Convert a Mountain Bike into Electric: A Step-by-Step Guide

You just purchased a wicked ride but want it to be even sweeter! The process of turning your regular bike into an e-bike is much simpler than you may imagine. It will be an easy process with kits that can make the process a piece of cake. 

Converting a mountain bike into electric: a step-by-step guide will include the 7 basics steps of:

  1. Purchase a bike with smaller wheels and be sure it has no carbon fiber
  2. Purchase an electronic bike converter kit to attach to your standard mountain bike
  3. Remove your bikes bracket using specialty tools
  4. Install a motor unit
  5. Install the battery pack which will charge the motor unit
  6. Be sure all of these parts are connected to function as one. 
  7. Ride your new E-bike! 

Adapting your standard bicycle can be much cheaper than purchasing a full-blown electric bike, which can easily cost thousands of dollars.

Using these amazing conversion kits will help you affordably combine the best parts of a bike and a car to have your very own speed machine.

Make it a weekend project and allow this quick-read to be your ultimate guide! 

Convert a Mountain Bike into Electric: A Step-by-Step Guide

Building your own electric bike will be not only fun but also rewarding. If you’d rather get your hands a little dirty than fuss with wasting your fortune, converting your old bike is the way to go. 

Imagine having a bike that will go up to 40 mph and make your commute home that much simpler. What else could you do with all that time and energy?

When considered in this respect, it’s truly worth the upfront investment if you’re an avid bike rider.

Some of the details you’ll need to consider are:

  • The motor – a common size for e-bike motors is around 750 watts, but others can extend significantly higher. 750 watts should allow your bike to go at least 30 mph without pedal influence.

  • Battery pack – Some argue that ‘bigger is better,’ when it comes to your battery pack, but I argue it will all depend on your preference and intended use. A large battery will help your travels if you’re commuting long distances or need to go for longer without charging.


    If you don’t want to be tied to a wall charger, you may need to invest in a larger battery that can make the bike heavier. One user says he went with a Panasonic 18650 cell, the same that’s in a tesla. I find that completely unnecessary (and probably also not true).

  • The charger – Most kits are going to come with their own charger sets. You’ll want lithium-ion packs that will last longer for you. This may be more expensive up front, but it depends on what’s more important to you – battery life or savings. 

Without further ado, the steps to converting your mountain bike will be as follows:

Pro Tip: Before jumping into a conversion, we’ve got a full article explaining how e-bikes work here to give you a better understanding.

#1 Pick your Bike 

You may be purchasing a new bike or using an old one. These steps will apply to all kinds of bikes, not just mountain bikes, but there are a few things to keep in mind before beginning.

The factors to consider in selecting the right bike type for conversion includes:

  • Be sure it has no carbon fibers – this is because it is too susceptible to weight. You want a bike that is made of strong materials, or else it will collapse under the newly added electric components.
  • Be sure it has smaller wheels – the ideal size for wheel diameter will be around 26 inches (or 66 centimeters). Try to aim for around this size or slightly larger.
  • Be sure it has a strong frame and bottom bracket – some bikes don’t come with these, and it will be essential to the construction process.
  • Be sure it has wider handlebars – this is because of the extra equipment you’ll be attaching to make it electric. If it’s too narrow, the new accessories and connections won’t fit. Simple as that. 
  • Be sure of the disc brakes – Try to find a bike with front disc brakes as that will make all the difference in maneuvering steep landscapes. 

If you’re using a bike you already own, go ahead and try it with that. But keep those factors in mind.  Some kits are adaptable to specific structures, so your bike may simply not be a match. 

#2 Select your Bike Converter Kit

Next, you’ll be purchasing your electric conversion kit. You don’t want to try to construct your e-bike without one of these. Why rebuild the wheel when you don’t have to? 

These kits are optimal because they come with bolt-on equipment, which will include the speed controller, hub motors, and throttle. You can search for these piece by piece if it pleases you, but that’s not the method I would recommend. 

If you are going to do this part on your own terms without the kit, be sure to also purchase brake levers, displays, and gauges if you feel they would aid your construction intentions. 

Things to keep in mind when shopping for your conversion kit will include:

  • Price – you do get what you pay for, so don’t choose the cheapest one you can find. This could damage an already quality bike, and you’re already going through the trouble to convert it yourself. So don’t take the easiest shortcut and try to make your investment wisely. 

  • Size – choose a kit that will match the wheel size of the bike you’re converting. Ensure that the measurements match, but if you do purchase the wrong kit size, it can be easier to change your front wheel versus the back.

    This is because of the gear’s positioning which means you’ll want to select a kit where the hub motor attaches to the front wheel. 

  • Brand name – Don’t focus as much on the brand name as what brand will suit your needs. Every purchase is very subjective, and I can’t tell you what the right kit is for you.

    Do your research and be sure that you’re purchasing from a reputable site that you can return the kit to if it doesn’t fit. 

Below is a video from YouTube recommending the best conversion kits of 2019. If you don’t know where to begin shopping, start with this great resource!

Keep in mind that most of these kits, despite being very comprehensive, will usually not include the battery.  Consider asking for advice at a local bike shop that sells e-bikes.

Timesaver: If you want to cut straight to the chase – one that comes up over and over again is made by bafang. You can click here to check out the Bafang conversion kit on Amazon.

BAFANG Mid Drive Electric Bike Conversion Kits

This is the newest Bafang 7500w BBS02 mid-drive motor kit, including version B motor and upgraded 25 amp controller with 9 IRFB3077 MOSFETs. The Bafang BBS02 kit comes with all necessary parts to convert just about any bike to an electric bike!

Buy from Amazon.com Learn More

Choosing the Right Battery

Selecting the right battery for your kit will mean doing some research on the parts you have. 

You’ll want to purchase between a 36-48-volt battery that has the capacity of between 10Ah and 20Ah (“Ah” stands for amp-hour). These are the measurements for a properly functioning electric bike, so anything less will die quickly or not run quickly, and anything more could damage the entire system and malfunction. 

Be intentional about purchasing a battery made specifically for your intended use and charge before installing. Get familiar with charging the battery as that’s part of the deal in converting your traditional bike. A small price to pay when you have a need for speed. 

The more voltage you opt for, the faster and more powerful your bike will end up being. The Ah rating signifies the length that your battery will last for. So, if you don’t ride for more than an hour or so at a time, the 10Ah will work perfectly fine. If you have to ride home with longer commutes from far away destinations, you’ll need at least the 20Ah battery to get you all the way from point A to B without it dying. 

Also, confirm that the voltage capacity of the battery will sync with the kit you’re purchasing. 

Pro Tip: Purchase your kit and battery from the same distributor if possible. This will make the installation process easier and consolidate any returns/questions you may need assistance with. 

#3 Remove the Brackets

Now that you’ve got all the goodies, it’s time to build! After selecting the proper match of materials, this construction process is actually very simple, similar to changing a tire. You’ll need to remove the bike’s brackets and deconstruct it a bit. 

The steps to remove the brackets are as follows:

  1. Flip the bike over, so its seat is planted firmly on the ground. 
  2. Find the quick-release lever, which will open the security around the wheel. 
  3. Remove the wheel you’ll be changing. The back one should take the battery, but it can be placed on either wheel. Open the cantilever brake if you have one attached to your specific model, and if not, then just the rim. 
  4. Remove the pads that hit where your brakes touch and do so using delicate pliers like needle-noses. 
  5. For the back wheel, you’ll need to hold the frame or have a partner assist you as this may be a two-person step. Pull the derailer backward, and you’ll hear a click unlock the back wheel. 
  6. Unhook the chain or any surrounding attachments to the wheel. 

#4 Install the Motor Unit

Once the original wheel is disconnected, you’ll use the tire and tube, which came in your conversion kit. 

Basically, you’re reversing the last process to put a wheel back on, which will this time have a motor attached to it. 

Putting the bike chain back on can be one of the more difficult parts of the process. I would reference this link for reattaching the chain to utilize visuals, which will simplify the process. 

Properly fit the new tire and close any levers which have been opened. You may need to secure your pads again, which will involve clips or a pin to solidify its new position. 

If the brakes feel off in any way, tighten them by using calipers to align them. If you have mechanical brakes, that will be the only calibration material needed. If you have hydraulic brakes, you may also need to pump the brake lever. 

This may sound overwhelming to you, but it will be much easier when you have the conversion kit. Each comes with specific instructions for you to follow, which will include pictures and specs for that model. It can be difficult to start without seeing the details of your kit, so don’t stress out before then. 

Follow your directions to a T and install any parts they mention necessary. It can be affected by your wheel size, voltage size, intended use, and brand, so giving advice without knowing these details can be difficult.

Connect any gauges or handlebars, and be ready to tackle the battery pack!  

#5 Install the Battery

This is a fun step! Use the directions in your kit again to plug the battery to the connectors you’ve already attached on the wheels. 

Basically – the connector on the speed gauge will connect to the battery. And then they will all connect to the throttle. You may need pliers to aid the process, so don’t be afraid to use extra tools or call for backup.

Warning – do not touch any wires together that don’t mix, or you could risk an electrical spark that could be dangerous. 

If any of this has frightened you beyond belief and you’re over trying to do this by yourself, no shame! Take it to a professional to be certain it’s done properly the first time. 

Keep in mind you will also need a battery box to protect the battery from rain or wear-and-tear. The process will involve drilling some holes and connecting the box. Some cover their battery in foam as a backup layer of protection as well.

Try to get one that is lightweight, so your bike isn’t wasting energy to propel the weight forward. You’ll need to drill the holes for the wires and be careful not to drill into the controller. Do this before inserting the battery pack. 

The battery and surrounding box will be placed somewhere around where you put the water-bottle on your bike. This is an optimal place that will be out of the way and not disrupt your peddling. It also keeps the gravity low and the aerodynamics of your ride intact.

Always follow the instructions that come with your specific battery type.

#6 Connect Them All as One 

This is the easy part! Now you will secure any cables that appear lose and connect them all to your throttle and battery. The start and stop functions are usually attached to your handlebars so you’ll link the wires from wheel, to battery pack, to handlebars.

Some tips that will make this part of the process easier include:

  1. This is perhaps the most important tip in the process – pay attention to everything you deconstruct. Try to memorize what was connected and how it will need to fit back together again. If you’re in a rush to tear it up, you may forget what part fits with what. Take your time and take a picture before construction if this will help you. 

  2. Utilize zip-ties to strengthen the hold around the bars of your bike. You don’t want anything to fall off your bike during mid-run, so this will solidify your construction. Not only could they fall off, but you also risk them getting caught in the wheels as they tumble, which will toss you forward off the bike. (Side note – always wear a helmet for this reason. Don’t make me ask you twice). 

  3. If you’re having trouble with the handlebar part of this guide, some recommend using soapy water to pry the grips open. Use a screwdriver and something slippery that will aid you in wiggling the grips off. Again, you may need pliers to break them loose. 

  4. Leave some slack on the wires you connect to the handlebars. This is what will allow you to turn left and right. But don’t leave enough too much slack, or you risk it getting caught against the front wheel. You can attach these wires with the zip ties or whatever mechanism comes included in your conversion kit. 

  5. The most difficult part of conversion is usually connecting the battery. If it doesn’t end up matching with the rest of the kit you’ve purchased, you’ll need to alter the wire connector that links each part. If you know what you’re doing with a soldering iron, have at it! You can also find electrical connectors or connected wires to make the process even easier. 

#7 Ride Your New E-Bike! 

Without further ado, it’s time to hit the streets and enjoy the fruits of your labor! If you’re ready to take your new e-bike out for its maiden voyage, get ready for more speed, then you’ve ever possessed on a bike before. 

Take your time and ease into it to avoid flying right off or not being prepared. Brace yourself to feel like a superhero, and you’ll quickly realize how much further you can go in less than half the time. It may not even look like a different bike, and others may not know you’ve rigged it, but the speed will be undeniable and save you insurmountable energy.

Don’t Forget to Follow the Law

Also, note that there is some debate about the law on these e-bikes because the government isn’t certain if it should still be considered a bike or if it’s more closely related to a car.  The Federal law states that you can hit speeds up to 20 mph, and the rest of the laws are akin to bike law. Here’s a link on further electrical bike law to reference for your specific state. 

Pro Tip:   charge your battery to about 80-90% and never 100%. This will make the battery last longer and prolong its overall life expectancy.

Final Thoughts

You’ve done something amazing – reconstructed your own bike! Pat yourself on the back because they’ve already proven that biking makes you happier and smarter. So hit the streets and make the most of your rewarding success. The open road is yours, my friend.