Building Your Own Fat Tire Electric Bike: A Step-By-Step Guide

Fat tire electric bikes are a fun and exciting way to explore the outdoors while getting some exercise. They are also known as plus bikes and are designed for all-terrain riding. They are equipped with a powerful electric motor that provides pedal-assisted or fully electric riding modes, making it easier to conquer hills and rough terrain. Building your own fat tire electric bike can be a fun project and can save you money. It is important to have a basic level of handiness and ensure that you have the right tools and instructions before you begin. You can build a fun fat tire e-bike for as little as $700, but the quality of the donor bike will be a factor in the overall performance.

Characteristics and Values of a Fat Tire Electric Bike

Choosing the right bicycle frame

When building a fat-tire electric bike, choosing the right bicycle frame is crucial. The frame geometry, size, and material all play a significant role in the performance, comfort, and handling of your bike. Here are some essential factors to consider when selecting the right bicycle frame:

Frame Geometry

The frame geometry of an electric bike refers to the relationship between the handlebars, saddle, seat height, and the length of the frame tubes. It also includes the resulting angles of the bicycle frame, handlebar settings, and saddle position. A narrower head tube angle provides more stability, especially during descents and cornering, while a wider angle offers more direct steering and easier position shifts when climbing. Additionally, a longer front centre, which is the distance between the centre of the bottom bracket and the front hub, improves stability over bumps and on steep climbs.

Frame Size

To choose the appropriate frame size, consider your height and leg length. Many manufacturers provide size charts based on the rider's height. A good rule of thumb is to look for a frame that allows you to easily straddle the top bar with at least an inch of clearance. If you're primarily riding on trails, a mountain bike-style frame with a more upright position is ideal. For road riding or racing, opt for a frame that positions you in a more forward-leaning posture for improved aerodynamics and comfort.

Frame Material

The most common materials for electric bike frames are aluminium, steel, and carbon fibre. Aluminium is popular due to its lightweight, affordable, and durable nature. Steel frames are known for their strength and stiffness, making them ideal for heavier riders or off-road use, despite being heavier. Carbon fibre is the lightest and stiffest option, providing high-performance rides, but it is more expensive and requires careful handling.

Remember, when in doubt, consult a professional or a qualified technician. They can provide advice based on your specific needs, such as your riding style, terrain, height, and weight, to help you choose the most suitable frame for your fat-tire electric bike project.

Selecting a conversion kit

If you're looking for the most affordable option, a front-wheel fat tire electric bicycle conversion kit is a good choice. These kits typically cost around $209.90 and offer a fun riding experience with speeds of up to ~27 mph (43 km/h). However, it's important to note that this setup may not be street-legal in most states due to its high power, and it's recommended to add a torque arm for safety.

For a slightly higher budget, you can opt for an upgraded bike with front and rear disc brakes and gears. This option provides more comfort and convenience, especially if the battery dies and you need to pedal. With this upgrade, you can choose a rear wheel conversion kit, which offers improved traction and handling. The rear wheel motor kit typically costs around $208.99 plus $23 for shipping in the US.

When selecting a conversion kit, it's essential to consider the quality of the donor bike. Cheaper options may not include features like gears, suspension, or handbrakes, so it's important to strike a balance between cost and performance.

Additionally, pay close attention to the battery specifications. Ensure that the voltage of your chosen conversion kit matches the voltage of the battery you intend to use. A long-lasting battery is crucial, as it is often considered the most important part of an electric bicycle. Look for a battery that can take you at least 50 miles on a single charge.

Finally, consider the motor power when selecting your conversion kit. A more powerful motor will provide better performance, especially when tackling hills and rough terrain. Aim for a motor with at least 500 watts or more to ensure a smooth and enjoyable riding experience.

Remember, building your own fat-tire electric bike gives you the freedom to choose components that suit your specific needs and budget. Take the time to research and compare different conversion kits to find the perfect match for your dream electric bike.

Installing the seat

Firstly, ensure you have the correct seat for your bike. The seat, also known as the saddle, is typically included in the box with the other components when you purchase a bike for self-assembly. Once you have the seat, you can begin the installation process.

The next step is to insert the seat post into the bike frame. The seat post is the long, thin part of the seat that will be attached to the bike. It's important to adjust the height of the seat post to match your leg length and riding style. If you plan to ride with a more upright posture, you may prefer the seat to be higher. For a more aggressive, aerodynamic position, you might lower the seat.

After adjusting the height, tighten the seat clamp to secure the seat post in place. The clamp is usually located at the bottom of the seat post and can be tightened with an Allen key or a wrench. Make sure the clamp is tight enough to hold the seat post firmly in place, but be careful not to over-tighten it, as this could damage the clamp or the frame.

Now that the seat is attached, you can fine-tune the height adjustment. Sit on the seat and check that your legs can comfortably reach the pedals. You may need to adjust the seat height slightly to ensure an optimal riding position. Once you're happy with the height, tighten the clamp again to ensure the seat is securely locked in place and won't slip during your rides.

Finally, test the seat by gently sitting on it and trying out the bike. Make sure the seat feels sturdy and doesn't wobble or move when you pedal. If everything feels secure and comfortable, you've successfully installed your fat-tire electric bike seat!

Attaching the battery

Firstly, ensure you have selected a suitable battery for your bike. Consider the voltage requirements of your electric system; for instance, if you have a 48V e-bike conversion kit, you will need a 48V battery. Additionally, think about the range and battery capacity you desire. Aim for a long-lasting battery that can take you at least 50 miles on a single charge.

Now, let's get into the installation process. If you're working with a pre-built commercial fat-tire electric bike, refer to the instructions provided by the manufacturer. They will guide you through the specific steps for attaching the battery to your bike model. Follow the instructions carefully to ensure a correct and safe installation.

For those building their fat-tire electric bike from scratch or using a conversion kit, you'll need to determine the optimal location for the battery. Consider the weight distribution and ensure the battery is securely mounted. You may need to fabricate a custom mounting solution, such as a battery cage or bracket, to hold the battery in place. This could involve welding or drilling, so ensure you have the necessary tools and skills or seek assistance from someone with fabrication experience.

Once you've identified the mounting location, it's time to attach the battery. Secure the battery firmly in place, ensuring it doesn't move or vibrate during rides. Use appropriate fasteners, such as screws or bolts, to attach the battery to the mounting bracket or cage. Make sure the battery is easily accessible for maintenance and charging.

Finally, connect the battery to the electric system. Carefully route the battery cables to the motor and other electrical components, ensuring they are secured and don't interfere with the moving parts of the bike. Consult a wiring diagram specific to your bike model or conversion kit to ensure proper connections. Test the connections with a multimeter to confirm continuity and ensure there are no loose connections or shorts.

With the battery attached and connected, you're almost ready to ride! But first, test the setup by turning on the battery and powering up the bike. Check the display screen to ensure it shows your speed and assist level. Take your new fat-tire electric bike for a spin and enjoy the thrill of riding through various terrains with ease. Remember to follow local regulations and safety guidelines when riding your electric bike.

Testing and riding

Firstly, ensure that your battery is charged and ready to go. You should also check that your tires are inflated to the recommended pressure, which is 20 PSI for most fat tire electric bikes. Keep in mind that fat tire electric bikes can be heavier and bulkier than regular bikes, so it's important to practice handling them with care before hitting the trails. Practice turning in an empty parking lot or on a quiet street. Remember to keep your body upright and lean the bike underneath you when turning, and avoid making sudden turns as this can throw you off balance.

When you're ready to ride, adjust your seat height so you can comfortably reach the pedals. To start, push off with one foot while pressing the throttle or pedalling to move forward. You can use the throttle for pedal-assisted riding or fully electric riding, which is excellent for conquering hills and rough terrain. When stopping, squeeze the brake levers and come to a complete stop before getting off the bike.

Now that you've mastered the basics, you can take your fat tire electric bike off-road and explore all types of terrain. Keep your weight centered on the bike when trail riding, and use your arms and legs to absorb bumps and obstacles. When riding uphill, lean back, and when riding downhill, lean forward to maintain your balance. If you're feeling adventurous, you can even try jumping and dropping with your bike. Just remember to always put safety first and wear the necessary protective gear.

Lastly, don't forget to have fun and enjoy the thrill of riding your very own custom fat tire electric bike!

Frequently asked questions