to drive is included in the box: fully assembled motorcycle, Spektrum DX3PM transmitter with 4 AA batteries, 5000mAh 2S battery, Smart S120 charger with IC3/IC5 adapter, bike stand, starting stand, product manual, quick start guide, and chain lube. No additional components or subscriptions required.
Technical Performance
The Losi 1/4 Promoto-SM FXR combines cutting-edge mechanical and electronic engineering to deliver performance unmatched by previous RC motorcycle designs. Powered by a Spektrum Firma 3652 3800Kv 4-Pole brushless motor paired with a Spektrum Firma 85A brushless Smart motorcycle ESC, this ready to run RC bike achieves 40+ mph top speed with responsive, smooth acceleration. The motor size and Kv rating are specifically tuned for the 1/4 scale platform, delivering the power needed for supermoto-style riding whilst maintaining precise control through corners. The electrical system uses a 2S LiPo battery platform (Spektrum 5000mAh 2S 7.4V Smart G2 50C) offering excellent runtime and rapid recharge capability with the included Smart charger.
The chassis features 3mm aluminium plate construction providing an ideal balance between rigidity and weight savings. The Promoto-SM measures 504mm in length, 259mm in width, and 424mm in height, with a wheelbase of 353mm and ground clearance of 57mm—dimensions precisely engineered for smooth on-road surfaces. The complete assembled motorcycle weighs 3540 grams (129.4 oz), distributed optimally with the motor and flywheel mounted in the frame's centre for superior balance and handling characteristics. The 1/4 scale platform delivers an impressive physical presence whilst remaining highly manoeuvrable for street and parking lot driving.
Suspension engineering demonstrates the attention to detail throughout this design. The front features a newly designed fork with 16mm big bore aluminium shocks offering internal spring and dampener tuning via silicone fluid changes. The rising rate rear suspension delivers geometry that mirrors full-size motorcycle characteristics, providing superior grip without bottoming out. The drivetrain features a 12.0:1 final drive ratio with 32-pitch gearing, 20T pinion, and 50T spur gear, along with 4.8:1 internal gear ratio providing optimal power delivery and acceleration characteristics.
The braking system represents a major upgrade over earlier motorcycle RC designs. Dual 16mm big bore aluminium shocks pair with full ball bearing construction throughout the chassis, supporting the cable-driven front disc brake system that shares stopping duties with rear motor braking. This dual-brake approach cuts stopping distance in half compared to single-brake systems. The Pro-Line Racing OE SM street tyres (35S compound) mounted on smaller wheels than the MX variant provide superior traction and noise reduction on concrete and asphalt surfaces, essential for on-road supermoto performance. Front and rear wheel widths measure 28mm and 36.3mm respectively, optimised for hard-surface grip.
Radio control comes from the Spektrum DX3PM 2.4GHz Smart DSMR transmitter paired with the Spektrum 6-Channel DSMR Promoto receiver, offering rock-solid connection and real-time data sharing with Smart batteries. Steering control uses the Spektrum S620PM metal gear servo, whilst front brake control utilises the Spektrum SX108PM micro servo—both selected for reliability and precision at 1/4 scale. The LiPo compatibility is 2S only, optimised for the Spektrum 5000mAh 2S smart battery included in the box. Assembly time is less than one hour for new owners, and the RTR (Ready-to-Run) configuration means unboxing, charging, and driving can happen on the same day.
What's in the Box
- (1) Losi Promoto-SM 1/4 Supermoto Motorcycle RTR FXR—fully assembled and ready to run
- (1) Spektrum Smart DX3PM Transmitter with 2.4GHz DSMR technology
- (4) AA Transmitter Batteries for the DX3PM
- (1) Spektrum 5000mAh 2S 7.4V Smart G2 50C LiPo Battery with IC5 connector
- (1) IC5 Device to IC3 Battery Adapter for charger compatibility
- (1) Spektrum Smart S120 USB-C Charger, 1x20W output
- (1) Bike Stand—keyed stand for stable parking
- (1) Starting Stand—hands-free starting support
- (1) Product Manual with comprehensive setup and tuning guidance
- (1) Quick Start Guide for rapid deployment
- (1) Chain Lube for drivetrain maintenance
- Tuning Parts including fork and shock adjustment tools
What You Need to Complete
Nothing. Everything you need is included in the box! The Losi 1/4 Promoto-SM FXR arrives fully assembled with battery, charger, transmitter, and all accessories required to begin driving within minutes of unboxing.
Frequently Asked Questions
- Is the Losi Promoto-SM suitable for beginners in RC motorcycles? — Yes, this ready to run RC bike is excellent for newcomers to radio-controlled motorcycles, particularly those with some general RC experience. The three preprogrammed drive modes (Dirt, Street, and Wheelie Control) make it accessible for learning, whilst the patent-pending MS6X technology handles much of the balance automatically. Street Mode is recommended for beginners as it prevents wheelie-overs by intelligently managing throttle. However, some users prefer to start with an RC car before moving to the unique challenges of motorcycle control, as RC motorcycles require different riding techniques than four-wheeled vehicles.
- What is the top speed of this ready to run RC motorcycle? — The Losi Promoto-SM FXR achieves 40+ mph top speed, delivered by the Spektrum Firma 3652 3800Kv brushless motor and Spektrum Firma 85A ESC. Actual speeds vary based on battery charge state, driving surface conditions, riding style, and environmental factors such as temperature and air density.
- What battery does this RC motorcycle need and how long does it run? — The Promoto-SM uses a 2S LiPo battery platform exclusively. The included Spektrum 5000mAh 2S 7.4V Smart G2 50C battery provides excellent runtime for a 1/4 scale motorcycle, typically 15-25 minutes of continuous driving depending on riding intensity and surface conditions. The battery charges via the included Spektrum Smart S120 USB-C charger, which features automatic charging parameter uploading from the battery's memory microchip. Additional 2S LiPo batteries are available separately to extend driving sessions.
- How does the Promoto-SM differ from the Promoto-MX dirt bike? — Whilst both share the same core mechanical and electronic platforms, the Promoto-SM is specifically optimised for on-road surfaces. Key differences include: Pro-Line Racing OE SM street tyres on smaller wheels versus knobby dirt tyres; updated lean bar positioning and rubber lean bar tyres with bearings for reduced noise and improved hard-surface traction; a more powerful front brake caliper and piston for improved stopping power; and distinctive supermoto-style body panels with shortened front fender, hand guards, and officially licensed FXR graphics. The Promoto-SM can lean farther than the MX and features tuned suspension geometry optimised for concrete, asphalt, and blacktop rather than dirt and grass.
- Can I upgrade or modify the Promoto-SM after purchase? — Yes, the Promoto-SM supports extensive customisation. The front fork features tunable internal spring and dampener via silicone fluid changes, with ride height adjustments available. Adjustable lean bar travel stops allow dial-in for different surfaces and grip levels. The suspension geometry can be modified through replacement parts. Optional parts, fork tools, shock tools, and tuning parts are available separately from authorised Losi retailers. However, always follow the manufacturer's recommendations and consult the product manual before modifying any safety-critical components.
- What is Spektrum Smart Technology and why does it matter? — Spektrum Smart Technology enables automatic data sharing between compatible batteries, chargers, and transmitters. The included Spektrum Smart 5000mAh 2S battery's charging requirements upload automatically to the Smart S120 charger, eliminating guesswork and ensuring optimal charge parameters every time. LED indicators on the DX3PM transmitter display remaining battery capacity at a glance. If you upgrade to a Spektrum DX5C or DX5 Pro transmitter, you gain real-time telemetry data including speed, RPM, amp draw, and ESC temperature—providing detailed performance monitoring during driving sessions.
- Is assembly required or does it arrive ready to run? — The Losi Promoto-SM FXR arrives fully assembled and ready to run (RTR). Approximate assembly time is less than one hour if any disassembly or inspection is needed before first drive, but the motorcycle is drivable immediately after unboxing, charging the included battery, and inserting AA batteries into the transmitter.
- What drive modes are available and how do I switch between them? — Three preprogrammed drive modes come factory-configured in the DX3PM transmitter. Dirt Mode allows pitching up for jumps whilst preventing wheelie-overs through intelligent throttle clipping. Street Mode rapidly clips throttle when pitching up to keep the front tyre grounded for maximum on-road acceleration. Wheelie Control allows full throttle wheelies on smooth surfaces all the way to top speed. Toggle between modes on the fly using the A/B rocker switch on the DX3PM transmitter whilst driving—no stop required.
- What makes the brake system special on this ready to run RC motorcycle? — The Promoto-SM features an innovative dual-brake system combining cable-driven front disc brake (piston/caliper/rotor configuration) with rear motor braking. This design cuts stopping distance in half compared to rear brake only systems. The all-new front brake caliper and floating piston apply larger pressure area to the brake pad. The new Metal Injection Moulded piston shaft installed on bearings ensures smoother operation and better dust/debris sealing. This system is more powerful and consistent than earlier motorcycle RC designs.
- Can I use standard rechargeable AA batteries or do I need the included ones? — The DX3PM transmitter requires 4 AA batteries to operate. Four standard AA alkaline or rechargeable NiMH batteries are included. Rechargeable NiMH AA batteries are generally recommended for ongoing operation due to cost savings and environmental benefits, though alkaline batteries work as backup. Ensure fresh batteries are installed to maintain full transmitter range and performance.
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 LOS 1/4 Promoto-SM FXR Supermoto Motorcycle RTR (Batt & Charger) C-LOS-2310 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.
