- A stylish cruiser style ebike with excellent weight distribution available in high-step or step-thru frames but only one size ~19.5"
- Unique "upside down" motor mounting design improves ground clearance, quality Samsung battery pack, one year warranty
- Relaxed upright position, comfortable oversized seat and ergonomic grips, feet-forward bottom bracket reduces leg chaffing
- Mostly available online so there will be some assembly required, shipping is ~$150, I like that both wheels have quick release
Biktrix launched its first electric bike in November 2014 on Kickstarter; it was called the Juggernaut and offered fat tires on a sturdy high-step frame for a fun experience on sand, snow or trails. The Stunner is their second model, leveraging the same motor but a smaller battery pack it’s capable but optimized more for neighborhood or urban riding. It’s a cruiser style electric bike with a plush oversized saddle, integrated seat post suspension, swept back handlebars, ergonomic grips and a feet-forward bottom bracket that allows the seat to ride lower and also reduces inner thigh chaffing (due to the oversized saddle). Cruiser bikes are great for easy relaxed riding, your arms don’t have to reach out so far and your back and neck aren’t slumped over so they don’t get as sore. The big downside is usually limited gears, lack of suspension and increased weight. I was impressed with the Stunner because it’s lighter than many of the other cruiser electric bikes I try out at just ~50 lbs and I love that it comes in both high step or low step. I actually weighed and measured both and they were strikingly similar… This isn’t a case where the high-step is larger… There’s a lot you can adjust here for proper fit including the seat post height, stem angle and handle bar angle though you will need tools for the later two. Because this is a centerdrive powered ebike both wheels are able to use quick release skewers which is handy for changing flat tires, storing the bike or transporting it. All in all, I was very impressed with the choices Biktrix made to keep this thing cheap while still delivering a great ride experience. The V-brakes work fine, seven speeds is enough (even though the derailleur is entry level) the lights are handy (even though they aren’t wired in) and there’s mounting points for fenders and a rear rack. I also really like the colors they chose and the little extras like the reflective sidewall stripes on the tires.
Driving the Stunner is a 500 watt nominal, 750 watt peak mid-drive motor from 8Fun. I’ve reviewed this motor on its own here but some improvements have been made to the Biktrix version including better power activation and durability. Biktrix actually worked with the firmware a bit to optimize it and it felt very smooth and responsive during my test ride. Instead of powering the wheel directly like hub motors, this centerdrive pulls the same chain that you do as you pedal. In so doing, it leverages the seven speed cassette in the rear allowing it to operate more efficiently. Basically, this motor will climb better and go further than an equivalent hub motor and it keeps weight low and center on the frame instead of at the rear. Overall, the frame is very well balanced and sturdy feeling (though the step-thru version does flex a bit more). One thing that delighted me about the Stunner is how they chose to mount the BBS02 motor… it’s upside down! Most of the time these motors hang down and forward but the custom feet-forward design on the Stunner models let them flip it and this improves clearance while offering increased protection for the casing. Very cool… The motor can run in two different modes (throttle or pedal assist) and I felt like the response time in assist was very good. If you really need to stop, both brake levers have integrated motor cutoff switches so pulling them will cut power. The motor uses a cadence sensor so it’s responding to movement and not force which is nice if you’ve got sensitive knees or just want to get some movement vs. strenuous exercise. That said, it might not get the same kind of range that a torque sensing system would offer.
Powering the Stunner is an average sized 36 volt 10.4 amp hour battery pack that should offer upwards of 20 miles per charge… depending on how you ride, the terrain, even the wind. The cells inside are made by Samsung, a reputable manufacturer, and are warrantied for 800 cycles (but should last much longer). You can help extend their life by storing in a cool dry location and leaving the pack at ~50% capacity when being unused for extended periods. This helps to reduce strain. The batteries shown in the video review above are different because those were demo bikes and the final designs were still being finalized. In short, you can expect a locking, removable pack with an integrated power level indicator. It sounds like you won’t have to turn the pack on/off separately from the main console which is nice… and I noticed that Biktrix was using three mounting points for their battery bracket which increases strength. That’s the thing about this bike, in some ways it feels like a converted bicycle because you can buy the BBS02 yourself and convert your own frame if you’d like… but then again, they’ve customized the firmware, reinforced the battery mounting plate and even run the wires through the frame. I think you’d be hard pressed to find a frame that let you do the upside-down motor thing and considering the relatively high price of the BBS02 motor plus a quality Samsung battery you’d probably spend close to what this thing costs and not have the same sort of warranty support.
Operating the Biktrix Stunner is fairly simple and very standard. I’ve seen similar Bafang LCD displays on other electric bikes and they tend to hold up well. Once the battery pack is charged and mounted to the frame you can switch on the display by pressing a rubber power button on the remote button pad near the left grip. This pad is reachable but a little further away from the grip than normal due to the oversized cruiser handlebars. Once activated, the display console comes to life showing battery level, speed, assist level and a few more readouts. You can cycle through max speed, average speed, odometer and trip distance by pressing the power button again (and hold it to turn the bike off). You can also go into the settings and choose from either 3, 5 or 9 levels of assist. The additional levels don’t offer more power, they are more like finer increments offering more choices so you can find a perfect speed instead of going from low, medium and then high with the three level configuration. Physically speaking, the display can swivel forward to back to reduce glare if not overtightened but it is not removable. Because the bike is predominantly sold online you’ll have the opportunity to set things up just how you like them (or work with a local shop to do so upon arrival). While we’re on the topic of tightening… keep in mind that the adjustable stem used can begin to rattle over time if not kept tight, especially if you ride off-road at all or go off curbs. That’s just what happens with this style of stem. As for the right side of the bars, you’ve got an ergonomic grip, trigger throttle and the oversized index shifters by Shimano. Everything works but the grip has been shortened a bit so the throttle could fit and this could be an issue for riders with larger hands. The grips are basic rubber and don’t have lockers and the brake levers are also pretty basic but that keeps the price lower. While we’re talking about the display and control systems, note that when ordering the Stunner or their fat bike the Juggernaut from Biketrix you can request that they “unlock the throttle” meaning that you will be able to twist and go at pedal assist level zero and override all other levels beyond their default setting. This changes the bike from a Class 1 to a Class 2 and may limit where you can use it (some mountain bike trails prohibit throttle use). Regardless of this throttle unlock setting the bike will still only go up to 15.5 mph or 20 mph (depending on your geography) but the throttle will be active at all times when the system is powered on. I personally prefer this type of riding but it does increase the risk of accidental activation when mounting or transporting. Keep this option and its potential consequences in mind when ordering.
Overall I was very impressed with the Stunner but a little surprised with the ~$2k price point being quoted. I was told the same price for the Juggernaut but saw that it is much cheaper on the website… perhaps this is an anchoring technique used to make the bike feel affordable. Even at this price, you’re getting a solid bike with a decent warranty in some nice colors (the pearlescent paint is cool in white or gray). Mid-drive ebikes tend to create more strain and wear on chains, cassettes and derailleurs but the 36 volt battery (and I’m assuming lower amperage) aren’t driving this bike as hard as the Juggernaut which has a 48 volt pack. While you don’t get a suspension fork here, the frame stays light and the seat and suspension post keep it relatively comfortable. The lights aren’t wired in but at least you get them and the reflective tires are great. There aren’t disc brakes here but for around-town types of rides you don’t really need them, the stopping power is fine and rubber pads tend to be easier to change. No fenders or rack but you’ve got the mounting points available and this lowers the price (and probably saves materials for people who didn’t want them anyway). When choosing fenders just make sure to consider whether they will collide with the V-brakes (these ones seem to suggest they would work), the rack should be no problem and something like this would probably work fine.
- The battery pack is mounted with three bosses instead of just two (like most aftermarket kits), this will add strength and durability
- The demo bikes didn’t have bottle cage bosses but I’m told the final build will, this is great for carrying along drinks, a mini pump or a lock without having to wear a backpack or add a rack
- Comfortable seating position, you get an oversized saddle with suspension seat post and a bottom bracket that is mounted further forward so your legs won’t chaff against the seat when pedaling
- Handlebars are oversized and swept back so you don’t have to lean forward (avoiding a sore back and neck), I like the ergonomic grips but they don’t have lockers and are kind of basic
- The motor has been mounted “upside down” compared to what I usually see but this actually offers better ground clearance and improved protection from rocks, curbs etc. also, I like that the power cables are internally routed and kept out of sight
- Because this ebike uses a mid-mounted motor they were able to use quick-release skewers on both wheels! This means you can more easily change flats or do wheel maintenance on the trail or break the bike down for compact storage and transport
- You can request that Biktrix unlock the throttle so you can use it in level zero and override assist, the stock setup only lets you use throttle power when in pedal assist mode and only up to the level of pedal assist you’re currently in
- Front and rear lights are included with the bike but they run off of separate batteries… it’s nice to have lights and the front one is mounted pretty well so I view this as a pro though it would be nice if they were wired in
- Pedal assist is smooth and responsive (the cadence sensor is built right into the bottom bracket/motor area)
- In order to fit the large shifter and trigger throttle near the right grip they chose a shorter grip and this means you don’t have as much room to hold on (might be a bother for people with larger hands)
- Because this ebike is more of a cruiser and offers large swept-back bars I noticed the independent button pad that mounts near the left grip doesn’t quite reach (the wire wasn’t long enough on the bike I tested) so you have to reach your fingers further to change assist levels when riding
- The adjustable stem helps different sized riders fit the bike (since the frame basically only comes in one size ~19.5″) but it seems like these types of stems can get loose over time, especially if riding off-road so keep an eye on it and tighten if it starts to come loose
- The two bikes I looked at were prototypes (very close to production) and had different battery packs that had to be powered on independently from the main display… I’m told that the final build will not require this extra step
- I noticed that there wasn’t a slap guard on the right chain stay, this means the chain could bounce into the frame and chip it if you’re riding on rough terrain, consider adding one like this yourself
- There is no shift sensing built into the mid-drive motor on this ebike which means the chain and gears can experience more force and wear if you don’t shift smoothly and carefully (ideally when you are not activating the motor)