BULLS SIX50 E FS 3 RSI Review

UPDATE: The SIX50 E FS 3 RSI is still being sold by BULLS, even though this particular review was conducted several years ago. They have since updated the Bosch motor to Gen 3 and the battery to PowerPack 500! This means improved performance, power, and range. I’m leaving the review unchanged since the videos, photos, and writeup all represent the older product that I covered :)

Full suspension mountain bikes are my favorite type of ebike because they deliver comfort and a “go anywhere” build that can work on the trails, mountainous terrain or just as well in the city. Sure, there are no fenders, no rack mounting points and no bottle cage… but I usually wear a backpack large enough to fit my laptop or some basic supplies and food. The thing about electric bikes is that they get you to your destination faster than traditional pedal power bicycles, thus encouraging more frequent and lengthy rides. The flip side of the coin is comfort, riding any bike for an hour or more can get a little uncomfortable and thus, fatter tires and full suspension takes its place. Don’t get me wrong, this is a fully capable off-road machine that would be great for dedicated trail riding or all mountain… even cross country if you stiffen up the rear shock. I love the remote lockout on the fork because it allows you to minimize bobbing on smooth terrain, really empowering you to pedal. And that’s also where the drive system shines.

Powering the BULLS SIX50 E FS 3 RSI is a Bosch drive system with upgraded high-torque CX motor. It spins super fast, is extremely responsive, packs in shift sensing and is very durable. My Uncle has been using an older version of this drive system on a full suspension bike for nearly two years now without any motor or battery issues. He added some fenders and a beam rack but often just wears a backpack. That’s the thing about this type of bike, it can be your transportation and your weekend fun! The increased drag of 2.25″ wide knobby tires and added weight of the 400 watt hour battery pack are easily overcome by the motor which should deliver upwards of 30 miles per charge… ~60 if you keep the assist level low. There’s no throttle but my experience with the system has been that the four levels of assist actually mean something with the lowest just overcoming the weight and drag of the bike and the highest feeling super responsive and powerful. You should be able to ascend nearly anything as long as you switch gears appropriately. In the video review above you can see me climbing some impressive sections off-road with constant speeds above 13 miles per hour, even reaching 17 and 18 at some points.

The drawbacks of the Bosch system is that it doesn’t blend in with the bike especially well. The bike stands out as being electric which might bother you riding off-road where others are getting around the old fashioned way. Bulls has done an excellent job integrating the motor and battery in my opinion, blending the colors and surrounding and sort of cupping the base of the battery with some extra metal flanges. I love that in addition to a chainring protector there’s a tensioner with narrow wide teeth to reduce kickback and chain slip. The tensioner is surrounded by a guide that might clear debris and also protect your clothing (if you’re commuting to work with pants for example). I like the four bar rear suspension as well, it orients the RockShox Monarch vertically keeping weight low but unfortunately also taking up the triangle space where a bottle cage might have tried to fit. The frame comes in three sizes for improved fit and since you’ve got quick release on both wheels and a super easy to remove battery and display this bike can be tossed onto most car racks or thrown into the trunk. It’s versatile, good looking and… kind of expensive. Given the Shimano hydraulic disc brakes, Deore XT 11 speed drivetrain and other upgrades like locking Ergon grips, Schwalbe tires and thru-axle design (front 15 mm and rear 12 mm) you’re opting into a higher end product. But, you get what you pay for and Bulls offers a solid two year comprehensive warranty with five on the frame. It’s an e-bike that’s built tough and fairly complete though I would love to have seen a seat post dropper. The seat tube is wide accommodating 30.9 mm posts so you could upgrade this yourself. I prefer the zippy feel and power of the Bosch system to the Brose and others, I really appreciate the shift sensing technology even if it does’t work flawlessly. The speed at which the motor starts and stops is very easy to work with and allows me to pedal more naturally at higher RPM. The motor does make a little bit of extra whining noise as demonstrated in the video but overall it’s great. Bulls did a nice job protecting it with an Aluminum scuff guard along the bottom that’s replaceable if you really push it to the limit. Big thanks to Bulls for partnering with me for this review.

Pros:

• This is my favorite type of electric bike, having adjustable suspension front and rear significantly improves ride quality as you go further and at higher average speeds… both shocks are from RockShox and are light weight air designs, the front features remote lockout for easy positioning on cross country rides where the rear might be set stiff simulating a hardtail
• The Bosch drive system is a proven winner that will last a long time and be serviced efficiently (through Magura in the US) if something goes wrong, batteries are easy to find and the system is forwards compatible with the new 500 watt hour battery pack
• The combination of wheel speed, crank speed and pedal torque measurements delivers some of the fastest pedal assist response I’ve gotten to try and I love that there’s an integrated shift sensing system to reduce chain and sprocket damage (especially for an off-road bike like this)
• The bike has a nice aesthetic, everything from the colors they chose to the motor integration and battery seat help to blend the bike with the electric systems
• Excellent power delivery thanks to the Bosch CX motor which offers higher torque output of up to 75 Newton meters in the highest assist level
• Both the battery pack and display panel can be removed from the bike easily, this is nice for transport, outdoor storage and if you’re riding on difficult terrain and are concerned about crashing the bike…
• The 27.5″ wheel size has become popular for trail, all mountain and some enduro ride styles because it carries momentum and spans gaps in terrain while remaining maneuverable and relatively light weight
• I love the enlarged rubber slap guard on the right chain stay, it should keep the entire length chip free despite the lower chain height and possibility of bounce given the off-road nature of the bike
• Awesome tires from Schwalbe, the Rocket Ron model comes tubeless ready and has evolution liteskin which means thinner lighter weight sidewalls to reduce overall bike weight
• Sturdy 15 mm thru axle on the front wheel improves strength and handling, I find that it also makes swapping wheels quicker and easier, especially with disc brakes because they line up easier, you get quick release in the front and rear for easy trail maintenance and transport
• Large bash guard surrounding and protecting the sprocket, nice chain tensioner and guide just ahead with a surround design that will not allow it to come off track and might clear debris and mud reducing chain suck
• Beautiful wire management (as with most Bosch electric bikes) the shifting and brake cables as well as electronic wires are all internally routed through the frame
• Four bar suspension with vertical shock in the rear keeps weight low, limits kickback and performs well under heavy braking but can bob a little more
• Slight rise in the handlebars and option to flip the stem for negative angle can help to protect the display in the event of a crash, I’ve seen this sort of design with some Haibike models as well
• The Intuvia display is awesome because it’s large enough to read, backlit and uses a remote button pad so you can switch between assist levels without taking your hand off the left grip, there’s an integrated Micro USB port on the right side of the display for charging portable electronics and I like the range approximation in the menus

Cons:

• Motor operation is louder than some of the other mid-drive systems I’ve tested from Bulls and Impulse in the past but response time is noticeably faster
• Compared with some in-frame battery designs, the Bosch PowerPack stands out a bit more and could generate unwanted attention… however, it’s more convenient to access and tends to be less expensive to replace
• Given the Shimano drivetrain and brakes, the premium grips, saddle, tires and suspension this bike ends up costing more… would be nice if it had a seat post dropper for the price (the diameter of the seat post is wider at 30.9 mm so at least it should fit droppers if you get one after market)
• I’m not a huge fan of the cage style platform pedals because they don’t offer as much surface area and can get bent in at the end (as seen in the video and pictures), consider replacing with clip in designs or a solid platform like these Magnesium Wellgo pedals
• No bottle cage bosses, that’s kind of to be expected given the battery replacement and full suspension design but some of the Brose powered Bulls models were able to add them due to the integrated battery design

Resources:

• Official Site: http://www.bullsebikes.com/product/six50-e-fs-3-rsi/
• More Pictures: https://goo.gl/photos/CKTLZxC4gowcdyh29