- Full suspension fat bike with a high quality mid-drive motor from Bosch and their updated 500 watt hour battery pack for extended range
- Cool fluorescent paint job that extends all the way through the fork, rear shock housing, swing arm and battery pack, I think the battery blends in nicely and appreciate the metal base cup
- Premium hardware here including tubeless-ready Schwalbe Jumbo Jim tires that can be ridden at lower pressure, light weight punched out rims and RockShox air fork
- Eleven speed Shimano Deore XT drivetrain with chain tensioner, shift sensing software in the motor controller, Magura hydraulic disc brakes and thru-axles for improved stiffness
$0 (0 €)$18,000 (16,920 €)
0 lbs (0 kg)220 lbs (100 kg)
0 mph (0.0 km/hr)50 mph (80.5 km/hr)
0 watt3,000 watt
0 in (0.00 cm)22 in (55.88 cm)
0 Newton meters250 Nm
Fat tire electric bikes offer a perfect blend of technology and adventure in my opinion… an unpowered fat bike is fun, sure, but the added weight and drag of larger wheels and tires means that most people are limited in how far and long they can actually enjoy the ride. Furthermore, if you actually do seek out the snowy fields and sandy beaches that those fat tires yearn for (as I did in this video review), they can become uncomfortable because the terrain isn’t always smooth! And once you’ve added suspension there’s increased weight and often some bob as you pedal along. So that’s where this whole full suspension fat tire electric bicycle concept fits in… In many ways, it isn’t that surprising right? We see full suspension motocross bikes all the time, in fact I think most motorcycles (even road bikes) offer full suspension. But they’re loud, heavy and usually illegal on bike paths, mountain trails and beaches. The Monster E FS delivers something special in this domain, an ebike that’s both capable of handling a wide variety of terrain and usually well accepted there. It’s made with some of the best consumer/performance level hardware on the market as of this review (Magura brakes, Shimano Deore XT derailleur) and is driven by one of my favorite motor systems around, the Performance Line CX from Bosch.
With internally routed cabling, a sporty paint job and some additional metal shields in place, the battery pack truly blends in on this bike. And despite offering about 25% larger battery capacity than the previous Powerpack 400, the battery form factor is exactly the same and it weighs less than a half a pound more! You can still charge it on or off the bike and it’s even backwards compatible so if you already own a Bosch powered electric bike from the 2014-2016 timeframe you can swap them out or carry an extra along for increased range. Having tested and reviewed some of the other BULLS electric bike models recently, those with the more tightly integrated Brose battery/motor system, I gained renewed appreciation for how beautifully and simply the Bosch pack clicks in and locks. You don’t have to worry so much about bumping the key if you accidentally leave it in and you don’t have to physically twist the key to lock the pack… just when you unlock it, and this increases security. Going from there, the control panel and button pad that let you interact with the battery and motor are both very well done. You can switch assist levels on the fly without lifting your left hand and compromising your grip… just a bit of thumb work. And you can also cycle through display readouts this way. One of my favorite menus is range approximation because it dynamically updates depending on how you’re riding, what assist level you’ve selected and how much battery capacity remains in the pack. This is the sort of feedback that ensures you won’t get stuck way out in the backcountry with a depleted pack. This is especially relevant because the battery indicator only shows five bars vs. 10 on some other bike displays. That’s one of my minor gripes.
If you do get stranded on this ebike, no worries because it has a wide range of 11 gears for pedaling. And in the electric bicycle world, that’s quite a few! I found that the bike was operable on human power alone (especially on pavement) and enjoyed the rolling momentum that the tires offered once up to speed. It was easy to handle the bike on all terrain types we tested thanks to longer mountain bike style bars with locking Ergon grips and I appreciated the remote lockout on the Bluto suspension fork. Many of the hardware components chosen for this bike are of a higher build quality and designed to be light weight. At just under 56 lbs… this is what I would consider very light given how large it looks and the fact that it’s a fat bike with full suspension. It is missing a few things though, no kickstand means it could tip into your fancy car in the garage more easily and no bottle cages mean you’ll need a hydration pack. Part of me yearned for throttle on demand operation in addition to pedal assist but I recognize that this would change the class of the bike, exhaust the battery much faster and ad clutter to the cockpit. It might also delay how quickly the motor cut out resulting in sketchy performance on difficult technical terrain. Yes, this is a hard core capable bike that would handle serious riding. Bosch offers one of the most responsive, zippy feeling drive systems around and if you’re in the highest level of assist (there are four to choose from) it works very well, almost responding like a throttle without requiring exhaustive pedaling force. Almost as soon as you’ve stopped pedaling, the motor also stops and that’s a great feeling… but it works the other way too, responding especially fast as your cadence increases (ie. shifting to lower gears for climbing or maneuvering through an obstacle course of rocks, ice or fauna).
I honestly don’t have many complaints to share about this ebiket. Its great that given just how custom and unique a build it is, BULLS was able and willing to manufacture two sizes. Their two year comprehensive warranty is excellent and despite the perceived higher price point, I actually think you’re getting a good deal relative to what other companies charge for similarly specced builds using less interesting drive systems. Consider their hardtail Monster E model if you’re looking to save $1,000 and don’t mind a stiffer rear… In that case you could always add a seatpost suspension as a compromise. As someone with limited storage space, I tend to choose one high quality bike to “do it all” and that’s exactly what this offers. You get comfort, longer lasting parts and a bike that won’t quite. In a world with more and more 3″ tires it’s great to see an actual full sized 4″ wide fat tire bike that’s done so well. Powerful hydraulic disc brakes, thru axles, a tapered head tube and a custom replaceable metal skid plate make this bike extra tuff. Not to mention the chain tensioner with fully surrounding guide and narrow wide teeth. I love that you can easily and quickly take both wheels off for compact storage and transport and am glad that BULLS opted for the four bar rear suspension design to optimize traction, reduce bob and lower as much weight as possible. It’s a great bike, lots of fun and easy to use. Compared with some other full suspension fat ebikes I’ve tested, it offered a wider range of pedaling speeds while still supporting me with motor power. The motor is just more capable at high RPM and that’s how I prefer to pedal, it happens naturally as I shift down approaching hills, I don’t feel like the motor quits on me. As someone with sensitive knees, this has been one of my favorite fat bikes so far and I’m optimistic about how it could be used on so many terrain types and in so many seasons. Big thanks to Bulls for partnering with me for this review.
- Custom paint and decal job that includes the frame, rear swing arm and pivot point, suspension fork and rear suspension housing! EVERYTHING matches and looks awesome
- Sturdy 15 mm thru axle on the front with 12 mm at the rear, keeps the larger heavier wheels tight and responsive, both offer quick release which is handy for repairs or simply transporting the bike since it’s so large
- In addition to removable wheels, the battery pack and display console are also removable… I love that the battery can be charged on or off the frame and is backwards compatible with the older Bosch Powerpack 400 batteries
- Top-end components from Magura, Rock Shox, Schwalbe, Ergon and Shimano that will hold up in off-road conditions and are backed by the BULLS comprehensive two year warranty
- I was impressed that even with the larger capacity battery, full suspension setup and fat tires this bike weighs just ~55 lbs and I love that it comes in two sizes for improved rider fit
- Most of the weight is positioned low and center across the frame, this improves handling and since it’s a mid-drive, reduces unsprung weight compared to a hub motor
- You get 11 gears so pedaling feels comfortable at a wide range of speeds… even if the bike is turned off and the Bosch motor offers shift sensing to reduce wear
- I love that they included a chain tensioner with a full hood to act as a guide (clearing debris and mud), it should reduce kickback from the rear swing arm and the narrow wide tooth pattern is designed to reduce chain slip
- Punched out rims reduce weight, look cool and might add some cushion to the tires for improved comfort and traction at lower PSI
- Sturdy metal motor cover… like a louvered push guard on a truck, designed to protect the sensitive bits but be replaceable if you encounter major damage
- This is the only Bosch powered full suspension fat bike I’ve seen to date and is definitely my preference in terms of power, zip and responsiveness compared to Yamaha and other mid-drive systems, the chainring spins fast and is super quick to start and stop which is great for unstable terrain
- The Bosch Intuvia display panel is large and easy to read, simple to use and doesn’t require that you reach far while holding the grips to operate, a remote button pad with tactile feedback is mounted very close to the left grip… I also like that the display panels has a Micro USB charging port built into the side for maintaining your portable electronics
- The bike worked fine in the sand but requires pedaling (Class 1 pedal assist) and there are times when it’s nice to have throttle power just to power through soft terrain or get started again after stopping… the benefit of Class 1 is that it’s allowed on more trails vs. Class 2 throttle powered ebikes
- The rear suspension joints and shock take up the space where a bottle cage or other accessory mount might have been fit… you can’t add a rear rack easily (unless you compromise with a beam rack) so you might end up using a hydration pack all the time
- The Bosch battery doesn’t blend in with the frame quite as nicely as the Brose battery on some other BULLS ebike models but it is easier to remove and comes in a higher ~500 watt hour capacity here for longer range rides, I like that the built some metal plates around the base to help it blend in… and added those matching yellow stripe stickers
- This is an expensive electric bike… you’re getting a lot of high quality hardware but if you ride it near saltwater without rinsing it afterwards or if you’re on other corrosive terrain frequently (salted snow?!) then it will wear out more quickly, there’s a trade-off with bikes like this where you can get one that’s pretty good for half the price and then completely replace it in a year or two vs. one very nice one that you need to care more about to extend