Introduction to the Ultra intelligent assist system
Ultra Ebike assist system is an intelligent assist system that provides the Appropriate power assist level based on the speed, acceleration, the slope of the road, and the user preference assist level set in the App. It will provide power automatically when you are pedaling. The motor will not assist until the speed reaches 5km/h. It will deliver power when it senses acceleration and decrease the when braking. The system will also increase the power when on an incline and shut down the motor when going downhill.

The 5 assist modes are as follows;
*Manual mode:
The most often used mode. The users can set their preferred assist grade from 0 to 99%. 0 stands for no assist while 99 stands for the strongest assist. After setting the assist grade, the wheel will assist automatically.

*Climbing mode:
The wheel provides a certain assist grade only if the road is uphill and above a certain user set slope angle. The assist grade and the slope angle can be set in the App. For example, when you set 2 degrees and 80 assist grade, the wheel can give you 80% assist grade when you are on a road with slope angle above 2 degrees.

*Commute mode: Under this mode, the wheel will provide fairly strong assist power all the time. The output curve of the assist grade is as shown on the on-screen graph. It is similar to an assist grade of 60% in the manual mode.

* Leisure mode:
The assist power output is as the illustrated curve shown on main screen. The assist power output will increase and decrease in 10 min cycles to allow for a leisurely cycle with moderate exercise.

*Exercise mode:
This mode has a low assist output to allow for a good exercise routine with occasional assistance.

Note: We will occasionally optimize the algorithms and publish the new firmware. Ultra intelligent assist system can be upgraded via the App.

Ultra Ebike smart assist system is a unique assist system developed by Ultra and our tech partners. The user sets the desired assist level and the kit will provide the corresponding power automatically according to varying road parameters and various user preferences. For example: Setting the assist level to 40%, which means that to maintain a certain speed, the motor will provide 40% of the power, and the rider needs to provide 60% of the power. When the rider decreases the pedaling power, the system will ask the motor to slow down and the speed of the bike will be reduced accordingly; when the rider increases the pedaling power, the system can immediately sense it, increase the assist power and increase the speed. So if you want to ride easily, you can set the assist level to 90%, then you just need to pedal lightly; if you have enough physical strength, we can adjust the assist level to 30%, so that the motor provides less part of the power, then the bike is 70% driven by human power.

The system will automatically regulate power when braking. The kit can sense braking through various parameters such as deceleration, angular velocity, current, voltage, and riding speed. It can sense braking and shut down the motor within 10ms (0.01 second). 

The system will not shut down the motor completely when you squeeze the brake slightly. It can sense the slight change of the speed, but it will not shut down the motor because it thinks that you just want to slow. If you squeeze the brake with more intent and want to stop, the system will sense this and cut the power completely.

Ultra wheel has a built-in six-axis gyroscope, which can sense the slope angle of the terrain. In order for it to detect the slope accurately,, you must calibrate the gyroscope angle on level ground first.

How the gyroscope works: The purpose of calibrating the gyroscope angle is to provide the gyroscope with a horizontal reference, so it can detect a slope. If the gyroscope is calibrated on an incline, the gyroscope will regard the incline as a horizontal, so the motor will provide incorrect assistance; Therefore, you must calibrate the gyroscope on level horizontal ground to insure correct and accurate power delivery.

You can buy a bottle conversion bracket online from the Ultra shop.

You can adjust the clearance between the hub and the fork by adding or removing the spacer washers on both sides. For example, if the brake caliper makes contact with the hub or the spokes, then remove axle spacer washers on caliper side to gain the clearance to avoid the collision. Add washers to gain more space the other side if required. Experiment with spacers until wheel spins freely and is center aligned with brake callipers.
There are two brake caliper mounting points on the fork, loosen these two bolts and move the caliper right or left to adjust to obtain a proper clearance, and then tighten the bolts to fix the caliper.

Open the App and allow all the permissions those the App asks for.
Now tap the magnify glass icon on the right top of the App to search the Bluetooth address. Select the right address of your kit in the list to connect.

*Note: Please connect the kit in the App, don’t connect it in the operation system of the phone. You won’t need to input any pin numbers to connect to the Ultra App. Please make sure all permissions are allowed and the kit is not connected with other devices. The kit can connect to only one device at the same time.

Ultra Ebike assist system is a unique to any other systems. The slope of the terrain is a critical factor of how the system calculates the power that you need. The Gyroscope can measure the slope, but it needs to know what 0-degree ground is. You need to calibrate the Gyro angle to be 0 on a level ground as per the instructions in ‘Gyro Angle Calibration’ in the App. This will enable the gyroscope to tell how many degrees incline you are on and ask the system to provide the Appropriate assist power. If you do not calibrate the Gyroscope, you may get incorrect or no assistance from the motor.

Make sure the battery is not dead;

  1. Make sure the kit is not connected to any other Bluetooth devices (phone or display)… Disconnect it if there are other connected devices;
  2. Do not connect the bike via the operation system of the phone, connect it in the Ultra App;
  3. Make sure the Bluetooth of the phone is switched on and the GPS or location service is switched on in the phone system;
  4. Make sure that you have allowed all the permissions those the App asks when you first open the App. If you have not allowed the permissions, please uninstall and reinstall the App, when the App asks the permissions again, please allow them;
  5. Please try another mobile phone if the phone is too old to connect.

Please follow the steps as below to solve the problem:

  1. Check whether the wheel, the controller, etc. are correctly installed, please install them according to the user manual.
  2. Tap “restore factory” in the setting page of the App;
  3. Re-calibrate the gyroscope angle in the App.

Please follow the steps as below to solve the problem:

  1. Check whether the wheel, the controller, etc. are correctly installed, please install them according to the user manual.
  2. Tap “restore factory” in the setting page of the App;
  3. Re-calibrate the gyroscope angle in the App.
No, you don’t have to connect the kit with the App when you are riding. The assist system is written in the controller, not in the App. But before the first time you use the kit, you must calibrate the gyro angle for the bike. You can set the assist grade in the App and put your phone in your pocket. The kit will provide Appropriate assist power automatically.

The gyroscope is not calibrated correctly. Stand the bike upright on level horizontal ground, and then calibrate the gyroscope through the App or Bluetooth display. This is so that the gyroscope can sense the correct slope gradients and provide Appropriate assist power.

Please check the points below if there is no assist power

  1. Please check that the battery is charged;
  2. Please check that the assist grade is not set at 0;
  3. Please check that the assist mode is not climbing mode with a high slope value;
  4. Please check that the kit is mounted correctly and the gyroscope is calibrated correctly before the first time you use it;
  5. Please check that you have not set a very low value for “speed limit” in the setting;
  6. Please check that the kit is not locked in the App.

The climbing mode means that it only assists on uphill roads, and therefore will not assist on level roads or downhill roads. Rider can use this feature to save battery power or just make it easier to climb. Under climbing mode, the kit provides a certain assist grade only if the road is uphill with a slope angle that is above a certain set value. The assist grade and the slope angle can be set in the App. For example, when you set 2 degrees and 80 assist grade, the wheel can give you 80 assist grade when you are on the road with slope angle above 2 degrees.

When the battery level is lower than 20- 30%, the assist power would be weak or unstable to avoid battery over discharge. So it is normal if the motor does not assist when the battery level is 10 – 20%.

Top-up your charge whenever possible. Battery is hAppier with charge than without.

There are several reasons why the assistance is weak or sometimes no assistance:

  1. Check that the wheel is installed correctly, please refer to the instruction manuals and install it correctly according to the instructions. If the installation is not correct, the assistance may be unstable;
  2. Adjust the assist mode. If the assist level is set to low, the assist may be absent from time to time. Please increase the assist level;
  3. The wheel is not tightened, please tighten the wheel nuts to avoid danger;
  4. The angle of the gyroscope is incorrect, please place the bike on level ground and re-calibrate the gyroscope;
  5. If you are in climbing mode, set a lower value for the slope. The motor will only engage when it reaches the set slope value.
  1. The abnormal power assist may be caused by incorrect gyro calibration. Go to ‘Calibrate’ in App ‘Settings’ menu and calibrate the angle of the gyroscope;
  2. Check if the Ultra battery power is too low (below 30%). Low battery charge will cause occasional failure when assisting to prevent from over discharge; If so, recharge the battery.
  3. Test the battery capacity; Charge the battery when it is completely used up. The charging time of the battery from a fully discharged battery is about 110 mins. If there is a significant difference in charge time, the battery has reached end of its lifespan and may need replacing.

Please check;

  1. Check for friction between the motor hub and the front fork. Please adjust the clearance by adding or removing washers between hub and the front fork;
  2. General bike maintenance: Check if there is pad friction on the disc brake. Adjust the position of the disc brake caliper to avoid the friction.
  3. General bike maintenance: Check if the spoke caps are damaged or if any spokes are loose. If the spoke caps loosen, you will need to remove the tube and tire to replace or tighten the spoke caps;
  4. Check if the brake disc attaching screws are too long and touch against the hub inside. You can remove the disc and the screws to try if there is still a noise or not. If the disc brake screws are too long, please replace them with shorter disc brake screws.
The motor is not a regenerative motor. Ultra wheel uses a clutch which creates no resistance, making it as easy as riding a normal bike when the battery is dead or if the rider chooses to switch off assistance and ride normally.
The power of the motor is 250 watts, under pure electric driven mode (driven by throttle), the kit can climb a maximum slope of about 12% (about 7degrees) without human pedal power. If the slope is above 12%, you’d need to use pedal and assist power together.
Yes. You can either switch the kit off or even remove the battery or set the kit to 0 assistance and ride the bike as you normally would.

Yes! You can ride in the rain.

Ultra Ebike wheel’s motor has SKF waterproof bearings, the controller is treated with waterproof coatings, and the battery is enclosed in a heat sealed casing and treated with waterproof coating. Therefore, the waterproof grade is P65. You don’t need to worry about water ingress when riding in the rain, but we recommend that you don’t store the bike in damp environments for sustained periods of time and wipe the kit dry when you’ve completed your ride to avoid the vapor penetrating into the motor.

The version of the App is dated, please update to the latest version of App.

When you tap the lock icon in the App, the motor will be disabled. The power assist will not work, you can still ride the bike but when the bike moves, it will sound an annoying loud alarm.

After you connect the kit for the first time, the App will pop up a text input field to modify the wheel name. You can also modify it by the two methods;

  1. Tap the name of the wheel on the main view of the App to edit the name;
  2. 2. Find the name on the setting page and tap on it to modify.
Please tap “Restore Factory” in the setting page of the App
Tap the “Firmware Upgrade” in the setting page of the App to update the firmware.

This is mainly caused by an unstable connection between the kit and App:

  1. Make sure the bike is near your phone, if it is distanced, the Bluetooth connection may be interrupted;
  2. Quit and re-launch the App and connect the kit again.
  3. Switch the main battery ‘off’ then ‘on’ to reset the system.

Fault 01: Over-current or sudden breakdown of MOS.

Reason: Driving circuit fault or over current leads to MOS short.


  1. Disconnect and reconnect the motor cable, and restart the kit in the App.
  2. If the Fault 01 is still there after restarting, and the motor is stuck when cranked in reverse, this means the MOS has failed. The controller may need replacing.


Fault 02: The motor is stuck.

Reason: Fault 02 usually occurs when the wheel is stopped by force or other components and objects, such as sudden brake.

Solution: Clear the object that stops the motor from rotating and restart the kit in the App.

Fault 08: Hall Fault.

Reason: The connection between the controller and the motor has poor contact.

Solution: Reconnect the cable between the motor and the controller. Usually, Fault 08 is temporary.


Fault 10: Gyroscope fault.

Reason: Water or moisture has entered the controller causing problems with the gyroscope. This happens very rarely.

Solution: Dry the controller and leave it at room temperature or a few days.


Fault 20: 24C02 electronic device failure.

Reason: Water or moisture has entered the controller. This happens rarely.

Solution: Dry the controller and leave it at room temperature or a few days.


Fault 40: Hall is abnormal.


  1. The motor wire is not connected well or the motor wire is broken;
  2. The motor’s Hall is burnt out due to water ingress or motor burnout;
  3. The internal magnet of the motor rubs the circuit.



  1. Check if the cables between the motor and controller are connected well, and check that the cable connect is plugged in deeply enough to reach the mark line. If not please disconnect and reconnect the connectors to the mark line and then restart the kit in the App settings.
  2. Check if the motor wire is broken. If the wire on the motor side is broken, the motor needs to be replaced.

*Note: Fault codes can be combined. For example: Fault 48 stands for both Fault 08 and Fault 40; Fault 0A stands for both Fault 02 and Fault 08.

Please tap “Restore Factory” in the App setting page and try again.

Mileage: Perimeter of the wheel and revolutions count = mileage

Riding time: Time accumulation when the speed is more than 0;

Calories consumed by riding: Calculate based on bike and rider weight, load, assist settings and a number of other parameters.

Average speed: The total mileage divided by the ride time.

You can judge the if the capacity of the battery is normal or not by the charging time of the battery. Drain the battery and check the charging time: The charging time of the Ultra Ebike battery is about 3 hours. If the charging time is far from above, then there is something wrong with the battery.
The ideal working environment temperature of lithium battery is 25℃, under this temperature the lithium battery has the highest efficiency. The normal charging working temperature is 0℃-60℃, and the normal discharging working temperature is -20℃-60℃. However, the performance of the lithium battery will decrease when the temperature is lower than 0℃, and the discharge capacity will be reduced accordingly. The working temperature of Ultra wheel’s lithium battery is controlled between 0°C and 40°C. The BMS will stop power supply after the battery temperature exceeds 70°C to ensure the safety of the battery.

Ultra Ebike kits use EV18650 lithium-ion battery cells of class A quality. Working with our own BMS system, the lifetime of the battery is high. 75% ~80% charge capacity is retained after 1,000 cycles. So with normal use, it can last up to 5 years.

*Note: The definition of one cycle is that charge the battery from 0 to 100% and discharge it fully. For example, if you charge the battery from the 0 to 50% and discharge it to 0, that is 0.5 cycle.

Lithium-ion batteries are different from traditional lead-acid batteries. Lithium-ion batteries have no memory effect. You don’t have to wait until the battery is drained before charging. The indicator light of the charger will turn green when the battery is fully charged. If you don’t ride the bike for a long time, we recommend that you charge the battery at least once in every 3 months to avoid the battery having a low voltage, low voltage will have negative influence to the battery’s performance.

The wireless display with throttle integrates the display and a thumb throttle together. It displays the speed and allows you to set the parameters of the kit, and can be used as a throttle to control the power delivery. The display connects to the kit via Bluetooth. There is no cable between the display and the kit. The display can replace the smart phone App for the fundamental functions; search and connect the kit, calibrate the gyroscope, set the assist grade, and display live cycling data. The kit can not connect to the display and the mobile App at the same time. For example when the phone is connected, you need to quit the App or switch off the Bluetooth of the phone before you connect it to the display.

NOTE: The PAS device is not compatible with the throttle device, so this device should be used on private land only.


  1. Quit the App, turn off or disconnect the Bluetooth connection on your phone before you switch the Bluetooth display on. The wheel cannot connect to more than one device at the same time;
  2. Press the power button of the Bluetooth display to turn it on. Then press the power button three times repeatedly. The display will search for the Bluetooth address of the Ultra Ebike kits nearby;
  3. After the display finishes the search, press the up and down keys to select the right address of your kit and press the power button to connect.
Ultra Ebike Wheel cannot be connected to both the mobile phone App and the Bluetooth display at the same time, it can only connect to a single device at the same time. When you connect the Bluetooth display, you can no longer connect to the mobile phone. One of the devices must be disconnected before the other device is connected.

Battery capacity: 1200mAh

Standby time: more than 12 months

Working time: 100 hours

Charging time: 3 hours

When the circle icon on the right top of the screen flashes, it indicates that the display is running out of power and the screen will go dim. When the display is charging, the light in the background glows red, and the light will turn green if the display is fully charged.

*Note: The display cannot be used during charging.

There are 2 ways to clear the current mileage in the App (The mileage cannot be cleared directly by the display);

  1. Tap and hold the value of speed or current mileage on the main page of the App to clear;
  2. Tap “Current record” in the setting page of the App and then tap “clear” on top right to clear.

This problem may be caused by the unstable connection between the Bluetooth display and the kit. Please connect the kit with the App to see if the mileage can be displayed.

  1. If the App does not have mileage displayed, try “Restore Factory” in the setting page;
  2. If the App displays the mileage, it means there is a problem with the Bluetooth connection of the Bluetooth display. Try to switch off the Bluetooth display and switch on it again and reconnect it with the kit.