The Haibike XDURO Fatsix arrives in America Spring 2015… just after the snow melts. The good news is, this bike delivers a couple things that are really unique in the world of fat style electric bikes; a premium mid-drive motor system for power and efficiency in sand or snow as well as a light-weight air suspension fork with remote lockout. The frame on this bike had to be custom built to accommodate the wide 4″ fat tires (Schwalbe Jumbo Jims) but despite this custom fabrication it’s going to be made available in three sizes to fit a wider range of riders! In terms of rideability, I love the step-down top tube that makes standing over the bike easier on uneven terrain.

The rear dropout (where the rear wheel mounts) has been customized so that the fatter wheel and a 10 speed cassette would fit. Having 10 gears to choose from makes the bike easier to ride on hills, flats or off-road conditions. The bottom bracket and spindle were also widened so the chain would align properly and these are not minor changes… They definitely add to the price but the aesthetic of the Fatsix remains in tact and it’s actually priced the same as one of the other Bosch powered fat bikes this including the LEBOWSKe from Felt. Note that the Fatsix is roughly five pounds heavier, but you get the suspension fork. I personally love the camouflage and fun orange accents on the Fatsix, including the tire that appears vividly through the weight saving holes in the Alex rims (pictured below). The front and rear wheels also feature thru-axles which are sturdier and stiffer than standard skewer axles, making them better at managing the high forces of large tires on rough terrain. In short, this is a premium electric fat bike that’s very capable of power and distance and isn’t just a novelty play on the fat form factor which has become popular in recent years.

Despite the larger tires which increased friction and starting-inertia, the Haibike Fatsix reaches 20 mph almost as easily as its trail oriented ebike cousins from Haibike that use more traditional sized tubes (like the RX 29″ or the FS RX 27.5″). The motor on all of these bikes offers 350 watts of power in a geared configuration that leverages the same gears that you do as a rider. That means the motor can operate more efficiently and go further on limited battery capacity. The controller on this bike measures the bicycle rolling speed, your pedaling speed and your pedaling force roughly 1,000 times per second to activate and de-activate quickly and smoothly… but when it does go, it delivers a lot of force. You get up to 60 Newton meters of torque (which is higher than the average 40 Nm on most 350 watt geared hub motors). So efficiency and power are nice but the other advantages of this mid-drive are that it keeps weight low and centered on the bicycle frame, which is important for stability when going off-road, and it also makes servicing the wheels and tires easier. This is always a “nice to have” feature on any bike but with an extra-large fat bike it becomes a lifesaver. The Fatsix will be much easier to fit into a car or pickup bed with one or both of the wheels removed because they’re just so wide. In the picture below, note the custom bottom bracket and spindle that were widened to align the chain as mentioned earlier.

The battery pack used with the XDURO Fatsix is a 36 volt 11 amp hour Lithium-ion configuration that’s light weight and durable (expect 1,000+ charge cycles if you take care of it). It’s removable for easy charging or multi-pack use on longer distance rides. Even though the official specs say 25 to 35 miles my experience is that it’s capable of going much further (depending on the terrain and level of assist). While the Fatsix isn’t as efficient as road style haibikes like the XDURO Race, it’s pretty impressive just how far it can go on a charge on flat hard terrain. As soon as you get into snow or sand however, expect the range to drop off and pay attention to the range readout so you can adjust pedal assist accordingly and make it home alright. I’ve created a video overview of the Bosch Intuvia system here that explains the range menu. The pack itself has a nice LED indicator on the side that displays its charge level even without turning the bike on (or even having it mounted to the bike) and that’s great if you’re storing the bike in the garage. The pack mounts low and center, just like the motor, but does take up the space where a bottle cage might have otherwise been mounted. That’s one of the drawbacks to this electric bike and note that there aren’t bosses on the rear seat stays where you might mount a rack or fenders either.

The display unit on the Haibike Fat six is large and easy to use. The screen is backlit and shows speed, distance and assist and you can interact with it using a stand-alone button console. This means you can keep your hands on the grips at all times (critical for trail riding on bumpy or dangerous terrain). The button pad is pretty easy to use, even with gloves on, and only has three buttons which are sort of oversized and tactile so you can hear or feel them click with each press. The assist-only operation of this and other Bosch powered electric bikes eliminates the chance of accidental acceleration based on squeezing the grips harder (for stability or in a tense moment) and the centerdrive is so responsive as mentioned earlier, just note that this bike doesn’t have a throttle… you must always pedal to make it go. Back to the display panel, it can be taken off of the frame easily for storage just like the main battery and the button pad has a little USB outlet for charging devices (though I’m not sure the voltage is high enough for iPhones). The LCD screen and accompanying system are water resistant and modular so if something does break you can get replacement support and keep on riding, it’s also backlit and there are some shops out there who will wire in lights to run off of the main battery and operate through the display pad. Very cool stuff.

The Fatsix is a fun bike to operate and show off… It’s a bike that makes people smile but really is rugged and capable. With tough locking grips, nice oversized disc brakes, a solid warranty and lots of shops who will be carrying it I expect it to be a hit. It’s easy to recommend any electric bike with the Bosch second generation centerdrive motor and battery system because it has proven itself on so many other ebikes I’ve tried. whether you’re a heavier person or someone who is climbing steep terrain, I believe this motor will still impress. The fact that the frame is going to be made in three sizes is just amazing to me because so many electric bikes aren’t and that can be a deal killer for some tall guys and girls. The Fatsix is a leader in its class and as someone with a sensitive back and neck, I love the suspension fork. Being able to lock and unlock remotely is awesome when transitioning from road to trail and the oversized tires already add a lot of cushion. You could always go extreme and get a suspension seat post for this thing as well! As mentioned earlier, the real drawbacks are no bottle cage or rack mounts and a higher price… and possibly not having a kickstand :)

Pros:

One of the only fat style electric bikes I’ve seen with a front suspension fork, the only Bosch powered fat bike I’ve seen with suspension

Oversized super-wide suspension is light weight because it uses air and easy to operate because it features a remote lockout button (mounted on the right bar)

Heavy duty 15 mm thru axle on the front and 12 mm thru axle on the rear for stiffness and strength in off-road conditions (also makes aligning disc brakes easier when servicing wheels)

180 mm hydraulic disc brakes front and rear, easy to actuate and incredibly responsive – perfect for managing unstable terrain and larger riders

Awesome flat paint with fun jungle camouflage colors and orange accents, the bike just looks fun

The frame is available in three sizes! This is pretty impressive for a niche fat bike and very welcome news to taller riders who might feel squished on smaller frames

Mid-step frame is easier to mount and stand over but still stiff and sturdy like a traditional straight diamond frame

Some very custom engineering to make the rear dropout wide enough for the oversized wheelset and 10 gear cassette, the bottom bracket is also custom (extended) to accommodate a longer spindle and align the chain with the rear cassette

Both the front and rear wheels offer quick release which makes servicing the bike easier and helps to reduce weight and size during transport

Premium parts all around, Shimano Deore XT drivetrain, Shimano hydraulic disc brakes, Bosch drive system, Alex rims, Schwalbe tires

Solid two year warranty, wider availability and support (managed through Currie Technologies in the US)

Pretty light for a fat bike at ~53 lbs (varying a bit by frame size), I actually weighed the bike and was impressed given the larger tires and suspension fork

Centerdrive offers very impressive torque at 60 Nm which is important for climbing or trudging through sand and snow

Bosch drive system is efficient because it leverages the gear that you’re pedaling in (and this bike has 10) so it’s powerful but also has impressive range

Cons:

No water bottle cage mounting points on the frame (may need an aftermarket adapter or CamelBak) and no rear rack mounting points, may also be difficult to fit fenders

No throttle mode here, this ebike only offers pedal assist (like all Bosch powered systems) so you have to contribute to make it go

Unique 4″ tire and tube width may be more expensive to service and replace because it’s less common (true of any fat bike)

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