2017 BULLS SIX50 E 1.5 Review


Technical Specs & Ratings



SIX50 E 1.5


Class 1


Front Suspension



Hydraulic Disc



482.4 Wh

482.4 Wh

50.5 lbs / 22.93 kgs


Tapered 1-1/8" to 1-1/2"

STYX Alloy, 7° Rise, 31.8 mm Bore, Lengths: (70 mm, 80 mm, 90 mm)

STYX Alloy Low Rise, 740 mm Width, 25 mm Rise, 9° Bend, 31.8 mm Bore

Velo Rubber Ergonomic, Locking

STYX Aluminum Alloy


Selle Royale, Active

Wellgo Alloy Platform, Cage Style

Hydraulic Disc

Tektro HD-M285 Hydraulic Disc with 180 mm Rotors, Tektro Levers with Adjustable Reach


Video Reviews

Written Reviews

Bulls created something special with their SIX50 E 1.5. This is an affordable, trail capable, city capable, electric bike offered in four sizes, running top-of-the-line Bosch drive systems. For just over $3k you’re getting a bike that looks good, is sold through a wide network of dealers globally (in the US since late 2015), and should last for years. Compared with other similarly priced models like the IZIP E3 Peak+, this e-ebike offers bottle cage bosses and fender bosses but has a higher stand-over height. Both bikes have thru-axles with quick release for easy trail maintenance or transport… but the SIX50 E 1.5 comes with a 25% larger Bosch Powerpack 500. The styling on this bike is good with an angled downtube that compliments the bulge of the battery pack and blends smoothly into the the motor casing. Note the Aluminum alloy skid plate mounted beneath the motor for protection. I was really impressed with the 50.5 lb weight of the medium size frame I tested for the video review above. That’s a good weight considering this has a coil fork vs. air, is running the larger battery pack size, and has plus sized tires with Boost (elongated) front hub spacing and unique 141mm rear hub spacing.. As someone who loves commuting through urban environments on mountain bike frames (because of the comfortable tires and shock absorbers), I could see this ebike working great as a daily ride and weekend toy. And it would definitely handle both environments, this is more of a mountain bike that was specced slightly down to mid-level vs. a cheap urban bike that looks like it could handle trails. To set it up right, I’d grab a disc brake compatible rear rack, lightweight bottle cage, and possibly some small mud guards.

Driving the bike is a Bosch Performance Line CX mid-motor. This thing is rated at 250 watts nominal but tops out above 500 watts and is capable of a peak 73 Newton meters of torque. It’s compact, super fast, and one of the smartest motors around. The motor controller measures rear wheel speed, pedal cadence, and pedal torque one thousand times per second, and it even listens for shifting to reduce drivetrain wear. It’s the same motor used on ultra high-end full suspension mountain bikes and I hear from shops and customers that it is one of the most reliable. Admittedly, I’m a Bosch fanboy because they were one of the first systems to arrive in the US that delivered the kind of power and efficiency I was craving for true mountain biking. It might actually be a little overkill on this bike, if you use it mostly for city commuting and light smooth trails, but it’s good to know that it’s so capable. Note that the motor does produce a bit of whirring noise at high RPM but that it is capable of up to 120 RPM while some other systems peak out around 100. This allows it to assist you up to the maximum speed of 20 mph in a wider range of gears, not just the highest gear. The chainring chosen for the Bulls SIX50 E 1.5 has 15 teeth vs. 18 on the comparable IZIP mentioned earlier but they both use a 10-speed Shimano Deore drivetrain. What this means is that the Bulls is going to be a more capable climber and fit the 20 mph range better. The chainring on Bosch powered e-bikes spins at 2.5 revolutions per crank arm revolution so you can multiply the teeth to get a comparable traditional chainring size (38 tooth in this case). There’s a small metal chainring guard to keep pants and other debris clear and this might also act as a guide to keep the chain from coming all the way off if it bounces free.

Powering the bike is a high capacity Bosch Powerpack 500 with 36 volts and 13.4 amp hours of capacity. It’s impressive to see this pack on a bike that is priced so low because you get 25% more capacity in the same form factor as the older Powerpack 400 and the energy dense cells used for it are in high demand. The battery mounts from the top down and can be charged on or off the frame. Make sure it’s clicked securely in place before riding because sometimes the mounts are a bit tight when they are brand new. There’s a handle at the top for easier carrying and an LED power indicator on the left side. If you’ve got the battery stored separately from the bike, to reduce exposure to extreme temperatures or just for safe keeping, I recommend topping it off every couple of months if you haven’t used it. The battery can be stored comfortably at about half-full (which is how it ships) and should be very easy to find and replace for years to come because it’s so standardized… but you may not be able to find the same sticker pattern so consider keeping that if your old pack wears completely out. Expect upwards of 1,000 full charge cycles and years of use from this pack. The charger that ships with the SIX50 E 1.5 is a faster 4 Amp model that manages to stay fairly compact and lightweight at roughly 1.7 lbs. You can buy additional chargers (including a smaller 2 Amp version) from your dealer and this could be useful to store at the office if you’re commuting.

To power up the bike, just charge and mount the battery, then press the power button near the lower left corner of the display. The screen flashes to life very quickly showing your speed, battery level, and assist level in monochrome. It’s backlit with a faint blue that isn’t super distracting but also isn’t controllable. You can have lights wired into the system by some shops and this is handy because the display has a lights on/off button and integrated lights are just easier to work with than click-on independent models, in my opinion. Again, this is most relevant to people who might want to use the bike as a commuting platform. Look for Supernova lights that are made with sturdy alloy housings that can withstand trail use. A good example of these lights in action is the Riese & Müller Delite electric bike. Anyway, the display panel is easy to interact with by using the i button either on the Intuvia LCD or the remote button pad mounted near the left grip. I love how close the buttons are and how the center i button is rubberized while the up and down arrows on this remote pad are smooth and clicky. They become second nature very quickly and that’s key if you’re riding in traffic or a dynamic trail and don’t want to look down. And with the Bosch CX motor system, you can have the firmware updated to change Sport mode to eMTB mode which acts more like a torque sensor with the full range of power. Basically, it gives you all four levels in one mode, perfect for those conditions where you don’t want to be distracted looking down or clicking around. The display is a real highlight on this and other Bosch powered electric bicycles for me. I like how large it is, that you can swivel it to reduce glare, and that it’s removable and replaceable or even swappable with the COBI smart system that uses your phone as a display panel and includes integrated lights with turn signals. The COBI system is sold separately but was designed to just click into the Intuvia mount.

There’s so much to say about this electric bike because it’s so versatile. Maybe $3k doesn’t sound affordable to you, but just one year ago it was difficult to find any Bosch powered electric bike for under $4k in the US, and it wouldn’t have had the high-capacity 500 watt-hour battery or the high-performance CX motor. Bulls offers a wide range of models and I feel that some look nicer or have great features like full suspension or the clean integrated Brose battery vs. the stuck-on Bosch Powerpack, but they all cost a lot more. This is the kind of e-bike that you could buy and keep, ride around and bang up, expect to last for many years, and really use. The top tube is a bit higher with that traditional diamond layout and the resulting higher seat tube might make adding a seat post suspension uncomfortable if you’ve got a shorter inseam length compared to the IZIP E3 Peak Plus I keep referencing. Both models are interesting to me because of what they offer and the wide audience that could enjoy it. You do get suspension lockout here and a strong pair of 180 mm hydraulic disc brakes. The Schwalbe Smart Sam tires have active line puncture protection to reduce flats and the PSI range is a bit higher than the IZIP which combines with the slightly narrower tires for a more efficient ride. Big thanks to Bulls for partnering with me on this post and inviting me out to their headquarters in Southern California to do some back-to-back tests and reviews. I’m glad that they and other European companies are entering the US and delivering some high quality products.


  • I love that even though this ebike is trail worthy, it has rear rack, fender, and bottle cage bosses! It’s a perfect platform for weekend mountain biking and weekly commuting around the city all rolled up into one
  • I think Bulls had the urban/trail commuting use-case in mind when they specced the ergonomic grips and low-rise handlebar, they hand position feels great and the grips reduce tingling in your hands for longer or more repetitive rides
  • At $3,099 this is one of the most affordable BULLS electric bikes and preserves the styling, warranty, wide dealer network, and quality that the company is known for
  • You get four frame sizes to choose from! That’s incredible at this price, and it’s important given the diamond frame (high-step) because the top tube is fairly high
  • A 120 mm spring suspension and plus sized tires offer comfort and traction, I’d consider adding a 30.9 mm seat post suspension like the Thudbuster ST for an even smoother ride
  • Stiff thru-axles on both wheels with longer Boost thru-axle up front, this provides stronger bracing angle for the spokes and accommodates the plus sized tires
  • Considering this ebike is using a spring suspension, I’m very impressed with the 50.5 lb weight, spring suspensions require less maintenance and tend to be very responsive
  • Diamond frames tend to be stiff and strong without additional metal (and weight), I like that you can lift them easily and carry them on hang-style racks
  • Beautifully integrated mid-motor and battery pack, notice how the frame tubing cups the base of the battery and helps it blend into the frame
  • The Bosch CX motor offers high torque and can be updated to eMTB mode which changes Sport into a wide range “do everything” setting that works more like a pure torque sensor, it’s perfect for off-road when you don’t want to fiddle with power level
  • Solid mid-level Shimano Deore drivetrain with 10 speeds to work with, this is enough for climbing and exceeding the top electric-assisted 20 mph speed
  • Responsive hydraulic disc brakes with large 180 mm rotors and adjustable reach levers, great for trail riding and the levers are nice if you get the smaller frame and have smaller hands or ride with thick gloves
  • I love that you get the latest Bosch Powerpack 500 with this bike, especially considering the price point, this pack offers 25% higher capacity than the standard Bosch Powerpack 400 but is backward compatible with that pack if you happen to already own one
  • The motor controller measures pedal cadence, pedal torque, and rear wheel speed 1,000x per second and feels very natural, it also listens for when you shift gears and tries to ease off power to reduce wear on the chain, sprockets, and derailleur
  • The motor is angled up and built into the downtube and seat tube area of the bike, this raises clearance, Bulls chose minimal casing to keep the bike looking sleek but did add an alloy skid plate along the bottom for protection against rocks and other obstacles
  • I love how the battery pack and display can be easily removed for safe storage or charging, this is a big deal if you commute with the bike and have to park outside at a public rack
  • The Bosch Intuvia display panel has a Micro USB port built in that sends 5 Volts at 500 milliamps so you could maintain a phone or charge other portable electronics while riding, this is great if you use your phone for GPS
  • This and most other Bosch powered electric bikes have walk mode which allows the bike to push itself forward slowly, this is especially useful if you have a rack loaded with gear in the city or are pushing up a steep hill in the mountains (like a technical section that you decided to walk)


  • While the Bosch Performance Line motors are super responsive, they do produce a bit of hum or whining noise when used in the highest levels of assist or operating at high RPM
  • Many of the Bosch powered electric bikes stand out as being electric because the battery is connected to the frame vs. being slotted inside of it, but this makes removing and charging the pack easier and the standardized configuration makes it easier to replace
  • Plus sized tires tend to be a little heavier but the 2.6 is a good compromise (lighter than 2.8 or 3.0), you could always run them tubeless, still, they will add some drag and produce some buzzing noise on pavement
  • If you do plan to use this as a commuting platform, make sure you lock both wheels and the saddle because the quick release systems make them easier to steal
  • Sometimes when the Bosch battery packs are new, they require additional effort to click into place, just make sure it’s secure before riding off to avoid damage, shops can loosen or tighten the interface which is designed to reduce rattling
  • The pedals are a bit basic, I would consider replacing them with something with a wider platform and adjustable pins if you plan to ride trails or all-mountain, these Magnesium Wellgo pedals are a good option
  • The alloy bash guard on the chainring seems like it’s spaced out pretty far from the actual chainring, I haven’t noticed chain drops being an issue with Bosch? Perhaps this extra clearance reduces chain suck in muddy conditions?

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