How to Build an Inexpensive Electric Bicycle at Home

1 Step 1: Design and Options   

Before starting the project, let’s decide on what kind of bike we want to have. Before converting a regular bicycle into an electric one, you need a bike. The two main options are mountain bikes and road bikes. Think of the terrain you will be riding on and how much pedaling you want to do. In general, mountain bikes are usually safer and more stable due to their wide wheels and heavy frames. Road bikes generally don’t have a suspension system, which means you’ll feel every little bump. This can make you feel uncomfortable and even dangerous as you get up to faster speeds.   

Buy, Modify, or Build?  

For those trying to save money, re-building the old mountain bike might be the best bet. For new bikes, if you are lucky to get something that perfectly fits you, it may make sense to buy a stock bicycle and swap out any components you want to upgrade. Finally, if you’re a DIY enthusiast, you can always purchase all parts and build up a bike from scratch.   

Motor – Hub motor or mid-drive?   

Depending on the power and size of your motor, it’s essential to make sure that your dream bike can handle the extra stress and weight of your conversion.  

Hub Motor   

A hub motor usually replaces either the front or rear wheel hub or sometimes both wheel hubs. They are generally the cheapest option, most discrete, but low-powered.    

Mid-Drive Motor   

Mid-drive motors go straight in the middle of the bike. They usually have an extra chain that drives the front crankset, which then moves the rear wheel. One of the best advantages of mid-drive motors is that they let you shift through your rear gears as you could on a regular pedal bike, which, in turn, gives you a good range of speed and torque.   

2 Step 2: Bike Tools   

The number and variety of tools depend directly on how much you will build a bike up from parts. Unfortunately, bike tools are pretty specialized, so in most cases, you can’t just manage the project with the tools you already have.    

If bikes aren’t your lifelong passion, you’d better get an inexpensive set of bike tools that cover most of your needs.   

On the other hand, if you are not tight on budget and eager to buy all the parts separately to assemble your bike, having a complete set of tools may become a reasonable decision.   

If you’ve decided to buy a standard bike and upgrade it to an e-bike, you can probably skip the info concerning tools. In this case, your following steps will include upgrading the fork, brake calipers, brake rotors, wheels, and tires.    

3 Step 3: Electronic Equipment

Of course, you’ll need a couple of essential electronic parts for the build. They usually include a motor, a battery, a motor controller, and a throttle.   

You can certainly add some extra electronic parts, but indeed that’s all you need.  

Motor   

The size and type of motor will determine how fast you will go and how quickly your acceleration will be. Big models are heavier, consume more power, are faster to wear on chains, and more dangerous to the rider.   

Battery  

The most commonly used batteries on E-bikes are Lithium-Ion. Besides, most E-bikes get a pack of 18650 cells wired together to make one big effective battery.    

When choosing a battery pack, consider a voltage and capacity rating. The higher the voltage of the battery is, the faster the motor responds. Capacity indicator means how much energy the battery stores. High-capacity batteries can power the bike for a long time before recharging. On the other hand, higher voltage and larger capacity batteries are massive and weighty.  

Motor controller   

A motor controller is the connecting link of all of the parts. It controls power and signals to make your motor function flawlessly. Some controllers are customizable, so there are some options you can manage.   

Throttle   

The throttle controls the motor while riding. There are two types of throttles: twist throttles (mainly used on motorcycles) and thumb throttles (which you press with your thumb). By and large, it’s a matter of preference, although thumb throttles are generally considered safer.   

4 Step 4: Assembling    

Tubeless Tires   

Tubeless tires represent just what you hear: they have tough outer rubber similar to regular tubed tires, but the external tire is airtight. Besides, tubeless tires require a specific sealant to fill any tiny holes where air might escape.   

Below there are some advantages that can convince you to opt for tubeless tires over regular ones:  

• The sealant inside lets the tires be invulnerable: if you ride over a piece of glass, for instance, the substance will quickly fill up the gap, preventing your tire from going flat.   
• Tubeless tires are irresistible to cases when the inner tube gets pinched between the tire and rim, making a long gash in it and making your tire rapidly deflate.   
• You can use tubeless tires at lower pressures. The low pressure lets the tire flatten out more on the surface, adding more traction.  

Fork  

The component that goes up through the frame is called the fork. There are several types of fork tubes, so make sure you purchase the one compatible with your frame. There are many tools for installing forks, but the most efficient would be a flat head screwdriver, a soft rubber mallet, and some patience.   

Wheels to Frame   

When the tires are put on the wheels, attaching the wheels to the frame seems quite simple. If you don’t have a specific bike stand, just turn the bike upside down, so it’s sitting on the saddle and handlebars.   

The front-wheel sits in between the stanchions on the fork. Insert a quick-release axle, and this is it! The rear wheel can be mounted before or after the chain.    

Brakes and Derailleurs   

If you’ve decided to get new brake calipers, then the Avid BB7 calipers would be the best option. They’re high-quality and relatively easy to install because you can adjust them in both directions (inside and outside the rotor).   

Chains   

This stage requires a thorough exploration; however, it can be of great help.   

After the motor and front crankset is installed, it’s time to mount the chains. Here you may find a chain breaker tool helpful. Get each chain to the proper length to have a bit of slack in the most stretched but not tensioned position. The longer chain that goes back to the rear wheel should be kept tensioned by the rear derailleur. The shorter chain that comes from the motor gets additional tension due to the help of a small idler gear with a spring.

5 Step 5: Connecting Wires  

At first sight, it might look a bit confusing. Please don’t panic, actually there is nothing complicated about it. Let’s take a closer look at it:   

• Almost all the wires coming out of the controller are labeled.    
• Some of the connectors are not going to be used, at least now. Automatic pedal assist, manual cruise control, brake sensors, etc., are pretty insignificant things that you can pay attention to a bit later (or not).    
• Most of the connectors are unique. You can try to connect things that are not compatible, but the connectors won’t fit.   

6 Step 6: Safety   

The finished project should result in getting a high-powered, low-weight electric bicycle. But, unfortunately, it can often be dangerous to the riders themselves and passers-by. So here are some things that are vital to take into account:   

• Wear a helmet.    
• Upgrade to larger (180mm) disc brakes. Larger diameter disc brakes give more stopping power so that you can slow down faster.    
• Install lights.    
• Install E-brake sensors. This step prevents the case when you’re accidentally applying throttle and brakes at the same time, intending to stop, but the motor keeps moving you forward.   
• Give up a twist throttle in favor of a thumb one. Twist throttles can be unreliable. If the bike gets out of control, your first reaction is usually to hold onto the handlebars tight, pulling on the throttle more. This small mistake can turn into a severe crash. You can avoid this with a thumb throttle simply because of its location.   
• If possible, try to use acceleration ramping on your motor controller. With a large, high-torque motor, it’s easy for the bike to get out of your control if it accelerates suddenly.   

7 Conclusion  

So there you have it – a customized, designer bike that perfectly fits you and your riding habits.    

There can be dozens of different outcomes of various e-bikes that can come from the tips and suggestions above, and it is down to your imagination as to what you could end up with. So you can always try again.

To learn more about the basics of assembling a custom bike yourself, check out our next article.