There is no official 50cc Honda Grom—the Grom is a 125cc minibike. In stock form, it typically tops out around 60 mph (about 97 km/h), with actual speed varying by rider weight and conditions.
To understand the question and what speeds you can expect, this article reviews the Grom’s displacement, typical performance figures, and the factors that influence speed on this popular urban bike.
Engine and displacement basics
Displacement and power
The Honda Grom uses a 125cc four-stroke single-cylinder engine. It is designed for nimble urban riding and light highway use, delivering roughly 9–10 horsepower and modest peak torque. That combination helps keep the bike light and easy to handle rather than a high-speed highway machine.
Market naming and variants
In the United States and many markets, the bike is sold as the Honda Grom (also known as the MSX125 in some regions). Honda has not released an official 50cc Grom; any claim of a 50cc variant would involve aftermarket work or confusion with a different model.
Stock top speed: what riders typically see
Stock top speeds for the Grom generally sit around 58–65 mph (93–105 km/h). Real-world conditions—such as rider weight, wind, road grade, and model year differences—can cause modest deviations from that range.
Bottom line: the Grom is optimized for city streets and short highway stints, not sustained high-speed cruising.
Performance at a glance
Stock performance at-a-glance highlights the bike’s purpose and capabilities:
- Displacement: about 125cc
- Power: roughly 9–10 hp
- Top speed: typically around 58–65 mph (93–105 km/h)
- Wet weight: approximately 230 pounds (about 104 kg)
These figures reflect the common configuration most riders encounter in showrooms and on city streets.
What factors influence top speed on a Grom?
Several variables determine the actual top speed you’ll see on a Grom. Here are the most impactful:
- Rider weight and stance
- Altitude and air density (higher elevations reduce power slightly)
- Wind conditions and road grade
- Gearing (front/rear sprockets) and final drive ratio
- Engine condition, maintenance, and fuel quality
- Tire condition and proper tire pressure
- Intake/exhaust modifications and ECU tuning
- Electronic restrictions or rev-limiters in certain markets
In practice, most riders experience a relatively narrow band around the stock range, with adjustments in gearing or tuning able to nudge the limit up or down. Any modifications should consider reliability, fuel economy, and safety.
About the 50cc question and safety considerations
The Grom’s official displacement is 125cc, so there is no genuine 50cc Grom produced by Honda. If you encounter a claim of a 50cc Grom, it is likely a misunderstanding, a heavily modified engine, or a different model entirely. Modifying to a smaller or larger displacement can affect reliability, emissions compliance, insurance, and legality in many jurisdictions. Always ride within legal limits and adhere to local regulations.
Safety and practical speed considerations
Even when a bike is capable of higher speeds, urban riding emphasizes safe speeds, braking, and control. Always wear proper gear, ride within the law, and tailor speed to traffic conditions, weather, and your experience level.
Summary
The Honda Grom is a 125cc minibike, not a true 50cc model. In stock form, expect roughly 60 mph on level ground, with real-world speeds influenced by rider weight, altitude, weather, and maintenance. The notion of a genuine 50cc Grom is a misconception; any 50cc references are either aftermarket modifications or confusion with a different motorcycle or scooter. For those seeking a small, agile urban bike, the Grom offers a compact, fun-to-ride option, while keeping speed within typical city-friendly ranges.