Decoding the "All-Terrain" E-Bike: How 90N·m Torque and Fat Tires Conquer Soft Sand

The “all-terrain” label is ubiquitous in the electric bike market, yet it often creates a promise that breaks down on the most challenging surfaces. Pavement, gravel paths, and hard-packed dirt are one thing; soft sand, deep snow, or loose mud are another entirely. These surfaces are the true test of an e-bike’s engineering, places where most standard bikes—and many under-equipped e-bikes—fail.

Why is soft sand such a challenge? It comes down to two physical problems: sinking and drag. Standard tires sink, and even if they could stay on top, the rolling resistance is immense. To truly conquer this environment, a machine needs a sophisticated, two-part solution. It needs to solve the “sinking” problem and the “power” problem. This isn’t about one magic component, but about an entire system working in synergy.

To understand this, let’s deconstruct the engineering principles using a powerful fat tire bike, the PUCKIPUPPY Samoyed, as a practical case study. This model’s specifications provide a perfect illustration of how “all-terrain” is achieved.

Part 1: Solving the “Sinking” Problem with Floatation

The first engineering challenge on sand is to stop the bike from digging itself into a hole. This is a problem of physics—specifically, ground pressure.

A standard tire, inflated to a high pressure, concentrates the rider’s entire weight onto a tiny contact patch. On sand, this pressure is too high, and the tire instantly sinks, bringing momentum to a halt.

This is where 26-inch fat tires come in. Their design is a direct solution to this problem. The “magic” isn’t just the width of the tire; it’s the ability to run at extremely low air pressures. By deflating the tire, the contact patch—the area of the tire touching the ground—expands dramatically. This larger footprint distributes the weight of the bike and rider over a much wider area, much like a snowshoe.

This principle is called “floatation.” The bike no longer cuts into the sand but “floats” on top of it. It’s this principle that allows some riders of well-equipped fat bikes to report, almost counter-intuitively, that they can “glide” over soft sand with ease. This isn’t marketing; it’s a direct outcome of successfully engineering for low ground pressure.

Part 2: Solving the “Power” Problem with Torque

Achieving floatation is only half the battle. Now that the bike is floating, it must contend with the second problem: immense rolling resistance. Pushing a wide, grippy tire across a soft, deforming surface requires a massive amount of energy.

This is where the motor’s specifications become critical, and it’s where most people look at the wrong number.

Many e-bikes advertise high peak wattage, like 960W Peak Power. This number is impressive, representing the motor’s maximum output for short bursts—think of it as horsepower, which relates to top speed. But horsepower won’t get you unstuck from sand.

The number that truly matters here is torque, measured in Newton-meters (N·m). If watts are horsepower, torque is raw, “truck-pulling” twisting force. It’s the rotational power that gets the wheel turning from a dead stop against all that resistance.

A typical commuter e-bike might offer 40-60 N·m of torque. To handle sand, you need significantly more. A bike like the Samoyed, for instance, is rated at 90 N·m of torque. This high-torque output is the “engine” that can overcome the “drag” of the fat tires. It’s this specification that directly translates to the bike’s claimed ability to conquer steep 35° slopes and, more importantly, to churn through the heavy resistance of a sandy beach without stalling.

The Support System: Battery, Frame, and Brakes

This high-torque, high-resistance riding style is extremely demanding on the entire system. This is where the other components must come together to support the mission.

First, this combination consumes energy at a rapid rate. A high-torque motor drawing peak power will drain a small battery in minutes. Therefore, a large “fuel tank” is essential. This is measured in Watt-hours (Wh), calculated by multiplying Volts and Amp-hours. A 48V, 15AH battery equates to 720Wh, a substantial capacity. While the manufacturer may claim up to 60 miles in ideal pedal-assist mode, real-world reports of 40-45 miles on a single charge are more realistic for mixed, high-demand use—a testament to the large battery’s necessity.

A removable battery design is also a practical consideration, allowing for convenient indoor charging and security.

Second, the frame and suspension must be able to handle the forces. An aluminum frame provides a necessary balance of stiffness and low weight (relative to steel), while front suspension becomes crucial not just for comfort, but for control, absorbing the jarring impacts of uneven, packed sand or transitioning back to pavement.

Finally, a heavy bike (often 70+ lbs) with a powerful motor requires high-performance disc brakes. They provide the essential, reliable stopping power needed, which is non-negotiable for safety.

Conclusion: The Engineering Synergy

An e-bike that can truly handle all-terrain, including soft sand, is not the result of one feature. It is a carefully balanced system. The “all-terrain” promise is fulfilled only when fat tires (for floatation) are paired with a high-torque motor (for power) and a high-capacity battery (for endurance).

When you see a spec sheet, you can now decode it through this lens. Look past the simple “watt” number. To find a true “go-anywhere” machine, look for the synergy: a high torque value (80-90 N·m or more), wide fat tires, and a large battery (700Wh or more). These are the engineering pillars that turn a marketing claim into a real-world capability.