Eclectic Electrics: Brammo Enertia vs. Zero S

MC Comparison

Electric vehicles are nothing new. The first battery-powered transports appeared in the 1890s, and for a while were favored over internal-combustion automobiles because they were quieter, cleaner and easier to operate. More than a century later, EVs are reemerging for the very same reasons, and this time motorcycles are included in the ranks.

Oregon-based Brammo and Zero of California are two prominent manufacturers that currently have street-legal electric motor-cycles on the market. Zero's supermoto-inspired S and Brammo's proletariat Enertia are aimed at commuters with performance to rival other economically efficient options. Where the engine and ancillary components would reside on your typical ICE (internal-combustion engine) bike, these e-bikes carry their oversized battery packs, while their efficient and compact motors reside like a scooter's down by the swingarm pivot. Power for the Brammo's brushless permanent-magnet Perm motor comes from an 85-pound lithium-ion battery comprised of 6 modules, with a total capacity of 3.1kWh. The S's brushed Agni PM motor draws off of Zero's patented 90-pound Z-Force L-I power pack, rated at 4kWh. Both have sophisticated battery-monitoring systems and integrated onboard chargers. The Enertia's 8-foot tether is coiled under the seat, while the Zero's 12-foot cord is stored in the hollow at the base of the subframe. Plugging into a standard 110-volt wall outlet will yield a full charge in a little over 4 hours.

The Zero uses an attractive hydro-formed aluminum twin-spar frame mated to a double-diamond swingarm, with an inverted fork sourced from mini-bike supplier Fast Ace and a shock from mountain-bike specialist Manitou. Duro street rubber rides on 16-inch wire-spoked wheels, controlled front and rear by Gator brake components. It's a robust-looking package, and one that Zero claims is "ready to aggressively take on urban environments," as any supermoto worth its salt should be.

Brammo bases its Enertia around a black-finished extruded-aluminum frame with a cast-aluminum subframe and tubular-steel swingarm. Its six-spoke aluminum hoops are shod with Avon rubber in 18-inch front and 17-inch rear sizes. Up front is a Marzocchi inverted fork while the back end is supported by an Elka shock. Braking bits are straight from Italy, with Brembo components all around. Designed as "an approachable, simple, lightweight motorcycle," the Enertia is uncomplicated in operation and appearance, a unique blend of old and new styling.

Aesthetically, the Zero has come quite a way since the debut model we sampled last year. Racy graphics, a less conspicuous headlight and restyled turn signals elevate the bike's appearance from toy-like to legitimate. For 2010 the S was updated with Z-Force air induction, which pulls hot air off the motor core for better efficiency and durability. Our testbike also came with the accessory low Corbin seat ($450), which is hard as a board with uncomfortably sharp edges. It does drop the seat height by 2 inches, however, giving shorter riders an alternative to the stock 34-inch saddle.

Throw a leg over either of these two e-bikes and you'll be welcomed by an upright riding position and ample leg room. While they're both slim between your knees, the Zero has a more compact cockpit better suited to sub-6-foot riders, whereas the Enertia's higher bars and lower footpegs are a better match for taller pilots. The Enertia's seat rests 32 inches off the ground, and although it's narrow, it's softer and much kinder on your backside than the optional perch on our Zero.

The Zero's stronger Agni motor and larger-capacity battery give it a leg up on the Brammo in terms of acceleration and top speed, and it's simpler to start, too. Turn the key and, 5 seconds later, the green light on the dash illuminates, indicating "all systems are go" and the throttle is live. Twist it and the bike whooshes forward like a magic carpet, although not as quickly as the last S model we sampled. Zero says the electronic controller was reprogrammed to improve range, which presumably entailed curtailing power output.

The Enertia's boot-up procedure takes five times longer due to a multi-step start sequence. Brammo incorporated these safety features to prevent unintended acceleration, which is an issue since these bikes emit no noise while running. Pulling away from a standstill on the Enertia is far from thrilling, but it'll still best the average sedan in a stoplight drag race, which makes all the different in urban riding.

The Zero indicates battery status using a repurposed fuel gauge, with 11 bars representing a full charge. It's a crude instrument compared to the Brammo's comprehensive digital display, which conveys estimated range, remaining battery charge, current power draw and other useful data. Range anxiety is an ever-present issue, and the Brammo's informative interface helps placate the rider's fear of getting stranded. It's the same situation when it comes time to charge up. The Brammo ticks off the time remaining until a full charge is achieved, whereas the Zero uses LEDs on the battery pack to convey charging status.********

With no reciprocating parts there is no vibration, so the rearview mirrors remain clear at all times and numb appendages are a thing of the past. Power is delivered with a fluidity and progressiveness unmatched by any conventional motorcycle, and direct drive eliminates the need for shifting, so accelerating is as simple as twisting the throttle. Both bikes are respectably light-the S weighs in at 282 pounds, while the Enertia is 50 lbs. heavier-and handle accordingly. Although the Zero's suspension is more sophisticated, the Enertia yields a plusher ride, and its throttle response is more refined, too. Maximum velocity for the Zero is about 75 mph, while the Brammo tops out at 65 mph with my 175 lbs. onboard. If a comparison must be made, these e-bikes' performance is about on par with small-bore motorcycles like the Honda Rebel or CRF230, but not quite as quick as a Ninja 250. Once underway, they're eerily quiet. The only noise is the whine of the motor and the whizzing of the chain.

Besides the silence, the lack of engine braking is the most foreign part of the e-bike riding experience. With no engine compression to slow you down when you roll off the "gas," you are entirely reliant upon the brakes to shed speed. That brings to light the Zero's biggest flaw: its feeble front brake. Pull in the lever and it comes back to the grip without generating much useful friction. The problem was bad enough that we requested a replacement bike, but that machine demonstrated the same inadequacy. Zero reps say they're aware of the problem-which stems from an undersized master cylinder-and are in the process of remedying it. The Brammo's Brembos are superb, with good feel and more than enough power to pull a stoppie.

The only issue we encountered with the granny-apple green Enertia was an inability to effectively manage the motor heat that is an inevitable byproduct of the electricity-to-motion conversion. Tucked between the swing-arm pivots is its 30-pound motor, and once that sucker heats up, it doesn't want to cool down. The cooling fan runs incessantly during anything but the gentlest ride, and a "Thermal Cutback" warning frequently appears on the dash during more spirited adventures. Meanwhile, the Zero's temperature warning never illuminated, no matter how hard we flogged the bike. Its open-core motor and Z-Force cooling system are simply a better design.

Off the Record
Ari Henning
Age: 25
Height: 5'10"
Weight: 175 lbs.
Inseam: 33 in.
If you feel largely unseen on your gas-powered motorcycle, riding a whisper-quiet electric bike is like donning an invisibility cloak. During the three weeks I rode the Brammo and the Zero, the instances of drivers pulling out in front of me or moving into my lane doubled, plus I had more than a few pedestrians step into the street in front of me. Riding these silent transports makes you keenly aware of just how much people rely (whether consciously or not) on the sound of a bike's exhaust as a cue to look over their shoulder. I hate to add fuel to the "loud pipes save lives" fire, but there is something to be said for the safety benefits of making some noise.

You'll have to exploit the bikes' coasting capabilities if you want to attain both manufacturers' claims of an average 40-mile range. In an attempt to test that, we followed a suburban course selected for its minimal stop signs and elevation changes. Trolling along at the speed limit, rolling the throttle open as gently as conditions allowed, the S covered 38 miles. As battery power dwindles the Zero's speed comes down, and after the last bar of energy disappears from the energy gauge the bike begins emitting an audible warning. When you hear that, it's time to plug in or start pushing.

Over the same course, the Enertia made it 34 miles. At 20 percent capacity the low-battery warning comes on. At 10 percent things get dire. Asking the battery for too much, say by rolling the throttle open too quickly, results in a total system shutdown: no motor power, turn signals or brake light. Granted, arriving at that rather dangerous scenario requires you to ignore the steadily declining numbers on the dash, but it would be nice if there was a last-chance warning similar to that of the Zero.

Alternatively, holding it pinned on the freeway will net you about 23 miles on the S, and slightly less on the Brammo. The superslab, you say? While we were initially wary of pointing either bike down a freeway entrance ramp, they are capable. Sure, you'll feel safest hiding in the shadow of a slow-moving school bus, and you may have to utilize a faster vehicle's slipstream to make a pass, but it's nothing riders of small bikes and scooters aren't accustomed to. Keeping the pace down improves range dramatically, but the distance traveled on an electron load ultimately depends on your trip profile, which includes factors such as your weight, rate of acceleration, speed, number of starts/stops and changes in elevation. As they say in infomercials, "Your results may vary."

Compared to their small-bore ICE counterparts, these e-bikes are pretty pricey. Brammo's Enertia costs $7995, and that's after improvements in manufacturing and a $10 million deal with Best Buy knocked $4000 off its price tag in 2009. The Zero S rings in at a hefty $9995. Look to the operating expenses, however, and things start to balance out. A full charge rings in at well under a dollar and there are no expensive maintenance procedures to be performed. The motors are expected to last the life of the machine, and the battery is said to have a 5-year lifespan for the Zero and an 8-year lifespan for the Brammo under everyday use. Then there's the 10 percent federal EV tax credit and the unquantifiable satisfaction you'll get from knowing you're emitting zero tailpipe emissions. Admittedly, with the current grid makeup the batteries are most likely pulling their charge from a coal-fired powerplant, but if you do the math the operational cost equivalent comes out to 300-400 miles per gallon. You can't beat that with a Louisville Slugger!

For the worker with a short commute, there's no sacrifice required to ride one of these e-bikes, and it's undeniably liberating to disregard gas stations and their ever-increasing prices. While the Brammo is a little dull, it doesn't do anything wrong. It was designed as a commuting appliance, and it serves that purpose obediently. The Zero is quicker and cooler, but its flaws cannot be ignored. Inferior brakes and a torturous seat weren't our only grievances. Less than 100 miles into our test a number of spokes on the rear wheel worked dangerously loose, requiring the wheel to be trued and re-tensioned. Although the Brammo has heat-management issues, that doesn't inhibit its performance or functionality. Commuters will appreciate the Enertia's reliability, comfort and communicative data display. The fact that it costs $2000 less than the S, comes in a spectrum of colors, and can be purchased at your local Best Buy store makes it a clear winner for the hard-working and discerning commuter.

Off the Record
Marty Estes
Age: 40 **
**Height: 6'2"

Weight: 220 lbs.
Inseam: 34 in.
Having never ridden anything powered solely by electricity, it was a real trip to take these e-bikes for a spin. The silence is truly unnerving at first. You hear sounds that exhaust noise normally masks.

While the Zero's cooling system is better than the Brammo's, my added weight and heavy throttle hand overloaded the system, and I found myself coasting with the warning light blinking. It recovered quickly, but it did overheat.

Ergo-wise, both bikes run small for a bigger guy like me. Being a dirtbike rider, the Zero felt familiar and comfortable, whereas the Brammo's footpegs were too far forward. These e-bikes aren't for everyone, and with my 50-mile commute they're clearly not yet an option.

Brammo Enertia | Price $7995

Since there's no spark plug lead to tap into during dyno runs, determining motor rpm took some arithmetic. As with all electric motors, torque is abundant from anything above 0 rpm, with the Brammo putting down 41 lb.-ft. at 925 rpm and a modest 15.3 bhp at about 3100 rpm.

Tech Spec

Motor type: AC brushless PM electric
Battery: Valence lithium-ion
Battery capacity: 3.1kWh, 55.5v peak
Clutch: Direct drive
Transmission: na
Frame: Aluminum twin-spar
Front suspension: 46mm Marzocchi fork with adjustable compression damping
Rear suspension: Elka shock with adjustable compression damping
Front brake: Brembo two-piston caliper, 290mm disc
Rear brake: Brembo single-piston caliper, 220mm disc
Front tire: 100/90-18 Avon Roadrider
Rear tire: 130/80-17 Avon Roadrider
Rake/trail: 24.0°/3.5 in.
Seat height: 32.0 in.
Wheelbase: 56.0 in.
Measured weight: **332 lbs.
**Measured horsepower:
15.3 bhp @ 3125 rpm
Measured torque: 41.0 lb.-ft. @ 925 rpm
Corrected 1/4-mile: 20.8 sec. @ 60.1 mph
0-60 mph: 19.6 sec. Top-gear roll-on 60-80 mph: na
Range (high/low/avg.): 34/20/26 mi.
Colors: Green, blue, orange, white, silver
Availability: **Now
12 mo. bike/24 mo. battery, unlimited mi.
Contact: Brammo Motorsports LLC
550 Clover Lane
Ashland, OR 97520

A lower seat, higher bars and platform footrests that are a full 5 inches lower and several inches farther forward than the Zero's make the Enertia feel rather cruiserish. It's relaxed and roomy, which is excellent for tall riders, but still comfortable for shorter people.

Zero S | Price $9995
More horsepower means more speed, and the Zero's extra 5 bhp translate to 10 mph on top. Its 50 lb.-ft. of torque is nothing to scoff at, and is what helps hustle the S off the line quicker than its competition.

Tech Spec

Motor type: AC brushed PM electric
Battery: Z-Force lithium-ion
Battery capacity: 4kWh, 58v peak
Clutch: Direct drive
Transmission: na
Frame: **Aluminum twin-spar
**Front suspension:
48mm Fast Ace inverted fork with adjustable compression and rebound damping
Rear suspension: Manitou shock with adjustable spring preload, compression and rebound damping
Front brake: Gator two-piston caliper, 260mm disc
Rear brake: Gator single-piston caliper, 228mm disc
Front tire: **110/70-16 Duro DM1060
**Rear tire:
140/70-16 Duro DM1057
Rake/trail: **22.0°/3.3 in.
**Seat height:
32.0 in. (low seat)
Wheelbase: 56.8 in.
Measured weight: 282 lbs.
Measured horsepower: **20.5 bhp @ 2150 rpm
**Measured torque:
52.9 lb.-ft. @ 575 rpm
Corrected 1/4-mile: 19.2 sec. @ 63.9 mph
0-60 mph: 11.9 sec.
Top-gear roll-on 60-80 mph: na
Range (high/low/avg.): **38/19/26 mi.
**Colors: **White, red, blue
Availability: Now
Warranty: 24 mo., unlimited mi.
Zero Motorcycles
1 Victor Square
Scotts Valley, CA 95066

With a standard 34-inch seat height, wide bars and high footpegs, the Zero S feels exactly like your standard 250cc supermoto bike. Our only complaint was the agonizingly hard accessory low seat. If you're tall enough, stick with the softer stock saddle.

Three selectable screens show the status of every operating system on the Enertia. Battery charge, motor temperature and even the condition of each cell stack are available at the touch of a button.
Like the Zero's 16-inch wheels, the Enertia's 18-inch front hoop limits tire choices. The stock Avon Roadriders are excellent, so there's no need to seek out an alternative.
Originally designed for dirty industrial applications, the Enertia's Perm motor is a sealed unit. It's also encased in body panels, which makes that little cooling fan's job especially difficult.
You'd be hard pressed to find a bike with a simpler, cleaner appearance. Plastic bodywork completely conceals the battery and all electronics. Accessory saddlebags boost the Brammo's utility.
Designed by Zero founder Neil Saiki, the Zero's 18-lb. aluminum frame is a work of art, with clean welds, machined details and an attractive brushed finish.
Zero juxtaposed quality components like the exquisite frame with budget bits like this universal motorcycle dash. The repurposed fuel gauge/volt-meter is imprecise, making it difficult to rely on.
A fan in the Zero's tail section pulls hot air off the vented Agni motor to maintain consistent operating temperatures. The Manitou shock is fully adjustable and easily accessible.
The S's Taiwanese Gator brakes aren't up to par. That coiled plastic sheath contains the wiring for the wheel-speed sensor, which pulses blue when the bike is in motion.