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2021 CYC X1 Stealth 36-72v 1500W with ASI BAC855 controller.
The CYC X1 Stealth mid-drive motor is a high-end/high-performance ebike conversion system that is the creation of CYC Motors in Hong Kong. These guys know what they are doing. They created this bad boy as the stealthy baby brother of the X1 Pro but it is still one of the most powerful motors available.
This motor preserves a perfect chain-line on any bike and tucks up high off the ground even on modern mountain bikes with a curved downtube. With its torque sensing and cadence sensing bottom bracket, it delivers power at the cadence you choose and senses when you crank up your effort and delivers more power on demand.
This motor is very versatile, fitting 95% of frame types including carbon frames. It can be set up as a class 1, class 2, or class 3 ebike from 350 to 750 watts. Off-rode modes go from 750-2,000 watts (depending on battery).
It comes with everything you need except the battery and we have those in 52v and 72v at 50 amps and from 300 watt hours to over 1000 watt hours.
- 750-2000 Watt 9,000RPM Motor
- Motor-reduction assembly
- Integrated programmable ASI BAC855 Controller (36-72V 50A)
- Torque-sensing Bottom bracket and freewheel crankset
- Waterproof wire harness
- Spacer for 68mm/73mm bottom bracket (For 68/73/83mm version)
- 500C color display 36-52V (upgrade to 750C for 72V)
- Thumb Throttle
- User manual
- 219H Golden KMC Chain and chainrings
For lights powered from the main battery, you should consider the Roxim Light Set. It can take voltages from 6v-90v and can be wired directly into the main battery. A single switch on the headlight turns the headlight and taillight on/off.
For a great 1x drivetrain the ebike rated Box Two and Box Three drivetrains are both durable and affordable. With all of the power this motor can deliver, you will still wear out the higher (smaller) gears on the rear sprocket. Fortunately, Electrify Bike Co. has arranged with Box to sell these as a set of 4 sprockets for just $20 so you can just change them out when they start to slip.
Stealth motors have proven definitely worth the wait.
Note: Due to manufacturing supply chain issues total delivery time is 4-6 weeks for all new orders. Thank you for your patience.
The X1 Stealth is the all new lightweight mid drive conversion system. With up to 1500W of power output, a small form factor, and a more silent performance, this is the ideal system for riders wanting a stealthy setup.
The X1 Stealth is complete with:
- torque sensing capabilities
- fully customizable mobile app
- Range of bottom bracket sizes
- High clearance
- Fits all frame types including carbon
- 2 rider modes (e.g., street, off-road)
- 9 assist levels
Max. RPM (at Crank)
Max. Rated Power
Max. Torque (at Crank)
Weight (Motor & controller)
Total wgt. w/crankset & BB
Crank Arm Length
BSA Threaded Frames
No-load Motor kV
Efficiency (at 2N.m.)
Rated RPM (at 2 N.m.)
First stage reduction
Overall reduction ratio
from motor to crank
36-72 DCV (nominal) (10-20s Batteries)
165mm or 170mm
190mm (208mm for fat bikes)
Hall & temperature sensor
11/53 option with 32T bike chainring
11/63 option with 38T bike chainring
500c or 750c APT display
Thumb, half-twist, or full throttle
Waterproof wire (Julet connector)
BSA threaded or pressfit option with additional spacers:
3, 5, & 7mm spacers for BSA threaded
2x 2mm spacers for pressfit
Integrated torque & cadence sensor
Magnetic sensor for all brakes (optional)
34.5mm bottom bracket diameter
68mm, 73mm, & 83mm width
41 bottom bracket diameter
N45UH (>180 °C)
Black epoxy potted stator
1:6 low noise brass planetary gear
Hardened steel sun & ring gear
CYC MOTOR (BAC) MOBILE APP FOR ASI BAC CONTROLLERSThe CYC MOTOR (BAC) app is the X1 PRO and the X1 Stealth's navigation system. This is where you will customize your experience & monitor your performance.
The app is connected to your controller via Bluetooth & will allow you to set up your system & change parameters according to your preference.
The CYC MOTOR (BAC) app allows you to do multiple things:
- Set up your desired power output's for 2 different modes
- Customize your parameters for pedal assist, throttle performance, & gear preferences
- Configure your torque sensor
- Monitor your performance
- Set up your e-bike battery & peripherals
- See warnings & clear errors
If you have a BAC855 or BAC2000 controller for your X1 PRO or X1 Stealth, then this app is needed to set up a few things to get started such as your regions legal limits, your battery voltage, & wheel diameter. You will also need the app to clear any warnings or errors that may occur.
X1 Stealth Documentation
Mobile App Guide
APT 500c Display User Manual
APT 750c Display User Manual
Speed Sensor Installation Guide
Brake Sensor Installation Guide
(Check clearances on bike)
(print actual size or 100%)
X1 STEALTH right side
X1 STEALTH left side