2017 BULLS E-STREAM EVO 3 Carbon 27.5 Plus Review


Technical Specs & Ratings



E-STREAM EVO 3 Carbon 27.5 Plus


Class 1


Front Suspension



Hydraulic Disc



647.5 Wh

647.5 Wh

46.5 lbs / 21.11 kgs


STYX Chin Hau Tapered 1-1/2 to 1-1/8"

STYX Alloy, 7° Angle, (80 mm, 90 mm)

Low Rise, 740 mm Length, 25 mm Rise, 9° Bend, 31.8 mm Diameter

Ergon VLG-16828D3 Locking, Flat

STYX Aluminum Alloy


Selle Royal Seta M1

Wellgo C-128DU Alloy Platform, Cage Style

Hydraulic Disc

Magura Hydraulic Disc with 180 mm Rotors, MT-5 4 Piston Front and MT-4 2 Piston Rear, Magura MT Levers


Video Reviews

Written Reviews

There really aren’t that many Carbon fiber electric bikes… yet! It’s a combination that makes sense to me but is understandably very expensive. The Carbon fiber dampens vibration and decreases weight which is great for a platform which tends to ride further, maintain higher average speeds and be heavier due to motor, battery and control systems. The BULLS E-Stream EVO 3 Carbon 27.5 Plus is more than a mouthful, it’s a reasonably priced, beautifully designed hardtail electric bike that’s available in two frame sizes. It’s really an amazing e-bike, one that blends in with non-powered mountain bikes perfectly thanks to a compact motor and downtube integrated battery pack. Even the display panel is minimal but you aren’t required to reach down in order to change assist levels as you are with the Specialized Turbo Levo models, nor are you required to fret over a gigantic LCD display as you are with some of the older Bosch, Yamaha and Impulse e-mountain bikes. I like almost everything about it except for the lack of rack bosses at the rear end… because I love to commute with hardtail bikes like this. As it stands, you can add a Thule Pack’n Pedal rack and get pretty good utility without the side to side bumping that many beam racks suffer from. Perhaps Bulls did consider rack bosses but passed to save weight and improve strength of the frame? Amazingly, they did manage to squeeze in a set of bottle cage bosses on the seat tube and you can take out two screws from the battery interface and mount another cage on the downtube. That’s the way it should be in my opinion, so many ebikes forego bottle mounts all together and it’s not always clear why?

The E-Stream EVO 3 Carbon isn’t perfect, it suffers from the same issues as most of the other Brose powered Bulls models. Namely, the battery pack is a bit difficult to mount and dismount due to a key plus sliding lever maneuver. At least it’s secure and doesn’t rattle when riding… I also like the foam pad they mounted to the base for protection. Note that they key is directly in the path of the left crank arm so don’t forget to remove it before baking the bike up or jumping on for a ride lest you sheer it off. Other gripes include a finicky charge port cover, basic non-locking grips and the lack of shift sensing in the motor control system which could protect some of the chain, sprocket and derailleur wear. this electric mountain bike offers 22 gear combinations which is more than double what I see from competing bikes. That means more cadence increments and perhaps more comfort but also more shifting. The motor senses pedal cadence and torque though so it’s up to you to ease off before shifting in order to momentarily deactivate power and shift smoothly. The Brose motor itself is compact, relatively quiet thanks to a belt transition inside and extremely powerful (offering up to 90 Newton meters of peak torque output). Try not to be put off by the 250 watt nominal rating, it peaks closer to 530 watts. Ultimately, it’s efficient and that means longer rides and fewer stops for charging. Note that the motor surround is made of Carbon fiber and does not have deflector tape or padding like the battery. Be careful with it and consider adding some clear tape of your own to reduce nicks and scratches.

Powering the motor is an extra large capacity battery pack with premium Lithium-ion cells. It can be charged on or off the frame and uses the EnergyBus Rosenberger charging format. This means, if you trip over the cable it just pops out without bending pins and hopefully without knocking the bike over. The pack delivers 36 volts of power and 17.5 amp hours which is about 7.5 amp hours more than most electric bikes. Do note that the pack itself has two EnergyBus ports and you can plug into either one when charging separately from the bike (I double checked with the Bulls reps). Even though the pack can be tricky to put on and take off, I like that it’s possible because it weighs seven pounds and there are times (like the winter) when storing it inside away from the extreme cold could make a lot of sense. I might take it off when transporting on car racks as well, especially if there are multiple bikes which could add up and strain your rack or damage your car. Note that both wheels have quick release thru-axles and are easy to remove. The front is a 15 mm and the rear is a 12 mm both with Boost technology (basically they are slightly longer to improve strength and spoke angle).

Operating the bike is very straightforward once it’s fully charged. If you haven’t used it for a while, you might have to press a button on the downtube (which lights up a battery capacity indicator). This sort of primes the bike and allows you to press a second on/off switch along the top edge of the display console. I love how compact this thing is, it’s basically a large rocker button with a transflective display on top. You press down on the display to arrow up or down through three levels of assist. Along the side there’s a walk button and a light switch but this particular Bulls ebike doesn’t come with lights so you can ignore that. Just below the button screen portion of the control pad is a rubber plug protecting a Micro USB port! For me this is really cool because I like to ride with Strava and use GPS. Sometimes I also mount lights and being able to tap right into that huge ebike battery to keep my accessories charged on the go is very cool. So the display gives you speed readouts and a battery indicator with five bars, just like the downtube LED readout. It’s large enough to read the speed but you might end up “feeling” the other stats like which power level has been selected. There’s a tactile click as you press down and it’s nice to be able to do so without looking. The whole thing is small enough to evade notice from fellow cyclists but not so thin that it wouldn’t be impervious to damage during a fall… and it’s not removable. This means the sun, rain and vandalism could happen so consider covering it with your bike glove or just keeping an eye out.

The cockpit on this bike is well setup, it looks good and balances two shifters with a remote lockout lever on the right and the display control pad thing on the left. There’s plenty of space for your lights and other accessories but leaving it clean and clear is best for bumpy terrain. The Bulls E-Stream EVO 3 Carbon maxes out at 20 mph for the US version and is thus a Class 1 electric bike, allowed on more off-road trails than Class 2 or Class 3. Even though it still weighs ~46.5 lbs that’s ~4 lbs less than other premium hardtails I’ve tested. For someone who loves riding cross country and wants to go further, this would be an excellent choice. Bulls offers a five-year frame warranty with two years on the battery and motor. They’ve taken off in Europe and are two years into the US market now with a growing network of dealers. On the one hand, I wish it were full suspension but then for $4,600 and the lighter weight you get, I feel like the larger plus sized tires and awesome suspension fork would do a lot for comfort. I would consider a seat post suspsension myself and BodyFloat sells a Carbon fiber version so you could continue the theme of the bike. Big thanks to Bulls for partnering with me for this review.


  • The tires are a stand-out feature on this ebike, they offer improved traction through a larger contact patch, increased comfort due to more air volume, reduced deflection and slipping on rocks and other angular surfaces and provide great rolling momentum and gap spanning with the 27.5″ diameter size, they are also 2.8″ thick vs. 3″ on some other plus models and I think this decreases weight slightl
  • At 46.5 lbs this is a very light weight hardtail electric bike… especially when you consider the battery capacity at 647.5 watt hours, it’s tough but the Carbon fiber frame shaves the pounds off
  • I was really impressed to discover that the E-Stream EVO 3 Carbon comes in two frame sizes, while they’re both high-step (for strength) more riders should be capable of fitting comfortably, the top tube is angled down so stand-over height is maximized, even so I love that they were able to include bottle cage bosses on the downtube and seat tube!
  • You get 22 gear combinations on this bike which is more than double what I see on a lot of other e-mountain bikes, the setup is 2×11 with Shimano Deore XT Shadow Plus, most mid-drive electric bikes only offer one ring up front (shift carefully given the extra power)
  • Premium Magura hydraulic disc brakes with 180 mm rotors and a 4 and 2 piston setup (four up front to spread out the forces and improve cooling), two-finger levers with adjustable reach let you dial in your hand position and focus on maneuvering
  • Quick release on both wheels so you can transport the frame more easily (perhaps store it inside your car when parking), definitely pop the battery off to lighten it up if you’re using a hang style rack… front axle is 15 mm and the rear is 12 mm for increased strength and stiffness
  • Battery and motor weight are right where you’d want them… low and center across the frame, they also blend in visually and the battery has a foam pad liner on the bottom to protect from rocks and other obstacles
  • The Brose motor is super quiet and features a belt system between gear sets which reduces vibration, making it feel more natural
  • Beautiful paint with minimal decals (matching accents on the frame, fork and wheelset), cables are mostly internally routed for protection and improved aesthetics
  • Super high torque output for climbing, you get up to 90 Nm which pairs nicely with the lower gears, I haven’t had any issues climbing even the steepest terrain as long as I shifted appropriately
  • Wider 30.9 mm seat post diameter improved strength, consider swapping the post out for a carbon fiber BodyFloat for maximum comfort while still keeping it light… tighten the post down to reduce slip but don’t over-tighten and crack the tube
  • The charger works faster than most others I’ve seen, it’s a 5 amp battery charger that weighs a bit more at ~2.5 lbs but is still portable enough to come along in a backpack or something
  • Both wheels offer Boost which gives you 6 mm additional width in the rear and 10 mm additional width up front, this strengthens spoke angle and improves handling
  • The cockpit handlebar area is fairly clean considering you’ve got shifters on both sides and remote lockout for the suspension fork, I love their little transflective display button pad thing because it’s easy to reach and read but doesn’t stand out as “electric bike” or seem as vulnerable as a full sized mid-mounted display panel seen on a lot of other ebikes
  • They were able to squeeze a 6 Volt Micro USB port into the base of the control panel, this lets you charge a phone or other portable electronic device and tap into the huge primary e-bike battery, very cool and well positioned at the handlebar vs. down on the pack where you’d have to run a cable


  • Unlike the Impulse mid-drive, some Bafang setups and the Bosch Centerdrive these Brose motors don’t offer shift sensing and that means you’ll have to be extra careful not to stress the chain, sprockets and derailleur… The system measures pedal speed and torque very quickly so shifting can be done smoothly, it’s just more raw
  • I wish they included rack bosses at the rear because I love to ride hardtails like this during the week as an adventure commuter but I see how that might compromise frame strength or add a lot to the price, consider a beam rack or the Thule Pack ‘N Pedal
  • They key slot for removing the battery pack is very close to the left crank arm which could be vulnerable… you don’t have to leave the key in while riding or anything, just take care when adjusting, same thing with the charging port but it’s magnetic so it won’t get bent pins or anything
  • I would like to see an improvement in the charging port cover, it took me several minutes ad a bit of finessing to get it properly seated on several of the Bulls demo bikes and that’s no fun (considering you probably charge the thing daily), it’s important to keep the interface clean and that cover should fit easily and seal completely in my opinion
  • Actually taking the battery off can be tricky without a second person there to hold the bike… there’s no kickstand so you might lean it against a wall but if you lay it down you’ll have to do so on the drivetrain side because of the key hole position, the second step is a slide lever to disconnect the pack and if the bike is upright the pack might sort of plunk out and get dropped more easily so be careful
  • I like that the grips are ergonomic but not super fat because you can still bear down and maneuver easily with them but wish they were locking, as-is they may twist under pressure and prolonged riding

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