This page is part of the ONYX Performance Guide
This post covers practical ONYX motor cooling, with a focus on real-world heat behavior, regenerative braking, and cooling upgrades such as Statorade and Hubsinks. The goal is to explain where motor heat actually comes from, how much regen contributes, and what cooling changes are worth considering for harder riding.
For most owners, the main point is simple: normal riding does not push the motor anywhere near its thermal limits. Cooling upgrades matter more when the bike is ridden aggressively, held at speed for long periods, or repeatedly loaded hard.
- Regenerative braking adds very little heat in real-world riding
- Sustained high load creates more motor heat than normal commuting
- Statorade helps move heat from the stator to the hub shell
- Cooling upgrades matter most for riders chasing sustained performance
How ONYX Motor Heat Works
Motor heat on an ONYX mostly comes from load over time.
That means repeated hard acceleration, sustained high speed, steep grades, and aggressive riding patterns do more to raise motor temperature than normal stop-and-go commuting. In everyday riding, the motor usually stays in a comfortable thermal range.
The important thing to understand is that peak power is not the whole story. Duration matters. A short burst of power is very different from holding the motor under heavy load for long periods.
| Riding Condition | Heat Effect |
|---|---|
| Normal commuting | Low to moderate heat |
| Repeated hard acceleration | Higher heat buildup |
| Sustained high speed | Significant heat buildup |
| Long climbs or heavy load | Significant heat buildup |
Regen Braking Motor Heat
Regenerative braking adds very little heat to the motor in real-world riding.
In testing across a wide range of riding conditions, including cruising around 25 mph, high-speed runs around 70 mph, and steady downhill riding around 35 mph, motor temperature increased by only about 4°C (7.2°F).
That is an extremely small thermal change and nowhere near the kind of temperature increase that would normally stress the motor.
- 25 mph cruising: negligible temperature change
- 70 mph high-speed riding: still minimal regen heat contribution
- 35 mph downhill steady regen: small gradual increase only
- 4°C (7.2°F) total observed increase: very low thermal load overall
Why Heat Becomes A Limitation
As motor temperature rises, the bike has less thermal headroom.
That matters because excessive heat can reduce sustained performance, increase the chance of thermal throttling, and put more long-term stress on motor components. Riders who spend most of their time commuting normally may never run into this. Riders doing long aggressive pulls or sustained fast riding are more likely to care.
| Heat Outcome | Practical Result |
|---|---|
| Low motor temperature | Full thermal headroom |
| Rising motor temperature | Reduced sustained margin |
| High internal temperature | More thermal stress |
| Excessive heat over time | Greater chance of performance reduction |
What Statorade Is
Statorade is a ferrofluid developed by Grin Technologies that improves cooling inside electric hub motors.
Magnetic particles suspended in the fluid keep it positioned in the air gap between the stator and magnets. That allows heat from the stator windings to transfer more efficiently to the motor shell.
Normally that air gap acts as a thermal barrier. Statorade helps bridge that gap.
How Statorade Works
The job of Statorade is to move heat from the part of the motor that gets hot internally to the shell where airflow can remove it.
Without a thermal bridge, the stator has a harder time shedding heat into the outer hub shell. With Statorade in place, heat transfer improves and the shell can do more of the cooling work.
| Upgrade | Function | Result |
|---|---|---|
| Statorade | Transfers stator heat to shell | Lower internal motor temps |
| Hubsinks | Increase shell heat dissipation | Better sustained cooling |
| Combined | Stator → Shell → Air | Maximum cooling effect |
This is why Statorade and Hubsinks are often discussed together.
Real-World Results
Testing during a 50 mile aggressive ride showed a meaningful temperature reduction when Statorade was used.
| Metric | Result |
|---|---|
| Temperature drop | ~30°C (54°F) |
| Motor temps with Statorade | ~90–110°C |
That kind of reduction can improve sustained power and reduce the chance of thermal throttling during hard riding.
For riders who rarely push the bike thermally, the benefit may be less noticeable. For riders who do, it can be significant.
Statorade Benefits And Trade-Offs
Statorade offers clear cooling benefits, but it is not a free upgrade.
Benefits:
- improved cooling during hard riding
- reduced motor temperatures
- better sustained acceleration
- increased thermal headroom
- improved motor longevity
Trade-offs:
- ~20–30 RPM reduction
- ~0.25 mph top-speed loss
The trade-off is small, but it exists. For most riders focused on sustained performance, the cooling gain is worth it.
RPM Cooling Behavior
Statorade works best within a practical speed range. As speed rises, centrifugal force pushes the ferrofluid outward, reducing the amount of fluid bridging the thermal gap in the way it does at lower RPM.
That means cooling effectiveness changes with wheel speed.
| MPH | RPM | G-Force | Cooling |
|---|---|---|---|
| 20 | 290 | 10 | Strong |
| 30 | 440 | 20 | Optimal |
| 40 | 585 | 35–40 | Declining |
| 50 | 730 | 60 | Reduced |
| 60 | 880 | 85–90 | Minimal |
This is why briefly slowing to around 30–35 mph for several minutes can help the motor shed heat more effectively after a hard run.
When Cooling Upgrades Make Sense
Cooling upgrades are most useful for riders who regularly push the motor beyond normal commuting loads.
That usually means:
- aggressive riding
- repeated hard acceleration
- long fast runs
- heavy thermal use over longer distances
- sustained riding where thermal throttling becomes noticeable
For casual city riding, cooling upgrades are less urgent. For harder use, they become much more relevant.
| Rider Type | Cooling Priority |
|---|---|
| Casual commuter | Low |
| Mixed street rider | Moderate |
| Aggressive rider | High |
| Sustained high-load rider | Very high |
Statorade Installation
The recommended amount is:
- 10 ml per motor
There are two common installation methods:
- Drill-and-inject
- Direct injection
Both methods work. The right choice depends on how much disassembly you are comfortable doing.
Drill Method
The drill-and-inject method is the simpler path for many owners.
- 80V ONYX: right chain side of the hub
- 72V ONYX: left chain side of the hub
| Parameter | Recommendation |
|---|---|
| Drill bit | ≤ 1/8 inch |
| Speed | Medium |
| Pressure | Light |
| Hole count | 1 |
A syringe can fit into holes as small as 2 mm.
Tip: coat the drill bit with grease to help capture aluminum shavings.
After injection, seal the hole with black Gorilla tape.
Direct Injection
Direct injection involves removing the phase-side motor cover and injecting the fluid directly between the magnets.
This is the most precise method, but it requires partial disassembly.
Common Cooling Misunderstandings
A few cooling assumptions come up often.
- regen is usually not the main heat problem
- short bursts of power do not tell the whole thermal story
- cooling upgrades help sustained use more than casual use
- lower internal motor temperature can matter even if top speed changes slightly
The key point is that cooling should be matched to actual riding style, not just added automatically.
Bottom Line
ONYX motor cooling matters most when the bike is ridden hard enough to build sustained heat.
Regenerative braking contributes very little heat in normal real-world use. The bigger thermal issue is repeated heavy load over time. For riders who push the bike aggressively, Statorade can meaningfully reduce internal motor temperatures and improve sustained performance, especially when combined with Hubsinks.
For normal commuting, the stock setup is usually enough. For harder riding, cooling upgrades start to make real sense.