Quick answer: The RFN Warrior SX-E400 is a compact 12-inch electric dirt bike designed to give younger riders a genuine motocross-style experience with manageable power, suspension and three selectable speed settings.
Best for: riders aged around 3–6 and approximately 90–110cm tall who already balance confidently and want their first proper electric motocross-style bike.
RFN Warrior SX-E400 Electric Bike UK
The RFN Warrior SX-E400 electric bike is the smallest and most manageable model in the RFN Warrior Kids range.
Designed for younger riders, it combines compact 12-inch wheels, front and rear suspension, a removable lithium battery and adjustable speed settings with the appearance and riding position of a proper miniature motocross bike.
It is a natural option for children who have progressed beyond a basic balance bike and want something more substantial without immediately moving onto the larger RFN Warrior SX-E500.
At Garland Powersports, we stock the RFN Warrior SX-E400 with fast UK delivery, specialist sizing advice and access to the wider RFN Warrior Kids range.
What Is the RFN Warrior SX-E400?
The RFN Warrior SX-E400 is a small electric dirt bike aimed at younger riders who want a more realistic motorcycle-style experience than a traditional electric balance bike can provide.
It uses proper footrests, motocross-style bodywork, suspension and a twist throttle rather than pedals or a bicycle-style riding position.
The SX-E400 is still designed to remain manageable. Its compact dimensions, 12-inch wheels and three selectable speed settings give parents more control over how quickly the rider progresses.
It is intended for recreational off-road use on private land and suitable designated riding areas with the landowner’s permission.
Why Choose the RFN Warrior SX-E400?
The SX-E400 offers a useful bridge between a lightweight electric balance bike and a larger kids electric dirt bike.
It gives young riders the chance to learn motorcycle-style throttle control, foot positioning and braking without immediately placing them on a larger or more powerful machine.
Compact Size
The smallest RFN Warrior Kids model, designed around younger and shorter riders.
Three Speed Settings
Parents can restrict the available performance while the rider builds confidence.
Proper Suspension
Front suspension and a rear mono shock improve comfort and control over uneven ground.
Removable Battery
The 36V lithium battery can be removed for convenient indoor charging and storage.
Who Is the RFN Warrior SX-E400 For?
The RFN Warrior SX-E400 is generally recommended for riders aged around 3–6 years old and approximately 90–110cm tall.
These figures should be used as a guide rather than a guarantee of fit. Rider confidence, strength, inside leg measurement and previous experience all matter.
A confident child who already balances well on a bicycle or balance bike may be ready for the SX-E400. A very small or cautious child may still prefer a lighter electric balance bike.
RFN Warrior SX-E400 rider guide
- Age guide: around 3–6 years
- Height guide: approximately 90–110cm
- Maximum rider weight: approximately 50kg
- Best rider type: beginner to developing young rider
- Useful experience: balance bike, bicycle or smaller electric bike
- Best terrain: grass, dirt and light private off-road areas
- Next step: RFN Warrior SX-E500
Is the SX-E400 suitable for a first electric bike?
Yes, provided the child already has reasonable balance and is physically large enough to manage the bike.
The SX-E400 weighs approximately 18kg, making it more substantial than a typical electric balance bike. A rider should be able to support the bike, reach the controls and follow instructions from a supervising adult.
RFN Warrior SX-E400 Key Specifications
| Specification | RFN Warrior SX-E400 |
|---|---|
| Motor | 36V 250W electric motor |
| Rated output | 400W |
| Torque | Approximately 26Nm |
| Battery | 36V 5.2Ah removable lithium-ion battery |
| Battery capacity | 187Wh |
| Speed settings | Three selectable performance levels |
| Maximum speed | Up to approximately 15.5mph |
| Maximum range | Up to approximately 11 miles in suitable conditions |
| Full charging time | Approximately 160 minutes |
| 80% charging time | Approximately 120 minutes |
| Brake | 140mm rear disc brake |
| Suspension | Front suspension and rear mono shock |
| Ground clearance | Approximately 125mm |
| Wheels | 12-inch front and rear wheels |
| Bike weight | Approximately 18kg |
| Maximum rider weight | Approximately 50kg |
Speed, range and riding time vary according to rider weight, speed mode, terrain, temperature and riding style.
Three Adjustable Speed Settings
The SX-E400 includes three selectable speed settings, allowing parents to reduce the available performance while the rider learns.
This is one of the most useful features on the bike because it allows the same machine to remain suitable as confidence improves.
Built for Gradual Progression
The lowest setting can be used while the rider develops basic throttle and braking control.
The middle setting provides a useful progression for normal riding, while the highest setting unlocks the SX-E400’s full performance once the rider is ready.
- Start in the lowest mode
- Practise accelerating and stopping
- Progress only when control is consistent
- Use the highest mode only in a suitable riding area
Motor Performance
The SX-E400 uses a quiet electric motor with a rated output of 400W.
Its performance is designed around younger riders rather than outright speed. The power delivery is smooth and controllable, particularly in the lower modes.
This helps riders learn how to use a twist throttle without the noise, heat or maintenance associated with a small petrol engine.
The motor gives the bike enough performance for grass, dirt and light inclines while remaining manageable for its intended rider.
Battery, Range and Charging
The RFN Warrior SX-E400 uses a removable 36V 5.2Ah lithium-ion battery.
The removable design makes it easier to charge the battery indoors and store it away from extreme temperatures.
- 36V 5.2Ah lithium-ion battery
- 187Wh energy capacity
- Removable battery pack
- Up to approximately 11 miles of claimed range
- Approximately 160 minutes for a full charge
- Approximately 120 minutes to reach 80%
Actual riding time depends on rider weight, terrain, speed mode and throttle use.
Soft grass, hills and repeated full-throttle acceleration will reduce the available range compared with steady riding on firm, level ground.
Front and Rear Suspension
The SX-E400 is equipped with front suspension and a rear mono shock.
This gives it a more comfortable and controlled ride over uneven ground than a rigid electric balance bike.
The suspension helps absorb smaller bumps across grass, dirt and light private off-road terrain while contributing to the bike’s motocross-style appearance.
It is designed for recreational riding rather than unrestricted jumping or full competition motocross use.
Rear Disc Brake
The SX-E400 uses a 140mm rear disc brake.
The rear-only setup keeps the braking system straightforward for younger riders who are still learning basic control.
Before each ride, an adult should check that the brake works correctly and that the rider can comfortably reach and operate the lever.
Riders who are ready for separate front and rear braking may be better suited to the larger SX-E500.
12-Inch Wheels and Off-Road Tyres
The SX-E400 uses 12-inch wheels, helping keep the bike compact and manageable for younger riders.
The wider tyres provide useful grip across grass, dirt and other natural riding surfaces.
The 12-inch setup also makes the SX-E400 relevant for customers comparing the best 12-inch electric bikes for children.
For a wider comparison, read our guide to the best 12-inch electric bikes for kids in the UK.
Where Can the RFN Warrior SX-E400 Be Ridden?
The SX-E400 is intended for off-road use on private land and suitable designated riding areas with the landowner’s permission.
Suitable surfaces may include:
- Private gardens with enough space
- Grass fields
- Private paddocks
- Dirt tracks
- Light woodland trails
- Suitable beginner practice areas
The bike is not road legal and should not be used on public roads, pavements or cycle paths.
RFN Warrior SX-E400 vs SX-E500
The SX-E400 and SX-E500 share the same motocross-style concept, but they suit different rider sizes and confidence levels.
| Feature | SX-E400 | SX-E500 |
|---|---|---|
| Best For | Younger and smaller riders | Growing and more confident riders |
| Rated Output | 400W | 500W |
| Maximum Speed | Approximately 15.5mph | Approximately 18.5mph |
| Wheels | 12-inch | 14-inch |
| Brakes | Rear disc brake | Front and rear disc brakes |
| Best Rider Type | First electric dirt bike | Confident beginner or developing rider |
Choose the SX-E400 for a younger or smaller rider who needs the most manageable model in the RFN Warrior range.
Choose the SX-E500 for a taller and more confident rider who wants larger wheels, separate front and rear braking and more room to progress.
Read our complete RFN Warrior SX-E400 vs SX-E500 comparison before deciding.
How Does the SX-E400 Compare With an Electric Balance Bike?
The SX-E400 and a traditional electric balance bike provide different riding experiences.
An electric balance bike is usually lighter, simpler and easier for a complete beginner to manoeuvre.
The SX-E400 feels more like a miniature motorcycle because it uses footrests, suspension, motocross-style bodywork and a more substantial chassis.
| Electric Balance Bike | RFN Warrior SX-E400 |
|---|---|
| Usually lighter and easier to carry | More stable and substantial dirt-bike chassis |
| Bicycle-style riding position | Motorcycle-style riding position with footrests |
| Best for simple balance development | Best for learning throttle and dirt-bike control |
| Often easier for complete beginners | Better for confident riders wanting the MX experience |
Is the RFN Warrior SX-E400 Worth Buying?
The RFN Warrior SX-E400 is worth considering for a young rider who wants a proper electric motocross-style bike and is ready to progress beyond a lightweight balance-bike platform.
Its strongest features are the manageable dimensions, three speed settings, suspension and removable battery.
It is not automatically the right choice for every three- to six-year-old. Rider size and confidence should be considered carefully, especially because the bike is heavier than a traditional balance bike.
For the correct rider, the SX-E400 provides a strong introduction to electric off-road riding and a clear progression path into the SX-E500.
Why Buy the SX-E400 From Garland Powersports?
Garland Powersports specialises in kids electric bikes and electric off-road machines rather than selling the SX-E400 as one item within a general toy range.
That specialist focus allows us to help customers compare the RFN Warrior models and choose a bike based on the rider’s size, confidence and riding experience.
Specialist Advice
Clear help comparing the SX-E400 with the SX-E500 and other kids electric bikes.
UK Stock
RFN Warrior SX-E400 bikes available through our UK stock and warehouse network.
Fast UK Delivery
Fast delivery options when the selected SX-E400 colour and model are in stock.
Full RFN Range
Compare the SX-E400, SX-E500 and SX-E700 before making your final decision.
Read our Best Place to Buy RFN Warrior SX-E400 UK guide for more information.
My Take as a British Motocross Rider
The SX-E400 is a good starting point for a younger rider who wants something that looks and feels like a genuine motocross bike.
What makes it work is the ability to keep the performance restricted while the rider learns. They can focus on balance, throttle control and braking without needing the full speed immediately.
It is heavier and more substantial than a small electric balance bike, so I would still make sure the rider is physically big enough and confident on two wheels.
For the correct-sized child, the SX-E400 is a strong first step into electric off-road riding and the most manageable model in the RFN Warrior range.
RFN Warrior SX-E400 FAQs
What age is the RFN Warrior SX-E400 for?
The SX-E400 is generally recommended for children aged around 3–6 years old. Rider height, confidence and previous experience should also be considered.
What height rider is the SX-E400 for?
The usual rider height guide is approximately 90–110cm.
How fast does the SX-E400 go?
The RFN Warrior SX-E400 has three selectable speed settings and reaches up to approximately 15.5mph in its highest mode.
Can parents restrict the speed?
Yes. Parents can choose between three performance settings so the bike can be restricted while the child learns.
How long does the SX-E400 battery last?
The SX-E400 has a claimed maximum range of approximately 11 miles in suitable conditions. Actual riding time depends on terrain, rider weight, speed mode and throttle use.
Is the battery removable?
Yes. The 36V 5.2Ah lithium-ion battery can be removed for charging and storage.
How long does the battery take to charge?
A full charge takes approximately 160 minutes, while an 80% charge takes around 120 minutes.
Does the SX-E400 have suspension?
Yes. It has front suspension and a rear mono shock.
Does the SX-E400 have front and rear brakes?
No. The SX-E400 uses a rear disc brake. The larger SX-E500 uses separate front and rear disc brakes.
Is the SX-E400 suitable for beginners?
It can suit a beginner who already balances confidently and is physically large enough to manage the bike. A very small or cautious child may find a lightweight electric balance bike easier.
Should I buy the SX-E400 or SX-E500?
Choose the SX-E400 for a smaller and younger rider. Choose the SX-E500 for a taller or more confident rider who wants larger wheels and additional performance.
Is the SX-E400 road legal?
No. It is intended for private land and suitable off-road riding areas with the landowner’s permission.
Does the rider need protective equipment?
Yes. Riders should wear a correctly fitting helmet, gloves, suitable boots and protective clothing. Adult supervision is essential.
Do you offer UK delivery?
Yes. Garland Powersports offers fast UK delivery when the selected SX-E400 is in stock.
Explore the RFN Warrior Kids Range
Still deciding which model is suitable? Read our RFN Warrior Kids range explained guide.
RFN Warrior SX-E700
The premium performance model for riders ready for more power and hydraulic brakes.
Shop SX-E700Buy the RFN Warrior SX-E400 Electric Bike in the UK
The RFN Warrior SX-E400 is a strong first electric dirt bike for younger riders who want a proper motocross-style machine in a manageable package.
It combines 12-inch wheels, three adjustable speed settings, front and rear suspension and a removable lithium battery with a compact chassis designed for riders around 90–110cm tall.
Shop the RFN Warrior SX-E400 electric bike online with Garland Powersports today.