As electric biking evolves, a growing number of UK riders are pushing beyond the limits of standard 250W or 1000W e-bikes. Enter the 72V 4000W ebike kit with battery — the next level of raw speed, torque, and range for riders who want more than just a commute.
Why Choose a 72V 4000W Ebike Kit?
The surge in demand for ultra-high-performance e-bike kits in 2025 reflects a shift in what riders expect. It's no longer just about going electric — it's about going faster, further, and harder. A 4000W electric bike kit with battery doesn’t just help you climb hills; it flattens them. It doesn’t just keep up with traffic — it leaves it behind (on private land, of course).
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Thrill-seekers looking to push speed limits on private trails
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Long-distance riders who want serious battery range
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Steep hill climbers who demand high torque and power output
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DIY builders converting fat bikes, mountain bikes, or e-moto frames
Whether you’re upgrading a rugged MTB or building a custom electric beast from scratch, the 4000W setup delivers unbeatable performance without the price tag of a high-end factory model.
How It Beats Lower-Voltage Kits
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Higher top speeds (80–90 km/h)
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Increased acceleration and torque, especially on inclines
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Greater range, especially when paired with a 72V 40Ah battery
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Smoother delivery of power through a sine wave controller
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Future-proof performance for off-road or custom e-moto builds
What Makes a 4000W Kit Special?
Regarding high-performance electric bikes, watts mean power — and 4000W is in a class of its own. A 4000W ebike kit isn’t just a modest upgrade from your average 1000W setup; it’s a total transformation in how your bike handles, accelerates, and climbs.
What Does 4000W Really Deliver?
A 72V 4000W ebike kit with battery produces intense torque and acceleration right from a standstill. That means:
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Instant throttle response
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No hesitation on hills — even with a heavy rider or cargo
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Superior pulling power, even off-road or in headwinds
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Effortless cruising at 60–70 km/h on flat terrain
This level of output rivals some low-end electric motorcycles — and when paired with a high-capacity battery like our 72V 40Ah lithium pack, you get speed and stamina.
So, How Fast Is a 4000W Ebike?
On private property or closed circuits, a properly tuned 4000W electric bike kit with battery can reach speeds of:
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80–90 km/h (50–55 mph) depending on load and terrain
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With pedal assist, even higher short-term bursts are possible
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Smooth power band means no sudden cutoffs or jerky acceleration
72V 4000W Ebike Kit with Battery: Complete Overview
Looking for the most powerful ebike conversion kit in the UK? The 72V 4000W Ebike Kit is engineered for serious riders who want maximum speed, torque, and long-distance performance — without compromising on build quality or support.
Motor: 72V 4000W Brushless Rear Hub
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Type: Direct-drive brushless hub motor
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Output: 4000 watts (peak)
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Torque: High-output design for extreme hill climbing
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Durability: Maintenance-free design with sealed construction
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Mounting: Rear wheel (cassette compatible)
Battery Options: High-Capacity Lithium Packs
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Battery: 72V 40Ah Lithium Battery
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Estimated Range: 70–120+ km per charge (varies by terrain, weight, and assist mode)
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Cells: Premium lithium-ion
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Protection: Built-in BMS for overcharge, discharge, temp, and short-circuit safety
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Charging: 5A or 8A fast charger included
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Mount Options: Triangle frame or rear rack (based on setup)
This 72V 40Ah battery delivers extended riding time with stable, high-current output — making it the perfect match for the 4000W motor.
Who Should Buy the 72V 4000W Ebike Kit?
The KirbEbike 72V 4000W ebike kit with battery is not for the casual commuter — it's built for riders who crave ultimate speed, torque, and range. If you're upgrading from a standard 250W–2000W setup, this kit unlocks a whole new level of performance.
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Off-Road Enthusiasts: Whether you ride steep mountain trails, gravel paths, or forest tracks, the massive torque from the 4000W hub motor and sinewave controller delivers unbeatable climbing power.
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Long-Range Adventurers: With a 72V 40Ah lithium battery offering up to 120+ km per charge, this kit is made for riders who need distance without constant charging.
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Speed Seekers: Capable of reaching 80–90 km/h (on private land), this kit transforms your bike into a high-performance machine that rivals small motorbikes.
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Builders & Custom E-bike Creators: If you're building a custom frame or high-spec project bike, this kit offers the raw power, modular components, and scalability serious builders look for.
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Heavy Riders or Cargo Builds: The added torque is ideal for heavier riders or utility e-bikes hauling loads — including food delivery, trailers, or panniers.
What You Can Expect from 72V 40Ah
When it comes to high-powered electric bike systems, the battery is just as important as the motor. KirbEbike’s 72V 40Ah lithium battery is engineered to match the intense power demands of the 4000W hub motor — delivering not just speed, but reliable long-distance performance.
Key Specs:
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Voltage: 72V
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Capacity: 40Ah
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Type: High-discharge lithium-ion (18650/21700 cells)
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Estimated Range: 70–120+ km per full charge
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Charge Time: 6–9 hours (with smart charger)
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Cycle Life: 800–1,000 full charges
Installation & Compatibility: What You Need to Know
One of the standout benefits of the KirbEbike 72V 4000W Ebike Kit is that it delivers massive power without requiring professional installation. Whether you're building a high-speed commuter or a rugged off-road beast, this kit is designed for DIY riders who want plug-and-play simplicity and broad compatibility.
What’s Included in the Kit?
Your 72V 4000W conversion kit comes with:
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72V 4000W rear brushless hub motor (spoked into rim)
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50A sine wave controller (smooth acceleration, heat-resistant)
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72V 40Ah lithium battery (optional, highly recommended)
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Color LCD Display (real-time speed, voltage, trip data)
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Pedal Assist Sensor (PAS)
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Thumb or Twist Throttle (your choice)
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Electric brake levers (auto motor cutoff)
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1T4 waterproof cable harness
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High-current connectors (XT90/Anderson)
Why Choose KirbEbike for High-Power Kits?
When it comes to 72V 4000W electric bike kits, not all brands are created equal. At KirbEbike, we focus on delivering real performance, rider safety, and flexible options — all backed by UK-based support and a no-hype, rider-first approach.
Here’s why thousands of UK and EU riders trust KirbEbike over other import-only or generic brands:
Purpose-Built Kits — Not Rebadged Imports
KirbEbike’s 72V 4000W kit is custom-developed for serious UK riders, with high-discharge batteries, sine wave controllers, and waterproof cabling — not generic rebrands sold without testing or after-sales support.
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Designed in-house for torque, speed, and reliability
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Real-world testing across the UK in hills, rain, and mixed terrain
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Available with matched 72V 40Ah lithium batteries built for 4000W loads
FAQs:
How fast is a 4000W ebike?
Up to 80–90 km/h on private land with the right battery.
Is it legal in the UK?
Not for public roads. Use on private property, farms, or trails.
What’s the range with a 72V 40Ah battery?
Typically 70–120 km depending on rider weight, terrain, and throttle use.
Can I install it myself?
Yes—DIY-friendly with plug-and-play wiring. KirbEbike includes full guides.
Is the 72V 4000W Kit Worth It?
If you're ready to unlock true performance and leave underpowered e-bikes behind, KirbEbike’s 72V 4000W kit is your best bet. With full power, long range, and UK support, it’s the most complete high-wattage e-bike conversion solution available.
