How to Choose Hub Motor Power, Rated Speed and Torque for Low-Speed Wheeled Equipment

Shenzhen Jinhaixin Holdings Co., Ltd

2026-09-16

WINAMICS explains how to select brushless hub motor power, rated speed and torque for low-speed, high-torque wheeled equipment based on load, wheel diameter, grade and target vehicle speed.

Brushless hub motor selection for a low-speed wheeled vehicle based on load, wheel diameter, grade and target speed

For low-speed wheeled equipment, selecting a brushless hub motor is not simply a matter of choosing a higher power rating. The motor’s power, rated speed and torque need to work together with the vehicle load, wheel diameter, target travel speed, grade requirement and real operating conditions. A balanced selection helps equipment start reliably, run smoothly at low speed and maintain suitable performance during continuous operation.

WINAMICS supports OEM and ODM equipment projects with brushless hub motor selection, motor and controller matching, prototype testing and customized electric drive solutions for applications such as electric carts, trolleys, AGVs, mobile robots, amusement vehicles, wheelchairs and specialized mobile equipment.

Start with the actual vehicle operating conditions

A low-speed vehicle may require high starting force even when its target speed is modest. This is especially relevant for equipment that carries loads, uses larger wheels, travels on uneven ground, starts and stops frequently, or must climb grades. The most reliable hub motor selection begins with a clear description of the application rather than a single motor parameter.

Vehicle load

Consider the vehicle weight, payload and any changing load conditions. Total moving mass directly affects required starting and climbing torque.

Wheel diameter

Wheel size links motor rotational speed to vehicle speed. A larger wheel generally needs more wheel torque to produce the same driving force.

Grade and surface

Slopes, ramps, floor condition, rolling resistance and outdoor terrain can substantially change the torque demand.

Duty cycle

Continuous running time, stop-start frequency, ambient conditions and loading duration affect motor heating and controller requirements.

Understand the relationship between speed, torque and power

For a direct-drive brushless hub motor, these parameters should be evaluated as one system. Rated speed defines the intended motor operating range, torque provides the rotational force at the wheel, and power represents the rate at which the motor can deliver mechanical work. Selecting one value without checking the others can lead to poor starting performance, unsuitable travel speed or excessive temperature rise.

Selection parameter	What it influences	What to verify
Rated speed	Vehicle travel speed at the selected wheel diameter	Target speed, wheel circumference, voltage and speed-control range
Rated torque	Steady driving ability under normal load	Vehicle mass, rolling resistance, number of drive wheels and operating surface
Starting and climbing torque	Launch, acceleration and gradeability	Maximum load, slope, start-stop frequency and controller current capability
Motor power	Ability to sustain the required torque at the intended speed	Continuous duty, thermal conditions, voltage and expected load profile

How to determine the appropriate rated speed

A hub motor rotates with the wheel, so motor speed is directly related to wheel diameter and target vehicle speed. For the same target travel speed, a smaller wheel requires a higher motor rotational speed, while a larger wheel requires a lower rotational speed. Voltage and controller settings also affect the usable speed range.

Selection note: Do not choose rated speed based only on an unloaded vehicle. Check the desired speed at the expected operating load, and consider whether the equipment needs controlled low-speed movement, forward and reverse operation, or different speed modes.

For applications such as AGVs, service robots, electric trolleys and material handling carts, stable low-speed control may be as important as maximum vehicle speed. In these cases, motor selection should be coordinated with the controller and the intended control method.

Why torque should be checked before increasing motor power

Low-speed wheeled equipment often needs torque first: enough torque to overcome rolling resistance, start from rest, move the required load and climb the expected grade. A higher power motor is not automatically the correct answer if its speed range, wheel size, controller current or installation structure does not match the vehicle.

Starting torque: needed when the vehicle begins moving from a stationary position, especially with payload or on an incline.
Continuous torque: needed to maintain normal movement under typical operating load.
Peak operating demand: may occur during acceleration, ramp climbing, turning resistance or short periods of heavier load.
Wheel torque distribution: depends on the number of driven wheels and how the vehicle load is distributed across them.

A properly selected low-speed high-torque hub motor should be assessed against the complete drive condition, including the wheel, tire, axle arrangement, vehicle structure and controller current settings.

Use motor power as a system-level selection value

Motor power is related to torque and rotational speed. In practical equipment design, it should be selected with enough margin for the planned operating conditions, but without overlooking thermal performance, battery voltage, controller capability and mechanical integration. A motor that performs well in a brief unloaded test may not be suitable for repeated loaded operation.

For load-carrying carts

Focus on loaded starts, total vehicle mass, wheel diameter, ramp use and the expected duration of continuous operation.

For robots and AGVs

Consider precise low-speed control, direction changes, duty cycle, wheel traction and coordinated motor-controller behavior.

For amusement vehicles

Check passenger or vehicle load, frequent starts and stops, intended speed range, steering conditions and continuous-use temperature rise.

Controller matching is part of hub motor selection

The controller affects how a brushless hub motor starts, accelerates, reverses, regulates speed and responds under load. Motor and controller parameters should be evaluated together, particularly for low-speed high-torque applications where starting current and smooth control are important.

Key motor-controller matching points

System voltage and compatible operating range
Required current capability for starting and loaded operation
Target speed range and speed-control requirements
Forward and reverse control requirements
Motor wiring, connector and harness interface requirements
Required braking or other equipment-specific control functions

Validate the selection under representative conditions

Selection calculations and preliminary specifications provide a starting point, but sample testing is valuable before mass production. The test plan should reflect the equipment’s intended use and identify whether the selected motor, wheel structure and controller configuration operate appropriately together.

Confirm the application inputs: vehicle mass, payload, wheel size, target speed, grade, voltage, installation space and operating environment.
Define the drive configuration: number of drive wheels, motor installation position, axle structure, tire requirement and controller interface.
Evaluate prototype performance: test starting behavior, forward and reverse operation, speed control and loaded movement.
Check continuous operation: assess load performance, temperature rise, noise, vibration and repeated operating cycles as relevant to the application.
Refine for production: confirm custom parameters, drawings, harnesses, installation details and the motor-controller solution for the equipment project.

Information to prepare for hub motor sizing

Providing complete application information helps make motor selection more relevant to the actual vehicle. The following checklist can be used when discussing a custom hub motor or integrated electric drive solution.

Vehicle weight and payload Target vehicle speed Wheel diameter and tire type Maximum grade or ramp Battery or system voltage Number of drive wheels Duty cycle and environment Installation dimensions Control and braking requirements

Support for customized low-speed electric drive projects

WINAMICS develops brushless hub motor and motor-controller solutions around the real operating requirements of wheeled equipment. Available customization considerations can include voltage, power, rated speed, torque, wheel size, tire material, axle structure, installation dimensions, wiring interfaces, braking structure and applicable protection requirements.

For an OEM or ODM project, share the vehicle load, target speed, wheel dimensions, grade requirement, operating environment and installation layout. This provides a practical basis for motor sizing, controller matching, prototype development and performance validation before batch production.