As more cyclists across the UK shift toward cleaner, faster, and more efficient travel, electric bike conversion kits have emerged as a popular solution. Instead of buying a completely new e-bike, these kits allow riders to upgrade their existing bicycle with electric power for a fraction of the cost.
Whether you're commuting through the city, climbing hills on weekend rides, or hauling cargo, a quality bike electric conversion kit can transform your experience. But with so many options available in 2025, choosing the right kit can be overwhelming. That’s why we’ve created this comprehensive guide to help you navigate your options and find the best fit for your riding style, terrain, and performance needs.
What Is an Electric Bike Conversion Kit?
An electric bike conversion kit is a bundle of components that transforms a standard bicycle into an electric bike. Most kits include:
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A motor (either hub motor or mid-drive)
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A battery with charger
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A controller (manages the flow of power)
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A display unit (shows speed, PAS, battery level, etc.)
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A throttle and/or Pedal Assist System (PAS)
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Sensors, cables, and mounting hardware
Many premium kits, such as those from KirbEbike, are now fully waterproof, plug-and-play, and can be installed in 30–60 minutes.
Why Convert Instead of Buy a Prebuilt E-Bike?
Electric bikes are fantastic — but they can be expensive, limited in customisation, and often lack the same geometry, sizing, or ride feel of your current bike.
Benefits of an Electric Conversion Kit:
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Cost-effective: Get powerful performance for less than half the price of a prebuilt e-bike
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Customisable: Choose your motor size, battery voltage, and throttle settings
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Keep your existing frame: Use the bike you already love and trust
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DIY-friendly: Install yourself with simple tools and online video tutorials
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Scalable: Upgrade batteries, motors, or controllers over time without buying a whole new setup
Types of Electric Bike Conversion Kits
There are two main types of conversion kits:
Hub Motor Kits (Front or Rear)
These place the motor in the hub of the wheel — either front or rear. They're easier to install and very popular.
Pros:
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Simple setup
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Lower cost
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Great for commuting and moderate hill climbing
Cons:
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Slightly less efficient on very steep hills
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Heavier unsprung mass (in rear hubs)
Mid-Drive Kits
These place the motor near the bottom bracket (pedal area) and power the drivetrain.
Pros:
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Better hill-climbing efficiency
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Leverages bike gears for smarter power usage
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Lower centre of gravity
Cons:
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More expensive
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More complex installation
How to Choose the Right Electric Bike Conversion Kit
Determine Your Power Needs
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250W: UK legal for road use, good for flats and light loads
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500W – 1000W: Good for hills, heavier riders, and light trail use
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1500W – 4000W: For off-road, high-speed, and extreme hill climbs (not UK road legal unless limited)
Choose the Right Battery
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Voltage: 36V (standard), 48V (stronger), 52V–72V (high power/performance)
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Capacity (Ah): Determines range. 13Ah = ~40km, 20Ah = 60–80km
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Look for smart BMS protection, waterproof design, and fast charging (4A–5A)
Check Compatibility
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Wheel size: Match your current size (20"–29")
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Dropout spacing: 135mm (standard), 175–190mm for fat bikes
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Brake system: Ensure disc brake compatibility
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Frame space: Ensure triangle space for battery mounting
Decide on Throttle or PAS (or both)
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PAS = pedal assist only
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Throttle = manual acceleration via thumb/hand
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Most premium kits offer both with display-based mode switching
Top Electric Bike Conversion Kits with Battery (UK Picks for 2025)
Here are some of the most trusted high-performance kits available in the UK market from KirbEbike:
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KirbEbike 52V 2000W MTX Kit
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Best for: Commuters and trail explorers
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Speed: 50–60km/h
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Torque: 60Nm
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Battery: 52V 20Ah or 30Ah
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Range: 60–80km
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UK Legal Mode: ✅ Yes (250W limiter)
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KirbEbike 60V 3000W MTX PRO Kit
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Best for: Mixed terrain, hills, and faster trail riding
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Speed: 70km/h+
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Torque: 80Nm
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Battery: 60V 20Ah LG + 5A fast charger
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Waterproof: IP66
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KirbEbike 72V 4000W MTX PRO Kit
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Best for: Fat tire bikes, steep climbs, and off-road power users
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Speed: 85–90km/h
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Torque: 110Nm
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Battery: 72V 20Ah LG/Samsung
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Display: 3.5” TFT, cruise, limiter, diagnostics
KirbEbike Kits at a Glance
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Feature
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52V 2000W
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60V 3000W
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72V 4000W
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Top Speed
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60 km/h
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70+ km/h
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85+ km/h
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Torque
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60Nm
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80Nm
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110Nm
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Max Range
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80km
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80km
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80km
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UK Legal Mode
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Yes
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Yes
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Yes
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Best For
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Commuting
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Mixed Terrain
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Off-Road
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Waterproof Rating
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IP65
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IP66
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IP66
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Installation & Maintenance Tips
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Kits come with all tools and accessories needed
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Setup time: 30–60 minutes for most users
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Use torque arm for motor safety
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Keep motor and connectors clean and dry
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Charge battery fully before first use, and avoid full drain cycles
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Store batteries in dry, moderate temps (10–25°C)
Road-Legal Use in the UK
In the UK, ebikes are legal for use on public roads only if they:
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Are pedal-assisted (no throttle-only operation)
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Have a motor rated at 250W or less
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Have max assisted speed of 25 km/h (15.5 mph)
KirbEbike kits include a legal mode toggle via display button to instantly reduce motor output to UK-compliant levels.
Pros & Cons of Electric Bike Conversion Kits
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Pros
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Cons
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Cost-effective alternative to e-bikes
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High-power kits are not road-legal at full speed
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Customisable for speed, power, and range
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Can be heavier than stock e-bikes
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Use your current frame and components
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Some setups require brake upgrades
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Scalable for future upgrades
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Battery mount may not fit all frame shapes
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FAQ: Electric Bike Conversion Kits
Q: Are conversion kits legal in the UK? A: Yes — if you enable 250W limit mode, your kit becomes road-legal.
Q: Can I install it myself? A: Yes! Most KirbEbike kits install in 30–60 minutes with simple tools.
Q: How far can I ride on a single charge? A: With 20Ah batteries, expect 40–80km range depending on speed and terrain.
Q: Can I switch between legal and full-power modes? A: Yes. Use the display toggle to switch between 250W (road) and full power (off-road).
Upgrade Smarter in 2025
Choosing the right electric bike conversion kit gives you the power to personalise your ride, save money, and gain the speed and torque you need for better cycling in any setting.
Whether you're commuting daily, hitting off-road trails, or simply want to future-proof your bike, kits from KirbEbike offer unbeatable value, UK-ready configurations, and high-performance features backed by expert support.
Best Upgrade for Your Ride
Upgrading your bicycle with a high-quality electric bike conversion kit is more than just adding a motor it’s transforming your ride into a performance machine. Whether you’re climbing hills, extending your range, or boosting your daily commute, a conversion kit gives you more control, more speed, and more value for your money.
Why it’s the best upgrade:
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Battery-powered freedom – Conquer longer rides without fatigue
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Modular design – Upgrade parts over time as your needs evolve
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Keep your existing bike – No need to sacrifice comfort or fit
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Lower cost than buying a new e-bike – Save hundreds of pounds
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Performance boost – Reach speeds of 50–85+ km/h depending on kit
Smart Features to Look For in a Modern Conversion Kit
The best electric bike conversion kits do more than just power your wheels — they offer an integrated riding experience. Smart displays, adaptive assist systems, and waterproof components have become standard in high-quality setups.
Must-Have Features in 2025:
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Multi-level PAS (Pedal Assist System) – Customize assist levels for terrain and battery savings
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Throttle control – Choose between pedal-only, hybrid, or throttle-only riding
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Legal mode toggle – Instantly limit power to 250W / 25km/h for UK road use
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Cruise control – Maintain speed on flat terrain without pedaling
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Walk assist mode – Push your bike uphill at 6km/h with no effort
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Battery diagnostics – Real-time status on voltage, charge cycles, and temperature
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Waterproof display and connectors – Ride through rain, snow, or mud without worry
