- A full suspension, cross country style, electric mountain bike made just for the ladies with shorter reach, available in two smaller size options, features a turquoise fuchsia colorway
- Sturdy Suntour XCR 34 air suspension fork with remote lockout for easy transitions from rough to smooth sections of trail, tapered head tube provides compatibility for even nicer forks
- The 10-speed Shimano Deore drivetrain is pretty good and comes with a Shadow Plus one-way clutch to secure the chain on rough sections, the alloy chainring guard reduces the potential for drops
- Bosch CX high-torque motor is powerful, responsive, and now offers eMTB mode that acts more like a torque sensor so you don't have to press buttons when riding
The variety and price range of electric bikes has grown significantly since I entered the space in 2012. BULLS is contributing to this diversity of products by offering the Aminga TR 1 in the United States starting in 2018! This is a women’s specific electric mountain bike, designed specifically for cross country and trail riding. It provides plus air suspension that can be sagged (pressure adjusted) for a range of body weights, is featured in two sizes (small and medium), and comes with a shorter stem because ladies tend to have shorter arms than men. Of course, the most obvious nod to the finer sex is the color scheme with teal or turquoise and fuchsia paint. But don’t underestimate this ebike, because it’s very capable and built around some of the latest design fundamentals such as stiff thru-axles, wider “Boost” hubs that offer a sturdy spoke bracing angle, and extra wide plus sized” tires that increase traction, float and comfort. It’s running one of the most widely recognized, highest quality drive systems from Bosch, and it comes with a two year comprehensive warranty and nation-wide dealer support. Of course, all of this contributes to a higher price tag and the $4,299 MSRP is on par with the other bikes from BULLS that seem to be colored and designed more for unisex or male riders. The price might actually be a little on the high side for the Aminga because the volume sold could be lower. I’m just guessing here… check out all of the other BULLS models and my reviews to decide for yourself. The Shimano Deore derailleur is good, but a step below SLX or XT, and the SR Suntour suspension offers open or locked vs. a medium setting as some of the RockShox and Fox models provide.
Driving the bike is a high-powered centerdrive motor from Bosch called the Performance Line CX. It’s a mountain bike specific model with a higher torque rating of 75 Newton meters, a sportier quicker feel, and a special drive mode called eMTB that offers low to high output based purely on pedal power vs. making you click up and down with a control pad. The major trade-offs are that it can burn through battery capacity a bit quicker and produce more noise. A lot of this depends on which level of assist you choose to ride in, and I noticed that Paula (the young female rider in the video review above) was struggling a bit with the higher levels of assist. It was causing her to surge forward a bit and then cutting out because her pedaling wasn’t super consistent and we were on flatter terrain. If you stick to the lower Eco and Tour settings, this motor can deliver outstanding range and feel very smooth, but eMTB mode is also smooth and quiet if you aren’t pedaling hard. The motor is empowered by how you pedal and measures the rear wheel speed, pedal cadence, and pedal torque over 1,000 times per second. It even senses when you’re shifting gears in order to ease back and reduce drivetrain wear. Imagine your leg forces plus a motor that’s rated 250 watts to 500+ watts combined to pull on a chain, through the rear sprockets, and on that derailleur. The Bosch motors are unique in offering this shift detection, and it’s software driven and imperfect in my experience but much better than nothing. For best results, I still ease back on my own pedaling force when shifting gears. The motor can operate at up to 120 RPM (pedal strokes per minute) which is higher than some other mid-drives and this means you can spin faster with support vs. having to shift down to maintain support. It’s great for someone like me with a sensitive knee and road cycling background :)
Powering the Aminga is a Bosch Powerpack 500 which is the premium pack right now, offering 25% more capacity than the older Powerpack 400 with only ~0.5 lb increase in weight. In fact, the battery pack looks the same as the older Powerpack and uses the same mounting interface, so it’s backward compatible. What I really love about this pack is how easy it is to charge, using the included fast 4-Amp battery charger. You can charge it on or off the bike, and I usually remove it to reduce overall weight for lifting, wheel service, and transport. The pack locks securely to the frame but let’s say you’re commuting to work with this bike during the week… you can take the pack off and bring it into the office for a refill before going home. And, if you want to really protect the pack, I suggest storing it in a cool, dry location because extreme heat and cold can degrade Lithium-ion cells. Note the white stickers that have been placed along the battery pack and parts of the motor to help them blend in. I love how BULLS has styled their downtube to bring the battery down while angling the motor to raise ground clearance and help it blend into the frame. This is a beautiful looking e-bike and all of the electrical system weight is positioned low and center, right where you’d want it for optimal handling. There’s enough room for a 120 mm suspension fork and rear suspension, but there wasn’t space for bottle cage bosses or for the seat post to slide down super far. I actually cut the end of the seat post off so the saddle could go lower for Paula. It’s not a huge deal to do, just get a hacksaw and then sand the end when you’ve cut part of it off… be sure to leave enough post so that you can stick some in for a sturdy hold with the seat post collar. As someone who mountain bikes a lot, I have become a fan of seat post droppers (which let you raise and lower saddle height with the press of a button) and Race Face sells a 30.9 mm option that could be installed on this bike. Note that the front shock can be locked out directly from a switch at the handlebar and the rear has two settings for open or closed that are activated by a little blue lever you can reach while riding. The rear suspension is actually pretty nice, with a two-pivot action which keeps the wheel vertical vs. rotational and helps to keep the chain length constant and improve braking consistency.
Operating this electric bike is pretty easy once you’ve charged and mounted the battery pack. Just press the little black power button at the top edge of the Bosch Purion display panel. This display is nice because of how compact and simple it is but you do sacrifice some functionality, removability, and accessory charging options that the larger Bosch Intuvia display offers. For mountain biking models, BULLS has moved almost completely to the Purion and I think it’s partially a cost savings thing. The display is still relatively easy to reach, glows faintly in the dark, and has incorporated walk mode (which some other brands like Trek have disabled). You can activate walk mode by pressing the black button on the bottom of the display and then holding the plus button. It’s a neat feature for climbing steep hills (when you might not feel comfortable trying to ride up or maybe you tried and had to step off to avoid tipping). There are two more buttons on the display, plus and minus, that let you cycle through the four levels of assist, or you can pedal with the motor completely off and use the display to show your speed and activate lights. The Aminga TR 1 is compatible with MonkeyLink front and rear lights and fender options. There are special interfaces on the stem and seat post clamp which are pre-wired to work with these branded accessories… and I love that! But the headlight system isn’t adjustable in terms of angle, so you can’t shine it up or down depending on how you like to ride or where you are at. Anyway, to turn on lights, just hold the plus button on the display for a few seconds and an icon will appear. The minus button has a couple of extra features too, if you hold it down, the display cycles from assist level to trip meter, odometer, and range estimate. I love range estimate because it’s much more interactive and precise than the simple five-bar battery infographic at the top of the display. With range estimate, you can click + or – and cycle through assist with realtime readouts of how far the bike thinks it can go before the battery will completely run out. This range estimator uses your last mile of activity, the battery charge level, and the level of assist in use to dynamically update in realtime. The final secret feature in the display is that if you hold minus and then tap the power button, you can change units from miles to kilometers and back. This was a big hit with the family shown in the video because they are from Spain and were more used to Metric than Imperial.
All things considered, the Aminga is a trail worthy electric mountain bike with a few minor tweaks to make it comfortable and attractive to women. The shorter stem, ergonomic grips, ladies saddle, and color choices all contribute to make it unique but the drivetrain and motor are exactly the same as many of the gender neutral or male models designed for similar use. I had a blast testing it out and Paula eventually got the hang of the dynamic drive options and sensitive torque response in higher levels of assist. We didn’t really do this ebike justice and it’s way more capable than an around town type of bike, I’m not sure Paula could really appreciate the quality full suspension components, plus sized tires, and Boost with thru-axles because the terrain we tested on was so tame… but it still performed well. The bike does have provisions for a rear kickstand but no rack or bottle cage options so I’d suggest getting a hydration pack. The cockpit is clean and in eMTB mode you only need to think about what gear to shift into and how hard to pedal vs. what level the motor should operate at. Again, it’s neat that you can lower the tire pressure (or run tubeless for the lowest pressure options and reduced weight) and sag the suspension to fit your body weight. I’d like to say a big thanks to Paula, her sister Carla, and father Victor for helping out with this review and to BULLS for partnering with me on this post. I got to review many of their models back to back this year which provided more insights and details, which hopefully makes it a richer experience for you. Comments and feedback are always welcome below and in the forums!
- One of the few women’s specific electric mountain bikes I have seen in the USA, and this one offers high quality components and a top-of-the-line drive system from Bosch
- The Bosch Performance Line CX motor is one of the most responsive, high-torque, and reliable motors on the market right now, it’s perfect for cross country and mountain biking because it can produce up to 75 Newton meters of torque vs. 50 Nm or 63 Nm on the standard Performance Line motor
- To make their drive system less distracting for trail use, Bosch offers eMTB mode for the CX motor, you get there by arrowing up (between Tour and Turbo) and it offers a full range of power without clicking any buttons, it’s more of a torque sensor response and it works surprisingly well when pedaling gently or hard… it responds
- The Shimano Deore 10-speed drivetrain offers good range for cross country and trail style mountain riding and I love that it comes with the Shadow Plus clutch for snappier shifting and reduced chain slap
- With all of the Bosch motors, there’s a shift detection software system built in that can sense that gears are being changed and it tries to ease off of the power to reduce strain on the drivetrain, it’s not perfect but it’s better than nothing, the only other drive systems I know of which do this are some Impulse motors and some customized Bafang systems which are usually installed as kits
- Battery and motor weight are kept low and center on the frame which improves stability and handling, it also reduces unsprung weight compared to a hub motor since this is a full suspension ebike
- The Aminga TR 1 comes with wider “Boost” hubs that improve wheel stiffness and strength by widening the spoke bracing angle and the 2.6″ wide tires are considered “Plus Sized” which offer more air volume for comfort and larger contact patch for control
- Thru-axles on the front and rear wheel provide strength and the front skewer is setup with quick release which makes the bike easier to service or break-down for transport/lifting
- The battery pack can be charged on or off the bike (for convenience, battery protection, and reduced weight for transport), I recommend storing packs in a cool dry location to keep the cells healthy
- The locking core used for the battery pack is made by ABUS and comes with a card that has a code written down for you to use when ordering other locks (chains, u-locks, folding locks) so you don’t have to carry multiple different keys
- Not every electric bicycle company has mastered the design aesthetic of integrating the Bosch motor as well as Bulls in my opinion, look at how it’s angled up and incorporated into the seat tube and downtube to raise ground clearance and just not stand out as much
- I’ve become a fan of the MonkeyLink magnetic clips for adding a headlight and rear light or fender, it’s cool that this bike comes with some of those parts, even if you don’t use them
- This is the only BULLS electric bike being brought to the US for 2018 and it strikes a balance between affordability and higher-end specs, some people felt that the Deore derailleur should have been SLX or XT but at least it has Shadow Plus clutch, I think it’s pretty good but you could always choose one of the “guys” bikes even though they look more masculine in terms of colors and designs
- I’m not a huge fan of the Bosch Purion display panel because it cannot be removed, you can’t angle it without tools (to reduce glare while riding), it doesn’t have a smartphone app, you cannot charge accessories with the Micro-USB port on the side (that’s just for diagnostics), and it doesn’t offer as many readouts as the Bosch Intuvia (such as shift recommendation, timer, clock, max speed, average speed), but some shops will help you upgrade if you’re willing to pay ~$150
- One relatively minor trade-off that Bosch has made with their Performance Line motors is to incorporate a reduction gear so when you turn the crank one time the chainring actually goes around 2.5 times, and this does create some mechanical friction, the upside is improved response, improved efficiency, and improved chain retention, one downside is that it puts the chain very close to the chainstay which could result in contact and chipping of paint
- Because this frame was designed for full suspension, comes in smaller sizes, and has a downtube-mounted battery pack, there wasn’t room to mount a water bottle cage, consider a saddle adapter like this or maybe just a hydration pack like this
- Depending on your inseam length and comfort with saddle height, you might have to cut the seatpost (with a hacksaw) to get it low because the rear suspension interrupts the seat tube, I cut it for this review because Paula wasn’t super comfortable with a high saddle
- Both suspension systems offer locked or unlocked, sometimes it’s nice to have a middle “medium” compression setting… but at least they are both air and can be sagged to a range of rider weights and they also have rebound adjusters