Update: While we originally featured Mongoose brand bicycles in this post for their low price and wide availability, their lawyers responded indicating that their bicycles are not tested for the added load of a motor and batteries and should not be used for e-bike conversions. We have replaced these bicycles with good alternative options, but which are slightly more expensive.
Update 2: We did it – here’s our $700 DIY Fat Tire Ebike
Electric bicycles are great for recreation, allowing you to take in the sights and explore trails without working up a sweat. If you want to ratchet up the fun even more though, you’ll definitely want to try a fat tire electric bicycle. With their exaggeratedly wide tires, these bikes open the door to a wider ranger of terrain and an even more comfortable ride. From beaches to muddy trails and even snow, fat tire electric bicycles can conquer nearly any type of riding.
While there are a number of commercially available electric fat tire bikes to choose from, you can actually save money by building your own. By going the do-it-yourself route, you can also choose the exact components that are right for you. Let’s take a look at a few different ways you can build your own custom fat tire electric bicycle.
What do you need to build an electric fat tire bicycle?
The first thing you’ll need is a basic level of handiness. You don’t have to be a mechanic, but as long as you’re comfortable turning a wrench and have the necessary skills to swap a flat tire on a bicycle, then you’re probably ready to build your own e-bike.
Next, you’ll need three basic components:
- Fat tire bicycle (the donor bike)
- Fat tire electric bicycle conversion kit (includes everything except the battery)
- Battery
These are the three pieces to the puzzle, and they allow you to customize your fat tire e-bike to fit your own specific needs. Each of these components are available with different quality levels as well, which will effect the build quality, cost and safety of your e-bike.
The most common question I hear about DIY electric bicycles is “What’s the cheapest I can spend on an e-bike conversion for?”
I always shudder a little bit when I hear this, because “cheapest” and “good” rarely go together. However, I like to give people a range of options, which is exactly what I’ll do here. I’m going to layout three options, or recipes, for building an electric fat tire bike. These bikes will be something of a “good, better, best” situation, starting with the cheapest option and then adding higher quality, better features and additional cost.
Option 1: The cheapest
Here we’ll look at the absolute, rock bottom, dirt cheapest way to build your own electric fat tire bicycle. This will absolutely provide you with a fun fat tire e-bike, but the main sacrifice here is the quality of the donor bike. It has no fancy features like gears, suspension or even handbrakes. Want to stop? Channel your inner 10 year old on a BMX bike and simply pedal backwards.
For that reason, I recommend this option for use only off-road or maybe in bike lanes. But due to the lack of hand brakes, I wouldn’t ride this on the road with cars. This option is mostly for fun on open ground.
Ok, now that we’ve got that out of the way, let’s see the parts.
The fat tire bike
We’ll start with this beauty, a Krusher Men’s Dynacraft 26″ fat tire bike ($258.99). Nothing fancy, just a bike with giant tires. It will work fine for our purposes, though people usually complain about the uncomfortable seat. You might want to toss a cheap gel seat cover over it.
The electric bicycle conversion kit
For this bike, we can use either a front or rear wheel motor. Front motors are often a bit cheaper, so we’ll go with one of those on this budget build.
We’ll can select a 1 kW front wheel fat tire electric bicycle conversion kit ($209.90). This kit should get you up to ~27 mph (43 km/h). The speed and power of this kit will definitely be fun on a fat tire bike, but both are usually not street-legal in most states, so remember that this is an off-road e-bike.
Also, note that this is a lot of power to put in that front bicycle fork. Since the fork is steel and not aluminum or magnesium, it will probably be alright, but just to be safe, it’s not a bad idea to add a torque arm to help secure the motor from spinning in the fork.
The battery
The last component we’ll need is a battery. Since our e-bike conversion kit is designed for 48V, we also need a 48V battery. This 48V 15Ah battery by Vpower ($179 + $79 shipping to US) should do the trick. It’s not the highest quality battery I’ve ever seen, but it will drive our e-bike and the price can’t be beat, which is the goal of this particular e-bike recipe. We’ll look at higher quality batteries for the next couple builds.
Putting it all together
The actual conversion process is surprisingly simple. Start by flipping the bike upside-down and removing the front wheel. Pull the tire off the wheel after letting the air out of the inner tube, then transfer the inner tube and tire over to the motor wheel. Pump the tire up and then place the motor wheel back into the bike, tightening down the axle nuts and adding your torque arm if you so choose.
Bolt, zip tie or otherwise connect the controller box to the bike frame, and bolt the throttle onto the handlebars after removing the handle bar grip on the right side.
Connect the wires from the motor and the throttle to the controller. You can also install the brake levers if you’d like, but remember all they do is cut the power to the motor, since we don’t have actual hand brakes on this bike.
It is possible to add regenerative braking to the front of the bike using the motor, but you’d have to swap out the controller in your kit to a new one with a regenerative braking function. Doing so might mean that the connectors won’t match exactly, which would require some custom wiring on your part to make the connectors fit each other.
Lastly, mount the battery onto the bike, either in a bag, on the rear rack, or in a custom mounting box that you can build yourself. Then connect the battery’s positive and negative wires to the controller’s positive and negative wires.
Now you can flip the ON switch for the battery and give the throttle a slight twist while lifting the front wheel up in the air, where it should spin gloriously. If it isn’t spinning, just check your wires and make sure everything is connected to the matching connector.
You’ll probably want to zip tie the wires down to the frame, or you can even get fancy and add spiral wire wrap for a more professional appearance.
The total cost of this barebones build is $726.89, which is ridiculously little for a 27 mph fat tire e-bike. If you want to step it up a notch though, we can do a bit better with a slight bump up in quality of the components. Let’s look at that option next.
Option 2: The middle of the road
For just a little more money, we can build a fat tire e-bike that I’d be much more comfortable on. The first thing to upgrade is the bike itself.
The fat tire bike
For this middle of the road option, we’ll upgrade to the Polaris Wooly Bully fat tire bike ($279), which gives us front and rear disc brakes as well as 7 gears to choose from. Those gears will come in handy if the battery dies and we want a prayer of pedaling this behemoth back home.
The electric bicycle conversion kit
Now that we have real brakes, we aren’t stuck with a front wheel conversion kit. Let’s go with a similar style 1 kW fat tire e-bike conversion kit, but with a rear wheel motor ($208.99 + $23 shipping in US). The rear wheel motor will perform better, giving us improved traction and handling.
The battery
We have some room to upgrade here as well, which is good, because the battery is probably the single most important part of an electric bicycle. For this build, we’ll use a “Dolphin style” frame mounted 48V 11.6Ah battery ($429.99). Even though the capacity is a little lower on this battery than our previous budget battery, the cells are higher quality Panasonic cells and should last longer while providing more power. Plus this style of battery case easily mounts and locks to our bike, saving us from having to MacGyver a custom solution.
Putting it all together
The conversion process is essentially the same as in the previous budget bike above. You’ll remove your old rear wheel, swap the tire and inner tube over to the hub motor wheel, then reinstall the hub motor wheel. You will also need to transfer your gears from the old wheel over to the motor though. This can be done with a freewheel removal tool, or if you want to get creative, with common hand tools (not the recommended method).
Next mount your controller and throttle, followed by your battery. The battery will bolt onto the frame where the water bottle holder normally sits.
Lastly plug in all of your connections and you’re ready to ride!
The total cost of this build is $940.98, and results in a fat tire e-bike that I would be more confident riding due to the addition of handbrakes and a higher quality battery.
Option 3: The nicest option
I’m still trying to keep these e-bikes affordable, so this isn’t the absolute nicest possible fat tire e-bike, but its the nicest of the three options here. We could keep increasing quality and features all day, but at a certain point it just isn’t worth the cost anymore. This e-bike is about the most I’d pay to get good quality results on a budget.
The fat tire bike
For our nicest fat tire electric bike option, we’ll upgrade to a nice GMC 26″ fat tire electric bicycle ($401.84).
The electric bicycle conversion kit
Instead of using a hub-motor kit for this e-bike, we’ll use a mid-drive motor instead. This will give us both a lower center of gravity and the ability to use all of our gears with electric power, which is great for hill climbing or riding slower through sand and snow. I’d recommend either a 750 W Bafang BBS02 ($749) or a 1,000 W Bafang BBSHD ($679).
The battery
For this e-bike, I want to go with a very high quality electric bicycle battery, so I’ll choose a 50V 17.1Ah triangle battery from EM3EV ($566.70 with shipping to US). This battery is one of the best constructed e-bike batteries I’ve ever seen, and even comes with a triangle mounting bag – the same bag I use to hold the battery on my personal e-bike.
Putting it all together
The conversion process when using a mid-drive motor is a bit more complicated. It’s much easier to see it performed than to explain it, so I recommend watching the install videos. Essentially, you need to remove the pedals, pedal cranks and bottom bracket assembly from the bottom of the bike and replace it with the motor and the pedal cranks that come with the motor.
Then you’ll add the triangle frame bag and insert the battery. Finally, you simply connect all the wires to the throttle, motor and internal controller. Now you’re ready to ride!
This would be a really awesome e-bike for tough off-road conditions or city commuting, where you could hop curbs and barely feel it under the 4″ tires. The total cost for this conversion comes in at between $1,647.54 and $1,717.54, depending on which mid-drive motor you choose.
Retail alternatives
Even though I’m a big fan of the DIY method, there are still a lot of great retail fat tire electric bicycles out there. So if you want to get riding right away, you might consider skipping the part where you get your hands dirty and instead jump straight to the unboxing.
There are some decent yet cheap fat tire e-bikes, such as the GoPlus 26″ fat tire e-bike ($729.99) or the Ecotric 20″ folding fat tire e-bike ($790). The folding option is nice for those that don’t live right next to their desired fat tire bike playground and need to put the bike in their car, but the smaller wheels can make the ride a bit harsher. These are also both 36V 350 W e-bikes, so don’t expect the speed or acceleration to be overwhelming.
You could bump up the power slightly to Ecotric’s 500W 26″ fat tire e-bike ($980) for a little more excitement, but you’ll still have a 36V battery which limits the top speed and acceleration.
For real power and fun, you’ll want to look for a 48V option, such as Cyrusher’s 48V 500W 26″ fat tire e-bike ($1,639) or just throw caution to the wind with their upgraded 48V 1,000W ($2,139) version instead.
Have you ever ridden a fat tire electric bike? Let us know what you thought in the comments below!
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