Hi-Power Cycles (HPC) is a small outfit in Southern California who truly believe in the mettle of electric bikes. HPC sells most of their e-bikes to commuters, but the build kit we chose for this bike is designed more for off-road use. Everything from the full-suspension design, trail geometry and powerful brakes are designed to work well on the trail. In fact, if you stripped the battery and oversized hub off this machine, it would look like just another mountain bike.

PLASTIC OR CANVAS?

Clearly, the one thing that sets the HPC apart from most other e-bikes on the market is that they house the battery in a frame-mounted bag. Odd but effective. As for the rest of the bike, the HPC is built off a standard aluminum, full-suspension mountain bike chassis with 4.7 inches of suspension travel. Aside from the power train, the components are exactly what we’d expect to find on a $1500 to $2000 unpowered bike. While we chose the most affordable build kit for the actual bicycle parts, HPC also offers several options, including top-notch builds that can match any trail rider’s dream spec.

HPC builds their bikes with your choice of three different motors. We chose the highest-torque motor, dubbed the Striker. This motor gives up a little on top speed in exchange for low-end torque, a feature we found very helpful on steeper and more technical climbs.

The power source is a 2800-watt system (an upgrade from the standard 1000-watt motor) that runs off a 63-volt battery pack (another upgrade) housed in the frame bag. The bike as a whole is then controlled via an optional Cycle Analyst LCD diagnostic computer mounted to the handlebars for easy access and feedback while riding. The bike also features a nifty regeneration mode, which recharges the battery using the energy that the brakes would normally dissipate.

Unlike many e-bikes, the HPC is throttle control only. There is no pedal-assist function where the bike senses pedaling or torque and automatically provides assistance. You can still pedal, of course, but if you want any power assist, you have to turn the throttle open only until you feel as much aid as you want.

HOW DOES IT PERFORM?

HPC offers a variety of charging options. Our battery took about six hours to fully charge with the standard charger. Upgraded chargers allow the battery to fully charge in two or three hours. You can even choose a foldable solar charger if you do your riding off the grid. Our bike had an upgraded 63-volt battery rated at roughly 12.5 amp-hours. Monitoring the amp-hour usage is the only way to know how many electrons are in the tank; otherwise, you are just playing the e-bike version of Russian roulette. HPC fully realizes the importance of that readout, and they have the computer set to alternate between mph and amp-hours on the main readout. With a fresh battery, riders can expect to climb even the steepest climbs without using the pedals. We frequently used a brutally steep, paved road to a local water tower to judge the climbing ability of different bikes (and riders). The HPC never dropped below 19 mph without touching the pedals.

Despite having more power than your average e-bike and many small motorcycles, the HPC still relies on a direct-drive hub motor, and it does not like to be loaded hard or lugged down. Do so and the engine can protest with odd noises. If the hub is hot to the touch or the machine is audibly protesting, you need to pedal harder. We encountered a long, rocky climb with abrupt, rocky and choppy switchbacks that limited any speed, and while the HPC still dominated it, the bike was obviously working hard and the hub was heating up. A normal street-legal bike we had with us used half of the available battery charge on that single hill of less than a mile.

TOO MUCH POWER?

Still, the HPC is so powerful that we used the computer to dial the peak amps setting way back when we rode with other e-bikes or when we were near any other trail users. At full power, it simply does not act like a mountain bike, and we didn’t want to earn any ill will with other trail users. In fact, for normal trail use, we generally dropped the amp level to 20 or 25 amps and had no trouble hanging with other e-bikes at that level, and battery usage dropped so we had more range.

When you max out the bike at full power, pedaling becomes pretty superfluous. Throw in a lot of climbing with no human assist and you can kill the battery in 12 miles. Dialing the power back and pedaling more will greatly extend that number. Fortunately, the on-board computer allows you to limit the amps being delivered to the hub. Riding at lower levels forces you to pedal, and you just have to be disciplined enough to not run it wide open. Trust us, it’s not easy because it is really fun at full power.

The other time you need to go into the computer is when riding on the street. At full power the HPC isn’t legal on the street as a bicycle. To be legal, it must be limited to 750 watts and 20 miles an hour. It is easy to make those changes, and it is legal to pedal faster than 20. Even with the power turned to legal settings, the bike still zips along well. If the terrain is mild, you can easily ride without pedaling if you don’t mind using up the charge faster. With minimal assistance mode, this bike will run up to 30 miles with just enough juice to help you along. This bike is actually a lot of fun as a commuter or runabout, and we found ourselves looking for chances to run quick errands on the bike. The option to forget pedaling makes it a fun and easy way to leave the car at home for short trips.

Don’t overlook the chance to regenerate power when riding a bike like this. We found ourselves running low on battery power several times and hoping we wouldn’t have to pedal a 65-pound bike home. On several occasions, though, we completely killed the battery, only to regenerate on a steady descent for just enough power to get home. Touching the rear brake lever engages the regen before the brake starts in. The regen function acts as a brake, and it easily slows you on a long or steep descent. Using your power wisely is critical to get the most fun out of any electric bike, and the regeneration option makes that easier.

ON THE TRAIL

Since the rear wheel weighs about 15 pounds more than that found used by a typical mountain bike, it works as a pile driver over rocks and roots, meaning the bike is much more susceptible to rear pinch flats. HPC combats that by installing a super-heavy-duty, thick downhill tube in the rear wheel. It recommends 55 psi as well. We opted to risk a flat in the name of traction and ran 35 to 40 psi in the rear off-road and 40 or more on pavement. Still, do yourself a favor and ditch the Kenda Small Block 8 tires for something more robust. A pair of Kenda’s Nevegal tires would suit this bike better.

We chose the entry-level suspension package, including a RockShox XC-32 fork. The fork did its job dutifully, but a more robust fork with improved damper control, like our new favorite from the RockShox line, the Pike, would really make this bike come alive. We tuned the clickers and sag on the RockShox Monarch RL shock, and we were able to find a setting that worked fine for all the conditions we encountered.

The battery pack tucks neatly in the under-the-top-tube bag, and we were very impressed with how well HPC keeps it from contacting the rider when pedaling. For off-road riding, though, the mounting system still needs some refinement. The battery slides around in the pack and makes a great deal of noise when the trail gets rough.

BUYING ADVICE

We were skeptical at first, thinking the HPC would simply be a dumbed-down motorcycle, but after just a few rides, we realized the HPC is different than that. For many riders, the ride is not about suffering, sweating and proving themselves. They want to experience the trail and don’t care about beating it. It’s a way for riders to get out and experience mountain biking in terrain they otherwise would never be able to access because of fitness or physical limitations. It’s a great way to rip a quick after-work ride when time is short. It’s also a fantastic way to leave commuter traffic in the dust, so long as your work is closer than 15 or 20 miles away.

Specs

MSRP: $4400 (as tested)

Motor type: HPC Striker, 2800-watt, high-torque, direct-drive hub motor

Battery: 63V 12.5Ah Li-NMC high performance

Battery life: 3–4 years

Charge time: 4–6 hours

Controller: HPC Crystalyte

Top speed: 20 mph assisted (rider weight, rider input and terrain contingent with street settings) 30-mph-plus off-road at full power

Range: 15–30 miles with normal pedaling

Drive: SRAM X7 3×9

Brakes: Tektro E-Comp

Wheels: Alex Supra/Weinmann XM25

Tires: Kenda Small Block

8, 26×2.1 inch

Controls: Cycle analyst display

Fork: RockShox XC-32 fork

Shock: RockShox Monark RL

Frame: 6061 aluminum tubes and cast parts

Cranks/pedals: Truvativ E400/Wellgo flat

Weight: 65 pounds (large)

Sizes: 17, 19, 21 inches

Contact: (818) 734-1600, www.hi-powercycles.com

This review appears in the April 2014 issue of Electric Bike Action Magazine. To order a copy or start a subscription, call (800) 767-0345 or click right here.