2015 Polaris Terrain Review


Technical Specs & Ratings





Class 2


Front Suspension



Mechanical Disc



264 Wh

264 Wh

52 lbs / 23.61 kgs


Neco 1-1/8"

Zoom 31.8 mm Barclamp, 75 mm Length, 17-Degree Rise

Zoom MTB

Velo Ergonomic with Lockers



Velo Plush Sport

Wellgo Aluminum Alloy Platform

Mechanical Disc

Tektro Aquila Mechanical Disc with 180 mm Rotors, Tektro Levers with Integrated Bell and Motor Cutoff Switch


Video Reviews

Written Reviews

UPDATE! It appears that Polaris is no longer working with the manufacturer who designed and built these electric bikes, but that company is now selling their own line as PIM (Power in Motion) and you can connect with them through their official website at www.pimbicycles.com to possibly get replacement batteries, chargers, and other hardware. The following review stands on its own and represents the Polaris bike as I experienced it at the time.

The Polaris Terrain is a hardtail electric trail bike with a proprietary drive system, purpose built frame and a solid warranty. While it’s a bit heavier than some other electric mountain bikes, it benefits from a rugged gearless hub motor that offers an impressive 750 watts of power (most average ebikes offer ~350) and is capable of regenerative braking and two levels of power regeneration for coasting down hills or increasing resistance for working out on flats. With a brushed aluminum finish that won’t show nicks and dings, a mid-step frame that’s easier to mount but very stiff thanks to large reinforced tubing and a solid two year warranty on the electronics this is a solid bike. That said, because it’s limited to a single frame size and may be limited to Polaris outlets this ebike could be more difficult to find and fit. It also took me a while to learn and warm up to their drive system and the $799 battery pack replacement price also gave me second thoughts.

Driving this bike is an impressive 750 watt gearless direct drive hub motor located in the rear. Its peak output is actually closer to 1,000 watts which is incredible but that’s not the whole story… Being gearless, the higher wattage sort of makes up for mechanical advantages that a geared hub or mid-drive motor would experience. One advantage to the gearless drive on the Terrain is that it runs a bit quieter (though it still whirs at lower speeds when climbing). Another benefit is toughness, there are no gears inside making contact with each other, just magnets repelling. Toughness aside, the real advantage to a gearless direct drive motor setup is that you can use those magnets to recoup power with regenerative braking and that’s exactly what Polaris does here. Not only do you get regenerative braking (activated with both brake levers), but you also get two levels of regen mode which helps to extend range and means you can get away with a smaller, relatively lighter battery pack.

The battery powering the Terrain offer a solid 44 volts of power with smaller 6 amp hours of capacity. It uses light weight, long lasting Lithium Manganese cells and can be charged on or off the bike. This is especially useful when you transport the bike because it helps to reduce weight on the frame. They’ve designed the pack to fit right into the top tube on this model and it’s actually interchangeable with other second generation Polaris ebikes. You can even get a second pack to extend your range or balance charging when commuting (one at home, one at the office) but they cost a pretty penny at nearly $800. As you can see, the downtube is very wide and sort of overbuilt. This makes the bike a bit heavier but adds strength and stiffness which means the frame won’t flex as much when you really push the bike going off-road.

Operating the Terrain electric bike systems is pretty straight forward. You charge the battery, press the power button on the display console and the system activates. From here you can arrow up or down on the display to choose from 3 levels of assist or two levels of regen (perfect for coasting down hills or getting a workout). I’ve always been fascinated with regeneration modes on ebikes but the truth is, you don’t really get that much power back. The utility of the feature boils down to saving your wrists from squeezing the brakes constantly and offsetting some of the cogging and increased weight of a gearless motor. The handlebars and cockpit of this ebike are relatively straight forward with Tektro brake levers on both sides and a trigger shifter on the right bar. You get eight speeds to pedal with and that’s solid for climbing or cruising and fits the “value” setup of the Terrain. While we’re on the topic of value… the mechanical disc brakes used here can squeak a bit and require more energy to activate than hydraulic ones would. I also noticed that the trigger throttle (located on the left bar) worked best when it wasn’t pushed all the way forward. I like that this bike offers two drive modes (assist or throttle) but wasn’t always satisfied with the motor output. even though it sounds very large and powerful on paper, it sometimes felt sluggish due to the unique drive sensors. The BioSync cadence sensor used on the Terrain can actually sense when you shift gears by measuring the cable that activates the rear derailleur. It uses this feedback along with the chain speed (measured by the chain guide just below the chain stay) to activate and de-activate the motor. It’s a unique system that helps the bike respond more naturally to the gear that the bike is riding in but isn’t always the most satisfying and might take some getting used to.

The Terrain and other Polaris electric bikes received mixed feedback at Interbike 2014 where I first saw them. People weren’t immediately satisfied with the slower speeds when riding in low gears but I think they might have missed the point. If you’re riding in a crowd or trying to go slowly on a section of trail and therefor using a low gear, you don’t want speed. And especially when you’re climbing, it’s nice to have the motor focus on torque vs. speed. I get that, and between the throttle and assist modes offered on the terrain you have a lot of choices for how to ride. With a bit of practice and the proper expectations for what’s being offered here this bike can really shine. It’s still a bit expensive and heavy in my book but the suspension fork with lockout, ergo grips and padded saddle are great extras that demonstrate the commitment to a higher quality level than cheap imports. You really could use this as a commuter or trail bike and given the generous warranty and quality reputation of Polaris I think it could be a good choice.


  • Offers a trigger throttle on the left bar in addition to Evantage pedal assist and regeneration so you have multiple ways to use the motor and don’t have to pedal as with the higher end Polaris speed pedelecs
  • Suspension fork and larger knobby tires help to smooth out cracks and bumps, they make the bike trail or light mountain capable but there’s also a mounting point for a rear carry rack and a lockout on the fork so it could also work well for commuting or urban riding
  • Mid-step frame design is a bit easier to mount than traditional high-step but the frame still has a top tube and downtube and stays very rigid, it feels sturdy
  • Large 180 mm mechanical disc brakes offer great stopping power and the Tektro levers are upgraded to include motor inhibitors as well as a bell
  • The 650B 27.5″ wheel size offers good momentum and a higher attack angle for taking on roots, rocks and other rough terrain elements but is still nimble and won’t clip your toes as easily when making big turns
  • BioSync cadence sensor can detect gear shifting using an internal pulley, it uses this information to provide slow torque in low “climbing” gears and high speed in high “fast” gears
  • Reduced wear on brake pads and extended range thanks to regenerative braking, two levels of regen and automatic regen based on bike speed and chosen gear
  • Battery pack is beautifully integrated into the frame for improved balance and protection, locking and removable for convenient charging or reduced weight during transport (front wheel with quick release also helps)
  • Gearless direct drive motor is fairly quiet compared with a geared hub but does hum a little bit in the lower speeds (especially when climbing)
  • Wires are hidden on the frame but remain accessible for doing maintenance, the display panel and motor have modular disconnects for easy service and replacement if necessary


  • The Polaris Terrain only comes in one frame size which might make dialing in the fit a bit more difficult for short or tall riders
  • This ebike is havier than similar electric bikes I’ve tested that use geared motors vs. gearless but the weight is fairly well balanced thanks to the battery position
  • The battery pack offers relatively low watt hours and is very expensive to replace ~$700 though it can offer decent range thanks to the three assist levels and regeneration options
  • At times, this ebike can feel less satisfying because the power output hinges on which gear you’ve chosen to pedal with, it doesn’t provide that zippy feeling using the trigger throttle and you may have better luck not pushing the throttle all the way forward because it was cutting out during my ride test

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