QR-E PRO-MAX-400W +H70-300wh Kit
428$
Power & Performance
Motor Output: 400W Continuous Power (Reliable, sustained performance)
Assisted speed: The motor supports assistance up to 28 mph (45 km/h) in testing. Actual speed varies, and local limits apply.
Operating Modes: *ECO: Optimized for maximum range.
Sports: Strongest assistance, for hills and headwinds.
Regenerative Braking: Up to 240W power recovery during deceleration.
Rotation: Supports two-way rotation for versatile installation.
Battery & Range
Model: H70 High-Capacity Battery
Energy: 300Wh
Weight: Ultra-light at 1.5kg
Dimensions: 73 x 230mm
Estimated Range: Up to 72km (Assisted riding/Pedaling)
Note: Range figures are real-world customer averages. Assisted-speed figures describe motor capability measured in testing, not a target speed — always ride within local limits.
Compatibility & Installation
Suitable Bike Types: City bikes, Road bikes, Folding bikes, and Off-road bikes (equipped with road tires).
Installation Requirement: Requires a compact space of only 7 x 5cm for mounting.
Shipping & Pricing
All-Inclusive Pricing: Price includes VAT; no hidden fees or additional payments required.
Hassle-Free Delivery: DDP (Delivered Duty Paid) shipping supported in most regions.
Please enter your country in the shopping cart to confirm availability.
Shipping Time: Estimated 12–18 days.
- Continuous Power
- 400W
- Assisted speed · supported in testing
- 45km/h
- Battery
- 300Wh
- Estimated Range
- 72km
- Recovery
- 240W
High power and acceleration
Built for torque. The QR-E PRO-MAX delivers stronger acceleration and hill-climbing pull — the right choice for heavier bikes and steeper routes, without changing the assisted-speed range.
No noise
Active energy recovery
Aluminum alloy frame
Easy installation
The battery is the same size and weight as a water bottle
Same as the original balance of the bike. Maximize the joy of cycling.
Weight: 620g
QR-E PRO MAX size: 85 × 70 × 50mm
H70 weight: 1.5kg
Fix the motor with 2 M5 anti-rust screws
The first installation and adjustment time is estimated to be completed in 5–10 minutes. Comes with a variety of installation tools, compatible with most bicycles.
Whether it’s road, mountain, folding, or small-wheel bikes
The QR-E kit can be naturally integrated into the style of the bicycle without being obtrusive.
Polymer Rubber Friction Stickers
The motor automatically synchronizes with the tire speed
No resistance.
S-2 control switch
PRO or PRO-MAX?
Same assisted-speed range, same H70 battery, same hybrid clutch. The difference is power and fit: PRO is the lightest, most hidden build for road bikes; PRO-MAX is the all-rounder that pulls harder on climbs and fits more places on the frame.
Power & performance
- Continuous power The output the motor sustains, not a short peak.
- 320W
- 400W +80 W
- Regenerative braking Active energy recovery during deceleration.
- 200W
- 240W +40 W
- Climbing
- Flat to rolling routes
- Stronger on steep, sustained climbs
- Assisted speed Motor supports up to 28 mph in testing, with pedalling assistance. Ride within local limits.
- 45km/h
- 45km/h
- Riding modes
- ECO / Sports
- ECO / Sports
- Clutch
- Electronic + mechanical
- Electronic + mechanical
- Rotation
- Two-way
- Two-way
Fit & installation
- Best suited to Where each version performs best.
- Road bikes and light builds
- Folding, mountain and heavier bikes
- Compatible bikes Both versions fit all of these.
- Road, city, folding, off-road on road tyres
- Road, city, folding, off-road on road tyres
- Motor weight Drive unit only, battery not included.
- 520g
- 620g
- Installation space required Clear area needed near the rear tyre.
- 6 × 4cm
- 7 × 5cm
- Mounting positions PRO-MAX needs slightly more room but accepts more places on the frame.
- Smallest footprint — fits the most hidden spots
- Bottom-mounted or inverted — more positions
- Mounting
- 2 × M5 anti-rust screws
- 2 × M5 anti-rust screws
- First install time
- 5–10 min
- 5–10 min
Battery & range — H70 kit
- Battery energy
- 300Wh
- 300Wh
- Estimated range Assisted riding, customer-feedback average.
- 72km
- 72km
- Battery weight
- 1.5kg
- 1.5kg
- Battery size
- 73 × 230mm
- 73 × 230mm
- Charger
- 37 V 2 A
- 37 V 2 A
Consumables
- Friction layer refill The two versions take different friction layers — order the one that matches.
- QR-E MUTE / PRO · 10 pcs
- QR-E PRO-MAX · 6 pcs
- In the box
- Drive, H70, charger, S-2 switch, tool, 2 friction layers
- Drive, H70, charger, S-2 switch, tool, 2 friction layers
- M-Flex240WDIY setups, bring your own 36 V battery
- MUTE250WTypical city commuting
- PRO320WRoad and city bikes, flat to rolling routes
- PRO-MAX400WSteeper routes, heavier bikes, longer trips
MUTE and M-Flex are shown for family context and are not part of this comparison. M-Flex has no regenerative braking; every other version does.
Assisted-speed figures describe motor capability measured under test conditions with pedalling assistance — not a target speed, and not a promise of real-world performance. Range figures are real-world averages reported by customers; actual results vary with rider weight, tyre type, gradient, wind and battery condition. Many regions cap assisted speed on public roads — always ride within the limits that apply where you are. Power figures are continuous output, not peak.
Installation video
QIROLL QR-E E-Bike Kit installation
Shipping and compatibility
Express delivery
We use express delivery to reach most parts of the world. Estimated delivery 12–18 days worldwide. DDP shipping is supported in most regions; minor customs duties may apply in certain regions. Contact us if you need to confirm delivery to your location.
Special bicycles
For some special bicycles, please send us photos of the bicycle before ordering. For US and EU customers, VAT service is provided; no additional VAT payment is required.
In the box
1. QR-E PRO-MAX
Friction drive system
2. H70 battery
33V 300Wh bottle battery
3. DC charger
37V 2A
4. S-2 control switch
5. Tool
6. Friction × 2
Electronic clutch technology
The electronic clutch is a virtual clutch. The way of working is that the motor is not separated from the tire (not through mechanical parts), and electronics are used to eliminate the resistance of the motor. Manually separate the motor from the tire only when the booster is not in use.
Electric Clutch
Qiroll’s electronic clutch technology ensures a very stable drive. It comes into contact with the tire without resistance and can enter the operating state quickly and steadily.
Mechanical Clutch
The adjustment knob separates the motor from the tire when the battery is completely depleted or needs to be self-riding.
Flexible use
The booster can be easily removed when it is not in use. With electronic clutch technology, installation and adjustment are very simple.
Reliability
The third generation of motors has a larger margin, and the motor life is also very long. In extreme cases, the internal controller actively cuts off the power to ensure safety.
Reliable system
QR-E components are designed for friction assist. After years of testing and market feedback, they are reliable, stable and easy to install.
Installed on real bikes
Real customer builds with the QR-E system.
Estimated delivery time 12–18 days
More customer builds
Explore more real-world QIROLL installations.
