The answer to this question is predicated on your ability to handle specialized tools, follow directions, be able to make modifications without comprising the integrity of the bike, have a clear idea of the of the consequences of a poorly converted bike, able to source the correct parts, understand the legal ramification of your conversion, have all of the required tools, and are willing to spend as much time required to insure the finished conversion is a bike that can travel at sustained speeds of over 25mph for an extended period of time. If you can answer yes to all of the following then it is possible that you could build your own electric bike.
This page will give you some sort of an idea of what it takes to do your own conversion. Every bike mechanic that comes to work at our shop has to go through a training period. We never assume any mechanic knows anything at all about motor installation, wiring, cabling, and troubleshooting electric bikes. While hobbyists have been converting standard bikes to electric for the last 10 years no one has done it on a scale we have at Island City Bikes. We know what works and what does not work, we have created a number of novel "work arounds," and many times we have solved obstacles for converting bikes to electric that others have considered unsolvable.
I say all this to help you understand; Never underestimate the difficulties of converting a standard bike to electric. Never stop until you get it right. Never compromise on anything that will affect the safety of the rider. Lastly, patience will be your friend. If you are patience and are willing to spend as much time as it takes to get it right then you will be fine.
“Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.” John Quincy Adams, 1767-1848
Not all bike mechanics are men
"A tool is an object used to extend the ability of an individual to modify features of the surrounding."
Tools have been used for thousands of years by both humans and animals. One could say the development of tools have matched the developmental progress of the human race. Every level of sophistication in product development has called for new tools to measure, view, and build. These tools become as important as the product itself because without these tools the product could not be replicated or repaired. Individuals who master these tools are called mechanics or technicians. Without tools, and our ability to use them, all of our technology would be lost.
To my knowledge, there is no known account of how many different types of tools there are. The list seems endless. How many different types of tools does the average bike shop have? Speaking on behalf of Island City Bikes, we use around 100 different tools in our work of converting bicycles to electric. While that may seem like a lot of tools it what we use on a daily basis. For an example, we have 15 different cone wrenches, 3 types of chain splitters, 6 pin wrenches, 12 freewheel sockets, and on and on. Each tool serves a very specific purpose and without that particular tool our work comes to a complete halt. I will never forget the day a mechanic was working on a conversion and he look at me and ask where a specific tool was that he needed. I said I did not have that tool. He stared at me for a moment, took the bike off the stand and placed it to the side and said, "What do you want me to do next?" I received the message...my job as the owner was to see my mechanics had every tool needed to complete the job.
The following is a review of tools required and how to use them. I hope this is helpful for all who would like to work on their own bike.
Dr. Al Carpenter CEO Island City Bikes
Bikes are heavy and if you are going to work on your bike you have to figure out a way to get it off the ground. This problem is amplified if you are thinking of converting your bike to electric. Once you begin converting your bike you will be wanting to work at eye level and that means either having a means of elevating the bike, or (ugh) sitting on the floor. Even if you choose the sitting on the floor method you will still need to get the bike off the ground to work with chainline, shifting and braking calibration.
A home mechanic bike repair stand can be found for just over a $100 and is a good investment for anyone who is interested in learning to work on their own bike.
This a picture of our heavy duty lift for working on electric bikes. This lift operates on a counter balance located inside the pipe. Electric bikes can be heavy and they get heavier as the day grows long. It is amazing how well this well thought out system works.
The cost of this lift is almost $3,000 with shipping so most home mechanics would not have one of these repair stands.
In addition to the EVT heavy lift repair stand we have two Park Tool electric powered heavy lift repair stands. These also cost around $3,000 each but are indispensable if one is working with electric bikes. Which is our favorite? We have one mechanic that favors the EVT repair stand while others favor the Park Tool electric bike repair stand. The only downside to the Park Tool electric repair stand is they become non functional during a power outage.
That aside, my personal favorite is the Park Tool electric bike repair stand. They are simple to install (sort of) and easy to use.
In order to work on your bike in any capacity, much less install a motor and battery, you have to get the bike off the ground in a manner that is safe. On the internet you can find all sorts of ideas of how to get a bike off the ground in order to work on it. Some of these ideas are clever and others are dangerous. Unless you are 100% certain you can distinguish between clever and dangerous you would be better served to purchase a standard bike repair stand.
In order to install the Bafang mid drive motor the entire bottom bracket, chainring and crank arms must be removed. If you wish to keep your pedals thy need to be removed before removing the crank arms. Over time pedals can become "frozen" to the crank arms and require a lot of force to break the pedals free.
There are two things to remember when removing pedals. First, when removing the pedal on the drive side, turn counter clockwise, towards the rear of the bike. On the non drive side turn the pedal clockwise, towards the rear of the bike. This is assuming the pedals were installed correctly! If not sure look for any indication marks on the pedals that say "L" or "R" then insure they are on the correct side.
The second thing to remember is to always use a pedal wrench and not a crescent wrench, channel locks, pliers or any other tool not designed for removing pedals. Pedal wrenches are designed to remove pedals...nothing else.
This is a home mechanic pedal wrench. It is only around $13 but it has its limitations. It will be fine for removing pedals that are not frozen to the crank arm but pretty much useless if they are. The handle is just to short to apply enough pressure required to remove recalcitrant pedals.
When pedals are installed into the crank arm there should always be a thin layer of grease applied. Some bike assemblers ignore that fact and install the pedals without grease. When this happens the pedals are very difficult to remove. If, the pedals cannot be removed then it might be best to remove the crank arm and have your local bike shop remove the pedal.
We have one of these heavy duty pedal wrenches at every work station at our shop. As you can see it is large and heavy. It also has two different openings; one at 45 degrees and the other 30 degrees. These opens allow us mechanical advantage as we apply force to the spindle.
When removing pedals always remember to take a close look at where your hand is going to land when the pedal breaks free. Make sure your hands will not come into contact with anything once the pedal breaks free.
Removing pedals can be a 60 second job or a 60 minute job. A couple of things to consider. Always use a pedal wrench of some sort and never use any type of substitute. At our shop if a pedal is frozen to the crank arm and it is a $20 or less pedal we do not waste time trying to remove it. It is far more economical to replace the pedals than spend an hour trying to remove a $7.00 pedal that is frozen to the crank arm.
If you are going to install a Bafang mid drive then you need to check your chain for wear. The Bafang comes with a new chainwheel (chainring) and if your current chain is worn then it will skip on the cogset and cause premature wear on the new chainring.
A chain is made up of inner and outer plates, rollers and pins. It is the the rollers and pins that wear out and when they do it gives the impression the chained has stretched. The rollers grow thinner with use and this small tool measures the amount of wear on the rollers. IT is very accurate and an indispensable tool. It retails for around $30.00.
This chain checker tool is also from Park Tool and is less expensive and is just as accurate. The price is around $11.00 at the the time of this writing.
As you can see from the picture above the tool drops down between the rollers. It has two measuring tips. At one end it is .50mm and the other .75mm. If the .75mm end falls through the chain then the chain needs replacing.
While riding a bike under human power you can get away with a lot of mechanical discrepancies. For example, your bike chain can be way past the point it needs to be replaced and it can still be used. It will be noisy and shift poorly but you can still ride the bike. On the other hand, once a bike has a power source, in this case a Bafang 750 watt electric mid drive motor, you can not get away with any kind of mechanical discrepancy. These powerful motors will seek out and exploit any weakness in the drivetrain. A worn chain will result in very poor shifting, be very noisy, and will be subject to fail sooner rather than later.
Now that you have decided to replace the old worn chain the question is: How are you going to remove your old chain? The only way to remove a chain from a bicycle is to use a chain splitter. Chain splitters can be like the one above ($38) or can be of smaller versions that cost less than $10. Just about any chain splitter will do the job.
Modern chains come with a "Quick link" and a chain splitter is not necessary for its removal. However, when you install your new chain it will have to be cut to length and that will require a chain splitter.
A Quick link is a master link that uses a special tool to install and remove. These links are very easy to use and requires no special skills. They just snap on and snap off.
Early on, few bicycle manufacturers would use quick links on their bikes as it was less expensive to pin the chain. Quick links make it easier for bike owners to remove their chain for cleaning. Today, almost all bikes will come with a chain with some sort of a quick link on the chain. Here are some of the names for these links: KMC Missing Link, Connex Link, YBN Safety Link, Shimano Quick Link, and Sram Power Lock. Some of these links are for one time use only while others can be used over and over.
Again, you will not be able to remove the old chain that has any type of quick link unless you have a master link plier. These pliers cost around $15.00 and are made to both remove and install quick links.
Note: Be careful when you buy master link pliers as some of them can install quick links but not remove them. For the price and the fact I know this park tool both installs and removes quick links I would recommend this product. Every work station at Island City Bikes has it set of Park Tool master link pliers.
Before you remove the crank arms on a bike you first have to remove the crank arm bolt. On most bikes this will be a standard 8mm bolt. Park Tool makes a large 8mm hex wrench with a comfortable handle that is designed to remove crank arm bolts.
Crank arm bolts should come off relatively easy but sometimes it require a lot of force. This is why you want to use a large oversized 8mm hex wrench.
Crank arms are held in place by different types of systems. The most common is that used on square tapered spindles. Every square tapered spindle crank arm is held in place by a 8mm crank arm bolt. The Bafang mid drive motor has square tapered spindles so to install the crank arms on a Bafang motor will require a 8mm hex wrench.
This is a self extracting crank arm. The purpose of this system is to make it easier to remove the crankset. One of the problems with this system is that it can be very difficult to remove the crank arm. By design, it is supposed to be a simple method of removal but in practice this type of crank arm can be very difficult to remove and easy to strip the retaining nut.
This is a pin spanner. In Great Britain a wrench is called a spanner and sometimes in the lexicon of tools the two words become interchangeable. This small spanner is used to tighten the retaining nut on the self extracting crank arm BEFORE you begin. The crank arm is removed by turning the inner 6mm bolt clockwise. The inner bolt will push against the outer lock ring until it pushes the crank arm free of the spindle.
Please note: If the outer lock ring is not tight it will become stripped when you turn the 6mm inner bolt. If the outer retaining nut becomes stripped then the crank arm will have to be removed by using a cutting tool.
Now that the crank arm bolt has been removed it is time to remove the crank arm itself. Some crank arms are very difficult to remove and some are permanently frozen to the crank spindle and will have to be cut free. Under normal circumstances this is the tool you will need to remove a crank arm for a square tapered spindle.
Important: Retract the center piece of the tool until it is flush with the housing. Thread the tool completely in the crank arm as far as it will go. Put a crescent wrench on the tool and see if you can get it to go a little further. Then turn clockwise until the crank arm is removed.
If the tool is cross threaded or is not in far enough you will strip the threads on the crank arm. Once the threads are stripped the crank arm will have to be removed by a cutting tool.
Important: Prior to removing any crank arm make sure there is not a washer at the bottom of the crank arm threads. Remove washer before using the crank arm tool as the crank arm cannot come off as long as that washer is in place.
This is the best all around crank arm puller as you can use a wrench to apply much more force than other types of pullers.
Some important things to remember when removing crank arms; Use the right tool, have the bike on the ground (not a lift) as a lot of force will need to applied in some cases, always look to see if there is a washer inside the bottom of the crank arm threads, make sure the tool is threaded all the way into the crank arm, and if a self extracting crank arm insure the retaining nut is tight before beginning.
Removing crank arms is a task not to be underestimated. There has been a few times where we had to use our cutting tools to remove a crankset and it is time consuming. Not only that, we like to return to our clients the parts we removed from the bike in order to convert it to an electric bike. It is always a bit embarrassing to say, "Here is what's left of your crankset."
For the most part, all cranksets can be removed safely and professionally if one has the proper tools, patience, and a willingness to learn the proper procedure. In the event you are faced with a crankset that is simply frozen to the spindle then it might be best to take it to your local bike shop for assistance.
This is a picture of a square tapered spindle bottom bracket. In order to install the Bafang mid drive motor this bottom bracket must be removed. There are many different types of bottom brackets and bottom bracket standards. Each bottom bracket standard will have its own special removal tool. Some bottom bracket standards are: BSA, BB90, BB95, BB86, BB92, BB30, BBRite. OSBB Alloy, BB30A Asymmetrical, PF30, BBrite Pressfit, OSBB Carbon, PF30A, T-47, 386 EVO, 392 EVO, and a few others. In addition to the bottom bracket standards there are varying bottom bracket widths including: 68, 73, 100, 110, and 120mm. Some bottom bracket are eccentric. A eccentric bottom bracket is larger on one side and can be rotated to tighten or loosen a chain. Then, there are bottom bracket diameters. A typical square tapered spindle bottom bracket will have a diameter that will accommodate a Bafang mid drive motor. Other bottom bracket shells will require machining adaptors in order to use a mid drive motor. That is why we have at our shop a machine shop.
This is what a threaded bottom bracket looks likes once it has been removed. The spindle is square tapered and the length is 68mm. It is often covered in grease when removed. Some bottom brackets do not have threads and are pressed in place. These are slowly falling out of favor among cyclists as they have a tendency to squeak. Bottom brackets that are pressed in place require a different set of tool altogether.
Almost all bottom brackets can be removed if one has the right tools and is patient. However, there are times when a bottom bracket is literally welded to the frame of the bike by corrosion. In these circumstances alway take your bike to your local bike shop and have them remove the bottom bracket.
In extreme cases we place the bottom bracket removal tool into the bottom bracket splines, lock the socket in place with a bolt that attaches to the spindle, then we take the frame of the bike and invert it to get the bottom bracket socket in a vice and the turn the bike frame! This will usually free any frozen bottom bracket.
This tool will interface the splines on the bottom bracket. Always start on the non drive side of the bike. Sometimes a bottom bracket will come off easily and if that is the case then use the socket, give it a turn towards the front of the bike (counter clockwise) and it will come free. Once free, move to the drive side and turn it also to the front of the bike (clockwise) to loosen and remove.
Now, here is the problem. The splines on a bottom bracket are very shallow. When the socket is placed on these shallow splines it easily falls off when any pressure is applied. If you continue to try to remove the bottom bracket and the socket keeps slipping eventually you will strip the threads. Therefore you have to lock the splined sockets to the splined bottom bracket in order to to remove the bottom bracket from its shell.
This is how it is done; You take a bolt, run it through the socket and into the axle. This will hold the socket firmly in place and you can supply all the force needed to break the bottom bracket free. We usually lock the socket in place, use a box end wrench, stand on the wrench for leverage and that usually does the trick 99% of the time.
If that fails we use heat, penetrating oil, and the vice when necessary.
Now that the bottom bracket has been removed this is what the bike looks like. Ready for the Bafang motor? Maybe not.
Sometimes, there will be obstructions in the shell that prevent the installation of the motor. In this shell you can see the bolt of the cable guide protruding into the shell. That, of course has to be removed. What you cannot see is the bottom bracket shell has been slightly distorted through the welding process that joins the seat tube, down tube and chain stays. In order to remove any distortion you have to either hand file or use a Dremel to restore the shell to its symmetrical shape. This is painstaking work that can take hours.
This is our tool of choice for removing any obstacles in the bottom bracket shell. It comes in pneumatic and corded versions. We use the pneumatic version as we use long air hoses throughout the shop.
This tool allows us to reach in the bottom bracket shell and round out any distortions without disturbing the threads. We always try to maintain the integrity of the threads in the event the owner of the bike wishes to revert the bike to its original form.
When installing a Bafang mid drive motor it is important that the bottom bracket shell be perfectly square. If not, the motor will pull to one side causing it to bind. This tool is made by Wheels Manufacturing and is relatively inexpensive at around $75.00. The tool is for pressing Press Fit bottom brackets into the shell but it can also be used to determine if the bottom bracket shell is square.
When the the press is is mounted on both sides and tightened, look for any gap between the red drift and the bottom bracket shell. If you see a opening of any size then it needs to be leveled.
This is a facing tool and they are quite expensive at around $400.00. What this tool does is slowly cut away the material from the shell until it is perfectly square. Once it is square on one side, reverse the tool and square the other side.
Now, the motor will set flush in the bottom bracket shell and you can tighten the fixing bolt as much as you want without fear of binding the motor.
Yes, the tool is expensive but if you do not square the bottom bracket shell the motor will sit crooked which will damage the driveline and shorten the life of the motor.
Removal of the bottom bracket might be the most difficult task of doing you own conversion of your bike to electric. The most important thing to remember is to be extra diligent that you are using the correct tool and that it is being used correctly. To use the correct tool incorrectly is the same as using an incorrect tool...both of which can damage the bike and/or cause injury.
First, you will need to order a Bafang kit and a battery. The question is, from whom and where will you find these items? How do you know the source has products that are reliable? Do they offer a warranty? How do you return an item to another country? These are all important questions.
First, the Bafang company does not sell to the general public and they have no outlets in the USA. There is one reseller of their motors in Southern California who uses the Bafang name but they have no affiliation with the Bafang company.
Places you can purchase a Bafang kit include EBay, Amazon, or AliExpress. In addition, there are US resellers such as California eBike, EMPowered Cycles, Lunacycle, and a few others.
That is a very difficult question to answer. I, along with many others in the bicycle industry commit hundreds of thousand of dollars in overseas purchases and have never lost a cent. On the other hand there are many sellers on domestic selling sites that will swindle you out of all they can. In fact I can assure you that if you purchase your Bafang motor kit from a source on AliExpress it will arrive as expected and they will not swindle you.
As a note; Often you will see a fantastic price advertised but when you factor in shipping it turns out the price is not so fantastic after all.
What is the difference between AliBaba and AliExpress? AliBaba is for large orders while AliExpress is for small orders. If you want to buy one motor you would purchase from AliExpress. To purchase 50 or more motors you would purchase through AliBaba.
In a Bafang Motor Kit you will find everything you need to convert your bike to electric except the battery. There will be a chainring (44T or 46T), plastic chainring cover (if it is a BBS02 750w motor), two brake levers with motor cut off, thumb throttle, crank arms (170mm), C965 display, fixing plate, C33 lock nut, locking cap, wiring harness, motor cable, chainring bolts (5), fixing plate bolts (2), speed sensor, and motor (BBS02b or BBSHD).
We have ordered over a 1000 of these kits and have never had a single missing part! The Bafang employees' attention to detail is remarkable. We have never returned a single motor due to damage in shipment or any manufacturer defect.
A lithium Ion battery is regulated as a class 9 hazardous material. Therefore, these batteries must adhere to a strict shipping protocol. Any violation of the shipping of a lithium ion battery can result in a $75,000 fine, levied upon the person identified as the shipper. In other words, if you order a battery from anywhere and it turns out to be defective you cannot return the battery unless you hire the services of a licensed hazard material shipper. Therefore it is imperative you purchase your battery from a reliable source.
If possible purchase your battery locally. In the event there is a problem with your battery you would have the option of returning it for repair or replacement.
Would you pay $600 for this battery? When a sellers sells a battery it is locked in a case with foil stickers that say "opening this case cancels the warranty." The buyer cannot open the case to see if the cells are the ones paid for and the general construction of the battery without voiding the warranty. If the case is opened and it reveals shoddy work the buyer cannot get a refund because the case was opened.
Warranty and refunds...beware. Often we see sellers of batteries promise refunds if the buyer is not satisfied or the battery is faulty and all they have to do is return the battery. The seller knows full well the battery cannot be returned without the services of a hazmat shipper.
Always remember, the purchase of a battery for an electric bike is always a one way proposition; they cannot be returned.
When you purchase a motor you have to have in mind several things. First, which motor? Bafang mid drive motors come in 250w, 500w, and 1000w. They also come in sizes 68mm, 73mm, 100mm, and 120mm. Then there is the chainring. Chainrings in a Bafang kit come in two sizes, 44T (T stands for tooth...I know that it should be plural but it is not), and48T. In addition you need to know which display you would like as there is the DPC965. DPC18, DPC14, DPC500, DPC850, and the DPC961.
If you purchase a 73mm Bafang and you have a 68mm bottom bracket shell, it will not fit. However, a 68mm motor will fit both the 68mm shell and the 73mm shell. If you have a fat bike you will need a 100mm or 120mm Bafang. Measure first before ordering.