The electric mountain bike (eMTB) market has traditionally been defined by strict speed cutoffs and subtle pedal-assist motors. But every now and then, a machine hits the dirt that shatters the rules of what an eMTB is allowed to be. The Bonnell 775 MX is currently one of the most talked-about, controversial hybrids in the industry. Blurring the lines between a downhill mountain bike and a lightweight electric dirt bike, its raw speed and power have left riders with one burning question: How fast does the Bonnell 775 MX actually go?
Let’s dive into the factory performance specs, look at real-world data, and explore how a simple mechanical adjustment can unlock even more speed from this high-voltage powerhouse.
The Powertrain Specs: Motorcycle Power on an MTB Frame
The secret behind the blistering velocity of the Bonnell 775 MX isn’t just a clever software tweak; it’s a massive mid-drive powertrain integrated directly into a lightweight, 75-pound chromoly frame.
The Core Motor: Equipped with a high-end CYC X1 Pro Gen 4 mid-drive motor.
Peak Power Output: Pumps out an incredible 6,000 watts of peak power. For context, that is up to five times more powerful than a standard premium eMTB.
Raw Torque: Generates a massive 280 Nm of torque at the crank, giving it enough punch to wheelie effortlessly on command.
The Battery Pack: Driven by a high-voltage 65V 1,300Wh lithium pack built with premium Samsung 50S cells.
Because the factory firmware does not feature an artificial speed limiter, the top end of this bike is purely governed by physics, battery voltage, and mechanical gearing.
Real-World Performance: Tracking the Top Speed
1. Stock Factory Top Speed (~37 MPH)
Straight out of the crate with the standard factory configuration, the Bonnell 775 MX consistently clocks a top speed of 37 to 38 MPH (60 km/h) on throttle alone. Because the bike is incredibly lightweight compared to a full-sized eMoto, it hits this top speed almost instantly when you twist the Lekkie Pacemaker throttle.
2. The Gearing Effect: Sprocket Upgrades
While the factory settings aren’t electronically capped, you will hit a mechanical ceiling around 40 MPH due to the stock 24T (24-tooth) drive sprocket. Because it uses a fixed-gear design, changing your physical sprocket sizes directly transforms how the bike handles top-end speed versus bottom-end climbing power:
The 22T Sprocket Upgrade (~40+ MPH): Dropping down to a smaller 22-tooth sprocket allows the motor to spin faster relative to the rear wheel. This mechanical adjustment pushes the real-world top speed to 40 MPH (65 km/h), making it ideal for flat trails and fast fire roads.
The 26T and 28T Sprockets (31–34 MPH): If you swap to a larger sprocket, you sacrifice some top-end speed. However, it unlocks extreme hill-climbing torque, allowing the bike to effortlessly “rooster” up vertical, sandy inclines.
3. Pedaling at Top Speed
The Bonnell 775 MX includes traditional mountain bike pedals and a pedal-assist mode. However, because the low-speed factory gearing is optimized to handle the immense torque of the 6,000W motor, human pedal assist essentially cuts out around 12 MPH. Past that point, your legs simply cannot spin fast enough to keep up with the motor. This bike is built to be ridden primarily via the throttle.
The Verdict: Fast, Furious, and Trail-Ready
The Bonnell 775 MX isn’t designed for casual bike paths or highway cruising. It is built to simulate a high-speed, downhill mountain bike racing experience on any terrain you throw at it.
If you want balanced performance: Keep the stock 24T setup to cruise smoothly at 37 MPH with excellent out-of-the-hole acceleration.
If you want maximum speed: Swap to the 22T sprocket to breach the 40 MPH barrier on flat straights.
Experience the Power at Ronster Bikes
Ready to experience a completely new breed of electric performance? At Ronster Bikes, we bypass the long factory backlogs and high dealer markup fees to get you on the dirt faster.
The high-voltage Bonnell 775 MX is available to order through our fully secure checkout system. Every bike ships directly via tracked global freight in heavy-duty protective crates and features an official manufacturer factory warranty.
Browse our inventory today, pick your sprocket size, and prepare to redefine your trail rides.