How We Choose the Best Kits

Our recommendations are based on real-world testing, user feedback, legal compliance, and long-term reliability. All kits meet US federal 750W power limits and are compatible with the three-class e-bike system.

Our evaluation criteria:

• Legal compliance with US e-bike regulations
• Installation difficulty and included components
• Real-world performance on hills and flats
• Long-term reliability and warranty support
• Value for money across different budgets

Best Overall Kits by Category

Best Overall: Bafang BBS02B Mid-Drive Kit

Why it wins: Perfect balance of power, features, and value with excellent US retailer support.

Key specs:

• Power: 750W mid-drive motor
• Voltage: 48V system
• Torque: 120Nm for excellent hill climbing
• Classes: Compatible with Class 1, 2, or 3
• Price range: $400-600 (motor only) / $800-1200 (complete kit)

What's included:

• BBS02B 750W mid-drive motor
• Color display with USB charging
• Gear shift sensor for smooth shifting
• Brake sensors for safety cutoffs
• All necessary cables and hardware

Best for: Riders who want mid-drive performance with proven reliability
Installation: Intermediate difficulty, 4-6 hours

Where to buy: Available from major US e-bike retailers with full warranty support

Best Budget: Voilamart 1000W Rear Hub Kit

Why it wins: Exceptional value with surprising performance and complete package.

Key specs:

• Power: 1000W rear hub motor (can be limited to 750W for legal compliance)
• Voltage: 48V system
• Type: Direct drive hub motor
• Classes: Class 1, 2, or 3 (with speed limiting)
• Price range: $300-450 (complete kit)

What's included:

• 1000W rear hub motor (26"/700c options)
• 48V 12Ah lithium battery
• Basic LCD display
• Throttle and pedal assist sensor
• Complete wiring harness

Best for: Budget-conscious riders who want a complete, functional kit
Installation: Beginner to intermediate, 2-4 hours

Legal note: Must be limited to 750W and appropriate speed limits for US compliance

Best for Hills: Bafang BBSHD 1000W (Delimited to 750W)

Why it wins: Maximum legal power with exceptional torque for steep climbs.

Key specs:

• Power: 1000W motor (software limited to 750W for US compliance)
• Voltage: 48V or 52V options
• Torque: 160Nm maximum torque output
• Classes: Class 1 or 2 recommended
• Price range: $600-800 (motor only) / $1200-1600 (complete)

What's included:

• BBSHD 1000W mid-drive motor
• Advanced color display
• Gear and brake sensors
• Programming cable for customization
• High-current controller

Best for: Riders tackling steep hills, heavy cargo, or demanding terrain
Installation: Intermediate to advanced, 5-8 hours

Important: Requires software limiting for US legal compliance

Best Lightweight: Tongsheng TSDZ2 Mid-Drive

Why it wins: Natural pedal feel with torque sensing and lightweight design.

Key specs:

• Power: 500W mid-drive motor
• Voltage: 48V system
• Weight: 7.7 lbs (motor only)
• Features: Torque sensor for natural feel
• Price range: $300-500 (motor only) / $700-1000 (complete)

What's included:

• TSDZ2 500W torque sensor motor
• Basic LCD display
• Torque sensor bottom bracket
• Speed sensor and brake levers
• Wiring harness

Best for: Riders who want a natural, bike-like pedaling experience
Installation: Intermediate difficulty, 4-6 hours

Best Hub Motor: Grin All-Axle Hub Kit

Why it wins: Premium hub motor system with unmatched customization and support.

Key specs:

• Power: Various options, 750W versions available
• Type: Geared or direct-drive options
• Voltage: 48V standard, other voltages available
• Features: Regen braking, temperature sensors
• Price range: $800-1400 (complete kit)

What's included:

• High-quality hub motor (multiple options)
• Cycle Analyst v3 computer
• Phaserunner controller
• Professional-grade wiring
• Comprehensive documentation

Best for: Experienced builders who want the ultimate hub motor system
Installation: Advanced difficulty, 6-10 hours

Complete Kit Recommendations by Budget

Under $500: Basic Reliable Conversion

Recommended kit: Generic 500W rear hub kit from established seller
Includes: Motor, basic battery, simple display, throttle
Performance: 20-30 mile range, 20 mph top speed
Best for: First-time converters, occasional use

$500-1000: Quality Mid-Range

Recommended kit: Bafang BBS02B with 48V 14Ah battery
Includes: Motor, quality battery, color display, sensors
Performance: 30-50 mile range, excellent hill climbing
Best for: Daily commuters, regular recreational riders

$1000-1500: Premium Performance

Recommended kit: Bafang BBSHD with 52V 17.5Ah battery
Includes: High-torque motor, premium battery, advanced display
Performance: 50-70 mile range, maximum legal power
Best for: Demanding use, long commutes, cargo hauling

$1500+: Professional Systems

Recommended kit: Grin complete system with Cycle Analyst
Includes: Premium components, advanced monitoring, customization
Performance: Optimized for specific use case
Best for: Enthusiasts, commercial use, custom applications

Kit Comparison by Use Case

Daily Commuting (15-25 miles)

Winner: Bafang BBS02B with 48V 14Ah battery
Why: Reliable, efficient, good range, reasonable cost
Alternative: Quality 750W geared hub kit for simpler installation

Weekend Recreation (20-40 miles)

Winner: Tongsheng TSDZ2 with 48V 17.5Ah battery
Why: Natural feel, good efficiency, adequate range
Alternative: Bafang BBS02B for more power reserve

Hilly Terrain/Mountain

Winner: Bafang BBSHD (limited to 750W) with 52V battery
Why: Maximum torque, high voltage for steep climbs
Alternative: BBS02B with high-capacity battery

Cargo/Heavy Duty

Winner: Bafang BBSHD with dual battery setup
Why: Maximum legal power, high current capability
Alternative: Quality 750W direct-drive hub for simplicity

Long Distance Touring

Winner: Grin All-Axle with large battery
Why: Efficiency optimization, regen braking, reliability
Alternative: BBS02B with multiple batteries

What's Included vs. What You Need

Typical Kit Inclusions

• Motor (hub or mid-drive)
• Controller
• Display unit
• Throttle (Class 2 kits)
• Pedal assist sensor
• Basic wiring harness
• Installation hardware

Additional Items Usually Needed

• Battery (often sold separately)
• Charger (may not be included)
• Installation tools (bottom bracket tools for mid-drive)
• Brake sensors (recommended for safety)
• Gear shift sensor (for mid-drive systems)

Professional Installation

• Cost: $200-500 depending on complexity
• Time: 3-8 hours depending on kit type
• Benefits: Warranty protection, proper setup, safety checks

Legal Compliance Notes

US Federal Requirements

• Maximum 750W continuous rated power
• Speed limits: 20-28 mph depending on class
• Pedal requirement: Must have functional pedals
• Age limit: 16+ years old

Making Kits US-Legal

• Power limiting: Software limit motors over 750W
• Speed limiting: Set appropriate cutoff speeds
• Class selection: Choose appropriate operating mode
• Display setup: Configure for proper power/speed limits

State-Specific Considerations

Some states have additional requirements:

• Helmet laws for certain classes or ages
• Licensing requirements (rare, mostly for Class 3)
• Trail restrictions vary by location
• Registration (uncommon but exists in some areas)

Installation Tips

Before You Buy

• Measure your bike: Wheel size, dropout width, bottom bracket type
• Check compatibility: Frame material, brake type, shifting system
• Plan electrical routing: Battery placement, wire management
• Budget for extras: Tools, additional components, professional help

DIY Installation Success

• Watch videos specific to your kit before starting
• Have proper tools especially for mid-drive installations
• Take photos during disassembly for reference
• Test thoroughly before final assembly
• Keep documentation for warranty and troubleshooting

Warranty and Support

What to Look For

• Minimum 1-year warranty on motor and electronics
• US-based support for faster service
• Replacement parts availability for long-term maintenance
• Installation support via phone or video
• Community forums for troubleshooting help

Red Flags to Avoid

• No warranty or very short warranty periods
• Poor English support makes troubleshooting difficult
• No replacement parts available in US
• Questionable safety certifications (UL, CE, FCC)
• Suspiciously cheap prices often mean poor quality

Future-Proofing Your Purchase

Technology Trends

• Improved battery chemistry with longer life
• Better motor efficiency and quieter operation
• Enhanced displays with smartphone integration
• Regulatory changes may affect legal requirements

Upgrade Path Planning

• Modular systems allow component upgrades
• Standard connections enable future compatibility
• Higher voltage systems provide upgrade headroom
• Quality brands maintain longer parts availability

Where to Buy

Recommended US Retailers

• Grin Technologies - Premium kits and components
• Electric Bike Outpost - Wide selection, good support
• EM3ev - Quality batteries and complete kits
• Luna Cycle - Performance-oriented systems
• Local bike shops - Installation and warranty support

What to Expect

• Shipping time: 3-10 days within US
• Import duties: Generally not applicable for US purchases
• Return policy: 30-day returns common for defective items
• Technical support: Phone/email support during business hours

Next Steps

Ready to choose your kit? Use our Smart Intent Wizard to get personalized recommendations based on your specific needs.

Need help understanding components? Check our Motor Selection Guide and Battery Basics for detailed technical information.

Want to see real examples? Visit our Build Gallery to see successful conversions using these kits.

Last updated: January 17, 2025

Try this: Use our Range Estimator with your chosen kit's specifications to verify it meets your daily riding needs before purchasing.