Sotion H02/H16, QS260, and QS273 Thermal Performance

Sotion H02 and H16 Motors for ONYX RCR

The Sotion H02 and H16 are high-performance hub motors that have also appeared with QSMOTOR branding. They share the same basic motor design, but the H02 is designed for a spoked wheel, while the H16 comes with a 16-inch cast wheel.

The primary reason to consider these larger motors is greater thermal capacity. All four motors in this comparison have demonstrated excellent thermal performance in practical use, including mountain climbing, racing, and sustained high-power riding.

Larger motors generally provide more thermal reserve because they contain more material capable of absorbing heat. However, motor size is only one factor. Winding design, efficiency, magnet construction, and cooling also influence sustained performance.

Performance is the second consideration. The Sotion H02/H16 and QS273 V4 Mag have approximately 350 Nm of reported maximum torque, but certain Sotion configurations can spin significantly faster.

At 72V, the QS273 V4 Mag reaches approximately 1,380 RPM, while certain Sotion H02/H16 configurations can reach 2,000-2,500 RPM.

That gives the Sotion greater potential top speed, provided the battery, controller, and motor configuration can support it.

This article explains the thermal and performance characteristics of the Sotion H02/H16, QS260 V4 Mag, QS273 V4 Mag, and QS260 V4 155mm 6AWG.

ONYX 80V Warranty Warning

Installing an aftermarket Sotion or QS motor on your ONYX 80V voids the factory warranty, including the one-year battery warranty. ONYX Motors is not responsible for supporting aftermarket motors, installation problems, or damage caused by these modifications. Do not contact ONYX Motors for assistance with these upgrades. You are responsible for installation, compatibility, and any resulting issues.

ONYX RCR Fitment and Swingarm Safety

Both Sotion motors have a 200 mm mounting width, but installation depends on which ONYX you own.

ONYX RCR 72V: The original swingarm is too narrow for these motors. Installing either the H02 or H16 requires a compatible 200 mm swingarm.

ONYX RCR 80V: The factory swingarm accommodates the 200 mm motor width. However, approximately 2 mm of filing may be necessary at the axle slots to accommodate the motor axle.

Swingarm Safety Warning: Read the Caution page before installing an aftermarket motor. Never use flat-plate swingarms, whether they are 150 mm or 200 mm wide. This includes the flat-plate swingarm designs found on first-generation Huck Rebels. Do not use these swingarms for an ONYX motor conversion.

Recommended Suppliers

These are not standard motor configurations available through AliExpress or Alibaba. Levin Acierto and Henry Strange have spent months customizing, configuring, and testing these motors specifically for high-performance ONYX builds.

• Sotion H02/H16: Levin Acierto at LEVUP.
• QS motors: Henry Strange at SDF Customs.
• Custom 72V and 80V swingarms: Stephen Williams at Captive Products.

The motor configurations are not yet listed for sale on the suppliers’ websites, but you can contact Levin or Henry directly.

Sotion H02/H16 vs QS260 and QS273 Motor Comparison

The following chart compares the Sotion H02/H16, QS260 V4 Mag, QS273 V4 Mag, and QS260 V4 155mm 6AWG.

Some values are measured, while others are manufacturer specifications, configuration-dependent figures, or estimates. Values marked with an asterisk require confirmation for the specific motor configuration.

Specifications depend on the exact winding, controller, battery, and motor configuration. Peak power and maximum torque figures do not indicate what a motor can sustain continuously.

Thermal Capacity and Heat Management

All four motors have excellent thermal performance in practical use.

Their differences are primarily in physical size, thermal reserve, winding configuration, magnet dimensions, and operating characteristics.

Understanding thermal performance requires separating three concepts.

Thermal Capacity

Thermal capacity describes how much heat a motor can absorb for a given increase in temperature.

A motor with greater thermal capacity generally heats up more slowly when absorbing the same amount of heat.

Larger motors typically contain more copper, iron, and other materials that contribute to thermal mass.

This is one reason larger motors can be advantageous during sustained high-power operation.

However, thermal capacity does not determine how quickly heat escapes from the motor.

Heat Dissipation

Heat dissipation describes how effectively the motor transfers heat to its surroundings.

In an air-cooled hub motor, heat must travel from the windings and stator through the motor structure before reaching the surrounding air.

Heat transfer depends on several factors:

• Internal motor construction.
• Contact between internal components.
• Motor housing design.
• Surface area exposed to air.
• Ambient temperature.
• Airflow around the motor.

A motor with greater thermal mass may take longer to heat up, but it may also take longer to cool down.

Thermal capacity and heat dissipation are related, but they are not the same measurement.

Heat Generation

Heat generation describes how much electrical energy becomes heat instead of useful mechanical output.

Copper losses in the motor windings are particularly important.

As winding current increases, resistive heating increases approximately with the square of that current.

Doubling current through the same winding resistance produces approximately four times the resistive heating.

This explains why aggressive controller settings can increase motor temperatures rapidly.

Motor efficiency, winding resistance, magnetic losses, and operating RPM all affect total heat generation.

The best sustained thermal performance comes from a motor that generates manageable heat, absorbs temperature changes effectively, and dissipates heat efficiently.

Motor Magnets: Grades, Dimensions, and Temperature Ratings

Motor magnets are an important part of both performance and thermal reliability.

The comparison chart lists magnet heights of approximately 50 mm for the Sotion H02/H16, QS260 V4 Mag, and QS273 V4 Mag.

The QS260 V4 155mm 6AWG uses 40 mm magnets.

What Magnet Height Means

Magnet height describes one dimension of the permanent magnets used in the motor’s magnetic circuit.

In these hub motor configurations, the listed magnet height generally corresponds to the motor’s active magnetic width.

A larger active magnetic width can contribute to greater torque capability because more of the motor’s electromagnetic structure participates in producing torque.

However, magnet height alone does not determine maximum torque.

Other important factors include:

• Stator diameter.
• Winding configuration.
• Magnetic flux density.
• Magnet thickness and geometry.
• Air-gap dimensions.
• Phase current.
• Motor efficiency.

A motor with 50 mm magnets is not automatically more efficient or thermally superior to one with 40 mm magnets.

The complete motor design determines the result.

Understanding N35SH Magnets

N35SH is a neodymium magnet grade.

The designation contains two important parts.

N35: Identifies the magnet’s nominal maximum energy-product grade.

SH: Identifies a high-temperature classification commonly associated with a maximum recommended operating temperature of approximately 150°C.

That temperature rating describes the magnet material under specified conditions. It is not a universal temperature limit for the entire motor.

The actual resistance to demagnetization also depends on the magnet’s geometry, magnetic circuit, and operating conditions.

N35SH has been discussed as a possible magnet specification for these motors, but the exact magnet grades have not been confirmed for all four configurations.

It would be incorrect to assume every motor in the chart uses N35SH magnets without manufacturer or supplier confirmation.

Why Magnet Temperature Matters

Permanent magnets produce the magnetic field that allows the motor to generate torque.

As magnet temperature increases, magnetic strength generally decreases.

Some of that reduction is temporary and reverses when the magnets cool.

However, sufficiently high temperatures can cause irreversible demagnetization.

Permanent demagnetization can reduce motor torque capability and change its operating characteristics.

A magnet’s temperature rating is therefore an important reliability specification, especially during sustained high-power operation.

A motor can have excellent thermal capacity while still being limited by the temperature resistance of its magnets.

Motor Operating Temperatures and Thermal Limits

Motor temperature is one of the most important measurements when evaluating sustained performance.

However, a single temperature reading does not necessarily describe the temperature of every component inside the motor.

Winding Temperature

The copper windings generate heat when current flows through them.

Winding temperature is particularly important because excessive heat can damage electrical insulation.

The insulation system has its own temperature rating, which must be verified for the specific motor.

A motor’s allowable winding temperature cannot be determined from its magnet grade alone.

Magnet Temperature

The magnets are mounted in the rotor and may operate at a different temperature from the stator windings.

Their temperature depends on heat transfer within the motor and the conditions under which the motor is operating.

A winding temperature reading does not directly establish magnet temperature.

This distinction matters when evaluating the risk of demagnetization.

Controller-Reported Motor Temperature

A motor temperature sensor commonly measures temperature at or near the stator.

The controller displays or uses that reading to manage thermal protection.

However, the reading depends on:

• Sensor type.
• Sensor placement.
• Controller configuration.
• Sensor calibration.
• Thermal contact with the measured component.

A controller reading should not automatically be treated as the exact temperature of the magnets or the hottest point inside the windings.

Understanding 120°C and 150°C

Two temperature references are important to discuss.

These values should not be treated as automatic controller settings.

A motor with N35SH magnets may have a magnet material rating associated with 150°C, but that does not establish a safe 150°C winding temperature or controller-reported temperature.

Likewise, a 120°C sensor reading does not establish that every internal component is operating at 120°C.

Actual operating limits must come from the motor’s verified specifications and temperature sensor configuration.

Thermal Protection

Thermal protection is intended to reduce the risk of damage when motor temperature becomes excessive.

Depending on the controller, thermal protection may reduce current or power as temperature rises.

This can help prevent continued heat buildup during demanding operation.

For high-performance ONYX builds, motor temperature monitoring should be configured and tested before sustained high-power riding.

A larger motor does not eliminate the need for thermal protection.

Motor Performance: Torque, RPM, and Power

Thermal capacity determines how a motor responds to heat.

Torque, RPM, and power describe how the motor performs mechanical work.

These specifications are related, but each describes something different.

Torque

Torque is the twisting force produced by the motor.

Higher torque can improve acceleration and help overcome heavy loads when sufficient current is available.

The Sotion H02/H16 and QS273 V4 Mag both have reported maximum torque figures of approximately 350 Nm.

The QS260 V4 Mag has a measured maximum torque figure of 261 Nm, while the QS260 V4 155mm 6AWG is rated at approximately 220 Nm.

These are maximum torque figures, not continuous torque ratings.

The torque a motor can sustain depends on current, RPM, efficiency, and temperature.

RPM

RPM measures how quickly the motor rotates.

Because these are direct-drive hub motors, motor RPM corresponds to wheel RPM.

The Sotion H02/H16 has the highest listed maximum RPM range in this comparison.

This creates additional potential for high-speed operation.

However, a motor’s maximum RPM does not tell us how much torque it can produce at that speed.

It also does not establish its climbing efficiency.

A higher-RPM winding may require different current and controller settings than a lower-RPM winding.

Power

Mechanical power depends on torque and rotational speed.

A motor producing substantial torque at high RPM can deliver significant mechanical power.

However, peak power ratings do not establish sustained output.

The battery, controller, wiring, cooling, and motor temperature determine how much power the complete system can deliver.

A motor with a high peak power rating may still require thermal protection during extended operation.

RPM and Theoretical Road Speed

To understand why the Sotion’s RPM matters, consider a wheel with an approximately 23-inch outside diameter.

The following values show theoretical road speed at different wheel speeds.

These calculations assume the wheel maintains the listed RPM while traveling on the road.

They are not predictions of actual ONYX RCR top speed.

At higher speeds, aerodynamic drag increases substantially. The motor must produce enough power to overcome that drag while also accounting for rolling resistance and other losses.

A configuration capable of reaching 2,000-2,500 RPM without a significant load may not reach that speed while carrying a rider.

The value of the Sotion’s higher RPM is that it provides more potential operating range. Whether that range is usable depends on the complete electrical and mechanical setup.

Sotion H02 vs H16

The H02 and H16 share the same basic motor design. Their primary difference is the wheel configuration.

Sotion H02

The H02 is designed for a spoked wheel.

Its listed motor weight without a tire is approximately 44 lb.

A spoked-wheel configuration provides flexibility when selecting a compatible rim, although the final wheel dimensions and fitment must be checked.

Sotion H16

The H16 comes with a 16-inch cast wheel.

Its listed motor weight without a tire is approximately 50 lb.

One tire option is the Kenda K413 in size 130/70-16, with an approximate outside diameter of 23.2 inches.

Tire selection must account for swingarm clearance, wheel alignment, brake compatibility, and the overall installed diameter.

Neither motor should be selected based on wheel style alone. The final configuration must match the intended riding conditions and available installation space.

QS260 V4 Mag vs QS273 V4 Mag

The QS260 V4 Mag and QS273 V4 Mag are both 200 mm hub motors, but they have different performance characteristics.

The QS260 V4 Mag is lighter, with a listed weight of approximately 54 lb without a tire. Its measured maximum torque is 261 Nm, and its measured maximum efficiency is 91.7%.

The QS273 V4 Mag weighs approximately 60.6-61.7 lb without a tire. It has a reported maximum torque of 350 Nm and reaches approximately 1,380 RPM at 72V in its 2T configuration.

The QS273 is the stronger torque comparison for the Sotion H02/H16.

Its greater physical mass also suggests more thermal reserve, although motor mass alone does not establish continuous power capability.

The QS260 V4 Mag remains an excellent thermal performer with a lighter construction.

Both motors have demonstrated strong practical performance. Their differences should be evaluated in the context of motor size, winding configuration, and the complete electrical system.

QS260 V4 155mm 6AWG

The QS260 V4 155mm 6AWG is different from the other motors in this comparison because it uses a narrower 155 mm mounting width.

It has a listed weight of approximately 39 lb without a tire, making it the lightest option in the chart.

Its reported maximum torque is 220 Nm, with an estimated maximum RPM of approximately 850-1,000 at 72V for a 4T configuration.

Its 40 mm magnet height and smaller construction distinguish it from the larger 200 mm motors.

Although it has less physical thermal mass, that does not mean it performs poorly under demanding conditions.

It remains an excellent thermal performer in practical use.

The 155 mm mounting width makes it relevant to installations where a 200 mm motor is not the preferred option.

However, mounting width alone does not establish compatibility.

The ONYX RCR 72V installation requires fitment verification, while the ONYX RCR 80V requires an ONYX 260 plate.

Axle dimensions, brake alignment, wheel position, and available clearance must all be checked before installation.

Mountain Climbing and Racing

Mountain climbing and racing demonstrate why sustained thermal performance matters.

All four motors in this comparison have performed well in demanding real-world riding.

The important differences are how each motor produces torque, manages heat, and responds to sustained loads.

Mountain Climbing

Long, steep climbs require the motor to produce sustained torque.

At relatively low RPM, the motor may need substantial phase current to maintain that torque.

High current increases resistive heating in the windings.

At lower road speeds, airflow around the motor is also reduced.

This creates a demanding thermal environment.

A motor with greater thermal capacity can generally absorb more heat before experiencing the same temperature increase.

However, winding configuration and efficiency determine how much heat the motor generates while climbing.

This is why maximum torque and maximum RPM alone cannot establish climbing performance.

All four motors are capable performers. Larger motors generally provide additional thermal reserve, particularly during extended high-load operation.

Racing

Racing creates a different combination of thermal demands.

Repeated acceleration requires high torque and substantial current.

Sustained high-speed operation requires enough power to overcome aerodynamic drag and other resistance.

Both conditions generate heat.

Greater thermal capacity can help the motor absorb heat during repeated acceleration, while effective cooling becomes increasingly important during sustained operation.

The Sotion H02/H16 offers additional RPM potential, which may be useful in high-speed applications.

However, that advantage depends on the available electrical power and the motor’s ability to maintain useful torque at higher RPM.

Everyday Riding

For normal street riding, all four motors offer more thermal capability than many riders will regularly need.

The additional weight, installation requirements, and supporting electrical upgrades should be considered before selecting a larger motor.

A larger motor does not automatically improve every aspect of the riding experience.

Controller, Battery, and Installation Requirements

A high-performance hub motor is only one part of the system.

Installing a motor with greater power capability does not automatically increase the power delivered to the wheel.

The controller determines how current is supplied to the motor, while the battery must provide the required electrical power without exceeding its operating limits.

Before installation, verify:

• Battery voltage and discharge capability.
• Controller voltage and current limits.
• Motor winding and RPM characteristics.
• Phase-wire compatibility.
• Motor temperature monitoring.
• Axle dimensions and mounting width.
• Swingarm strength and axle retention.
• Brake alignment and compatibility.
• Wheel and tire clearance.

Controller settings must match the motor and the intended riding conditions.

Excessive current can overheat a motor even when that motor is physically larger than the original unit.

Temperature monitoring is particularly important when configuring a motor for sustained high-power operation.

Final Advice

The Sotion H02/H16, QS260 V4 Mag, QS273 V4 Mag, and QS260 V4 155mm 6AWG all offer excellent real-world thermal performance.

Their differences are primarily in thermal reserve, physical size, winding configuration, torque, RPM, and installation requirements.

Larger motors generally provide greater thermal capacity, but motor efficiency and heat dissipation remain equally important when evaluating sustained performance.

Magnet construction and temperature ratings also matter. A motor’s ability to absorb heat does not eliminate the operating limits of its magnets, windings, or insulation.

The Sotion H02/H16 adds a substantial RPM advantage over the QS273 V4 Mag while offering a similar reported maximum torque figure.

However, higher RPM does not automatically mean better climbing performance or greater sustained power.

For mountain climbing and racing, the important question is how effectively the complete motor system produces the required torque and power while managing heat.

Choose the motor based on the riding conditions, thermal requirements, wheel configuration, and compatibility with the complete ONYX electrical and mechanical system.

Most importantly, use a properly designed swingarm, verify axle retention and brake alignment, and configure the controller within the motor’s verified operating limits.