AIMA Big Sur 2.0 Review | Big, Burly, and Buckets of Fun

With its 750W rear-hub motor and gigantic 48V, 960 watt-hour (Wh) battery, AIMA estimates that riders should expect 40 to 75 miles of range from a single charge. Our two Range tests, consisting of both max-assist and low-power trials (as explained in the graphic above), verified this advertised claim with results of 38.6 and 79.0 miles.

Both of these results line up well with the Range Test results of similar fat tire e-bikes we’ve tested; a group of comparable popular models tested recently averaged 36.5 and 75.2 miles, respectively. With the exception of one mid-drive-equipped e-bike, these models boasted similar 750W motors and batteries averaging 847 Wh of capacity.

So why did the Big Sur 2.0 not exceed the averages by a larger margin with an additional 113 Wh of battery capacity? In short, because the bike used slightly more energy per mile on average than its competitors, as explained below:

By dividing battery capacity by the number of miles traveled, we can determine that the Big Sur 2.0 used roughly 12.2 watt-hours per mile (Wh/mi) in its PAS 1 test and around 24.9 Wh/mi in PAS 5. Our group of comparison models averaged 11.7 and 23.6 Wh/mi; the differences between these figures are relatively small, but they do add up over many miles.

Still, average performance (or slightly above-average, in the Big Sur’s case) is excellent, as it shows that the bike in question is appropriately specced to match its peers. Those who use the bike’s cadence-sensing mode should expect fewer miles, however, as this setting’s steady motor output reduces its energy efficiency.

We’re highly satisfied with the Big Sur 2.0’s results; they show that riders should be able to enjoy multiple rides before needing a recharge, no matter what power level they select. We’re also confident in saying that riders should have plenty of charge for commuting, leisure riding, and urban or light off-road exploration.

The bike is shipped with a 3A charger that can power up a depleted battery in under 7 hours, allowing for convenient overnight charging.

Fat tire e-bikes are loved for their ability to flatten hills; their powerful motors allow riders of all ages and experience levels to tackle otherwise intimidating climbs with confidence. To ensure that the AIMA Big Sur 2.0 was up to the task, we used the process explained above to test its throttle and pedal-assisted power in the same way we have tested its peers.

Using 100% throttle power alone, our test rider, Justin, reached the top of our test hill in 1:48 at 16.8 mph on average. When pedaling in PAS 5, that time was reduced to 1:44, with a faster average speed of 17.4 mph.

Similar fat tire e-bikes we’ve tested averaged 1:56 and 1:54, respectively, making the Big Sur noticeably faster than average, though the reasoning behind that is not extremely clear.

Weight, torque, and peak motor power are all factors that influence a bike’s results in this test. With a weight of 83 lbs, a maximum torque output of 85 Newton meters (Nm), and a motor that peaks at 1200W, the Big Sur is relatively average in all three areas.

The group of similar models used for comparison averaged a slightly lighter 82 lbs, a slightly higher 90 Nm of torque, and a slightly lower peak of 1150W. We’d expect these small differences to (more or less) cancel each other out, but the Big Sur 2.0 managed results that were 8-10 seconds faster than its peers.

My personal experience on the bike justifies its speedier climbing times, especially when pedaling uphill. I found it remarkably easy to reach the top of our challenging secondary test location, called Pilot Hill, with only relaxed pedaling and a light amount of effort. The Big Sur also had no trouble when throttling, proving itself relatively unphased by the test.

In conclusion, riders should expect a fun, easy, and low-to-no-effort experience when dealing with average or large hills. Our test proves that this e-bike would be a great match for those who live in areas with varied terrain.

As you might expect, our Brake Test evaluates an e-bike’s ability to stop safely and predictably. Using the method above, we determined the Big Sur 2.0’s average stopping distance to be 22’8”. This distance places it firmly within the bracket we consider to be safe and trustworthy.

Similar models, including many of the best fat tire e-bikes we’ve tested, averaged 21’8” in our testing, placing the Big Sur 2.0 exactly one foot beyond average. Once again, the reason for its difference is not immediately apparent, but I do have an educated guess.

Many factors influence this test, including a bike’s weight, brake system, tire tread, etc. As mentioned above, the Big Sur 2.0’s weight of 83 lbs is relatively average. Its brake system, the hydraulic Tektro HD-E3520, is a common two-piston system we’ve tested numerous times; it has proven consistent and reliable. Finally, the Big Sur’s 26×4” knobby tires are a standard for the category, so nothing stands out as unusual unless we dive deeper.

On the positive side, AIMA smartly equipped the Big Sur 2.0 with larger-than-average 203mm brake rotors, which are more effective at dissipating heat and increasing overall stopping power than more common 180mm rotors.

A factor that could potentially decrease the bike’s stopping power is geometry; its uncommonly upright riding position encourages comfort, but distributes the rider’s weight differently than many of the somewhat sportier models we’ve tested with a more forward-leaning posture.

Case in point: a group of upright cruiser-style e-bikes we tested averaged 22’9” in their brake tests—just beyond the Big Sur 2.0’s result.

Despite its somewhat longer than average score, the Big Sur 2.0’s brakes felt capable and strong overall. At times, modulating speed when riding downhill required me to apply a fair amount of pressure to the brake levers, and I experienced a not-unusual amount of skidding after hard braking, but the system had the bite and force to bring me safely and quickly to a stop throughout my testing.

A bike’s ride quality is a comprehensive summary of how it feels to ride and operate. This broad category of analysis involves the bike’s geometry, fit, features, motor engagement, suspension, and many other factors. The Big Sur 2.0’s overall ride quality is great, though there are a few points prospective buyers should be aware of.

In terms of sizing, the bike has a single step-thru frame that fits riders from 5’2” to 6’2”. While this bracket should encompass the vast majority of riders, it potentially leaves out some folks on the extreme ends of the height spectrum; we wouldn’t mind seeing an additional size or a high-step model (with more than a single color option) offered with future iterations of the Big Sur.

At 5’11”, I found the bike generally comfortable, though the relatively steep angle of its down tube resulted in the cockpit feeling a little tight. The bike’s six inches of saddle height adjustment wasn’t quite enough to provide full leg extension, but the powerful motor and the sensitivity of the torque sensor largely made up for this. I greatly appreciated the adjustable stem, which allowed me to set a comfortable and ergonomic handlebar height.

The Big Sur 2.0’s saddle is thick, supportive, and soft, making it appropriate for comfortable and relaxing cruises. Its ergonomic rubber grips are also similarly cushy and easy to enjoy. The bike’s ride is softened further by its 80mm Zoom suspension fork and 4” fat tires, which can be adjusted for comfort and traction.

Many of its features are reminiscent of a cruiser, and much of its design reinforces this intent. In addition to its relatively upright, comfortable riding position, the bike’s fenders seem to be integral; their removal (which we typically recommend for off-roading) could allow mud to reach the down-tube-integrated battery.

Additionally, the bike is loaded with urban-friendly features, such as brake lights, turn signals, and an MIK-HD cargo rack. We always appreciate these features for their safety and utility factors—the cargo rack can be equipped with standardized third-party accessories that lock into place, including cargo bags or a child seat.

Handling is generally predictable, though I noticed the bike’s weight, particularly when cornering. Despite feeling as though it naturally wanted to oversteer, however, its steering stayed true. Like all fat tire e-bikes, the Big Sur 2.0 felt stable while riding, with a wide contact platform with the ground and knobby tread for grip on dirt or gravel.

As mentioned above, the pedal assist system felt extremely responsive and the motor’s ample power made for easy pedaling. I also found it notably quieter than many other rear-hubs I’ve tested, with only a gentle whirr instead of a potentially distracting whine.

Of course, there is the bike’s user interface and programming customization options to cover. Its electronic components are operated by two modules: a simple button pad on the left handlebar that turns it on/off and adjusts power levels. The right handlebar hosts a module for its lights, turn signals, and horn, which offers a tactile, user-friendly feel.

Riders can change the color display’s theme and switch between sensor modes via the settings menu or adjust motor output through the display or app. The display offers control over the set speed and power limits for each assist level, while the Bafang Go app adds another metric for sensitivity. Bafang’s app can also be used for ride data tracking (manual or automatic), navigation, and phone message synchronization with the display.

Overall, the bike’s feature package, user interface, and app options are robust without being overcomplicated. The Big Sur 2.0 is cushy, well-equipped, and both enjoyable and easy to use.

The Big Sur 2.0 is the successor to one of our audience’s most requested e-bikes. Despite hearing time and time again how satisfied buyers were with their purchase, we couldn’t comment on the bike until after we put it through our full evaluation process—and I’m glad to be able to say that every commenter who raved about it was spot-on.

Highly customizable e-bikes are not new, but in my experience, they can be tough to balance. Bikes that offer too many options can present a significant learning curve to new riders, while those with too few options feel lacking.

The Big Sur 2.0 strikes a great balance between these extremes, with a great feel right out of the box, and lots of meaningful choices for those who wish to explore them.

The bike performed well across the board, with test results that proved it to be a rockstar in the range department, a capable hill climber, and safe when stopping matters most. Its default pedal assist system programming was solid, and clearly tuned for its standard torque-sensing mode. It also offers an impressive number of choices for riders who want to personalize its feel and performance.

We identified only a few minor areas worthy of critique, which have been relatively consistent across most AIMA e-bikes we’ve tested. We feel that it would be more convenient for bike owners to be able to adjust their own speed settings instead of bringing their bike to a dealer. Additionally, while the Big Sur’s single frame size and color will likely appeal to most folks, more options would be welcome.

Otherwise, the Big Sur 2.0 is well-suited for riders across a wide range of heights, weights, ages, and experience levels. Its design, features, and customization options make it a great option for riders seeking a daily commuter, a sturdy leisure bike, an errand-runner, a light adventure bike—or a combination of each of these roles.

Happy Riding! Make sure to let us know if you have any questions or if you think we left anything out in this review of the AIMA Big Sur 2.0 down in our comments section.