The stealth rider

Before I tried out the Zero DS, an electric Dual Sport motorcycle by Zero Motorcycles of Scott’s Valley, Calif., I theorized that an electric motorcycle would be impractical for a law enforcement application. But wouldn’t you know, the Zero DS proved itself worthy, and even exposed some patrol applications that hadn’t occurred to me until the test.

I rode Zero DS for over a week any time I had even a moment to run it. I used it for every conceivable situation, as often as possible, and I tried every charging scenario I could imagine. I ran it in shallow water, triple digit weather and over fairly uneven terrain. Throughout, the motorcycle ran as advertised and delivered impressive performance. I tried it with soft panniers, to simulate having clipboards and forms on board. But I got tired of dragging them through dirt and branches, so I took them off.

The Zero DS is a mid-sized bike at 297 pounds. If I were to compare its handling to a conventional motorcycle, I would say it feels like a 350cc to 400cc supermoto. It was competent in winding roadways with its 56.3 inches of wheelbase, coupled with a unique frame and swing arm.

The controls and console are pretty standard, except for the lack of a clutch, tachometer and the presence of a throttle switch. This is a rocker switch that sits where the right thumb rests. The large part of the switch disconnects the throttle for safety.

With the standard seat, it sits a little high at 35.8 inches. The optional seat brings it down almost 3 inches. I’m average height, and 35 inches was just right for me. This was the first advantage of having a dual sport law enforcement tool: The officer can see over the average sedan when seated.

Zero claims the bike has to have about a 4-hour recharge time. The charge indicator consists of a series of indicator LEDs. One plugs it into a standard 110-Volt outlet using a pigtail that looks exactly like the three-pronged male end of an old computer tower-to-monitor plug. The bike comes with the cord that connects to the pigtail, which I stuck into my cargo pocket when I rode out of town. A quick-charge module cuts charge time to 2.3 hours. I didn’t use one, nor did I need one. It never took 4 hours to charge, even when I nearly depleted the power pack. Charge time was usually closer to 3.5 hours, as long as the indicator in the cockpit has one or two bars left.

I also toyed with the charge a bit. I figured some officers would pull into the station in the middle of a shift with a half charge and plug it in to top it off. I topped it off for an hour from a little more than half a charge a few times and often interrupted the charge, stopping at a 3/4 level several times. This did not affect performance or capacity.

The Zero DS charge indicator consists of ascending horizontal bars on the right side of the console. It even has a gas pump icon (which appeals to my dry sense of humor). The indicator accurately indicates the charge, then rapidly disappears when one cranks hard on the throttle only to reappear when one lets off. This, apparently, is encouragement to conserve the battery pack, which I didn’t. Really, the DS costs about $.48 to recharge, which means that several bikes plugged in simultaneously won’t spin my electric meter any faster. It was plain cheap to run.

Zero advertises a maximum range of 58 miles. This varies depending on riding style. I found that I did get more than twice the mileage riding at approximately 30 mph as opposed to 60 mph. But twice the mileage is not worth half the fun, and I was satisfied with 25 to 30 miles or so on a brisk ride. I got a little bored on the back roads and kept passing cars. I got over 50 miles per hour during several rides. In its law enforcement application, this is really perfect. The bike can literally do 4 to 5 miles an hour, a walking pace. And still officers can be at 60 mph in a matter of seconds. Like a gas product, I reduced the cruising range when I accelerated hard and ran it fast. (Since two-wheel therapy has been proven to be highly effective, I recommend kicking up a little gravel daily.)

There are several similar designs out there, but Zero models use second generation lithium-ion power packs that are monitored to deliver a combination of power and reliability. The Zero DS also has a dual sport suspension, and HB Performance single front and rear disc brakes with steel braided lines. The standard parts would be custom or premium aftermarket parts on most other bikes. The lightweight anodized 17-inch wheels and belt drive give the bike a unique appearance and handling.

I like dual sport bikes because I like options. This one has generous travel in the rear swing arm lightweight inverted forks. I’m only average in my off-road skills, but the DS was up to the challenge.

The powerplant for the Zero Motorcycle is an axial flux motor with forced air cooling. I had to look this one up. The stator (remember the rotor and stator in the homemade DC motor at the science fair?) and rotor face each other like hard drive discs on a computer. This setup allows for maximizing torque in a small package, and efficiency when maximum torque is not needed, like for coasting. Somehow, Zero has modulated the power so it accelerates evenly until it gets a few feet over the line, then kicks in.

Many agencies will see this product as a public relations tool. It’s electric and the agency can demonstrate it recognizes the need for green transportation. While this is OK, the true potential for the Zero DS is in enforcement. It can stealthily get right up on a call while the rider sees over the tops of vehicles during the approach. Officer safety is improved using invisible deployment, where the officer is on scene before the violator knows it. This is pretty easy on a street filled with residences. It’s tougher when there is some distance between houses and a road approach is obvious. The Zero DS changes the paradigm a little here.

This is one thing that has to change in the LE version of this product—it has to be capable of blacked out drive. Yet, it can sneak up on a crime in progress and negotiate just about any terrain you can put a motorcycle through.

I made it a point to cycle it several times day. I rode it hard for an hour, came back, and charged it. However, I only charged it for 1.5 hours and then rode again. When I returned it to my garage this time, I let it sit overnight. I cycled the motorcycle several times like this. It still gave me full-service, even if I charged it from a “half tank.” If I interrupted the charging after only an hour, it still gave me about 3/4 capacity and service.

There were a couple of times where I had an opportunity to really test the bike’s handling features. First, a vehicle pulled out in front of me while I had it completely throttled out. It braked evenly, without brake dive.

Another time I was making a turn in front of traffic at an intersection when I discovered the evidence of a major engine blowout with at least 100 feet of the oil slick that covered more than half the road. I was already into the turn when I realized I had no traction. I put my foot down and my foot slid on a sheet of oil. Since I was headed for traffic in the other lane I got back up on the peg and accelerated out of the turn, riding the bike. I would say this bike has ideal handling.

The engine has a high-efficiency forced air system underneath the saddle. When one initially turns the key, the fan starts up—the Zero version of “powering up.” This whisper, by the way, is as loud as it gets. I don’t completely understand the technology, but forced air raises the efficiency of the motor and increases its longevity. Whatever it does, the direct drive creates responsiveness at the twist of the wrist that rivals most midsize motorcycles. This kind of surprised me, because when one initially throttles this bike it appears as if it was going to start up gradually. Having kept up with a few of those noisy road bikes at intersections, I can attest to its road worthiness. It’s no quarter-miler, but it is more than satisfactory. I found that the lack of engine (or any) noise made the officer as approachable as a Segway rider. The difference being officers on patrol riding Segways can’t back up another officer on the other side of town.

When I let officers with motor experience check out the bike, I got a couple comments that startled me. The first was, “I’d make a traffic stop on this.” I experimented with this a little, simulating a dozen traffic stops from a city intersection. I definitely wouldn’t make routine stops in a 55 MPH zone (like I was doing), simply because one would be limited for a dozen or so stops. I would use this for campus or city park traffic enforcement, which is its ideal venue.

I rode the bike through city neighborhoods at night. This is Patrol 101: Invisible deployment is a component of officer safety. The Zero DS can jump curbs, grind through construction sites, ford streams and make less noise than a mountain bike. If the call is a high stakes in-progress incident, this vehicle can be on top of it before anyone even knows about it.

The police package should include complete blackout, including the charge indicator LEDs at foot level.

The Zero DS advantage

Anytime an agency would use bicycle patrol, the Zero DS has the edge. The motor can roll along at a walking pace, about 4 to 5 mph, which is hard to maintain on a bicycle. If needed, 65 mph to the hot call is doable. I rolled the DS through a city park, over the grass, without damage to the lawn, at about 40 mph, which is a tactical advantage over any bike patrol.

Anytime an agency would need stealthy special enforcement for the likes of business and bar checks, the DS can negotiate traffic, alleys and even stairs, just like any “enduro type” of motor patrol. I can think of a couple of crank lab cases that would have been easier with the DS.

Its rider can have a special assignment for a city or county park, or sport complex area where the assignment mixes public enforcement and public service. I can think of several parks where an electric vehicle would be the undisputed champ for patrol. I’d actually like to see this product become a patrol vehicle in our national parks.

I spent a lot of time in the general vicinity of California State University Stanislaus. CSU Stanislaus is enjoying its second year on the U.S. News and World Report Best Colleges ranking, and the Princeton Review Best Colleges ranking for the sixth year. For me, it was the ideal testing area because the medium-sized campus is right in the middle of a medium-sized city; on the campus there isn’t a building entrance or dormitory more than a few minutes away for a centrally located officer traveling the posted speed limit.

Does the Zero DS have a down side? It does. This is a second generation power pack, and I think a 58-mile limit keeps it within city, park or campus limits. But the technology is only getting better, and Zero is on the cutting edge here.

I think Zero Motorcycles Inc. holds the key to a future of electric patrol.


Lindsey Bertomen is a retired police officer who teaches at Hartnell College in Salinas, Calif. He welcomes comments at