How we convert a standard bike to electric
Dr. Al Carpenter, CEO
I came into this business by a circuitous route. I began by building and selling custom bikes intended for racing. It was inevitable that I would encounter a new type of bike called an eBike. After riding an electric bike for the first time, I knew this would be a true paradigm shift in the cycling world.
I began by selling electric bikes that were made by companies whose name I had never heard. These were new companies that were ordering electric bike from overseas, putting their brand name on the bike and selling them. In my opinion, all of these bikes were terrible. They had limited range, very poor hub motors, and the worst components available. At that time there were over 1,500 companies importing these bike to sell in the US. I looked at the bikes I was selling and said..."I can build a better bike."
"The best electric bike in the world is sitting in your garage" is our way of pointing out a simple truth. The only difference between a standard bike and an electric bike is a motor and battery. Most likely, the bike in your garage is a known name brand, fits you and is comfortable, the components are ones you may have chosen when you purchased the bike, and most importantly it is a bike you are familiar with, making it a much safer bike.
Most likely your current bike is one of these brands: Specialized, Giant, Trek, Cannondale, Raleigh, Diamondback, Schwinn, Bianchi, or another well established brand. The point being, all of these bikes have a long history of well documented research, testing, and field testing of their bikes for purpose of reliability and quality. Of the 1,500 new electric bike companies, none of them have any history of quality because they have no history. In addition, many of these new electric bike companies disappear almost as quickly as they appear, only to be replaced by another company willing to ship bikes from Asia and put their brand on the bike.
Almost four years ago, I began converting standard bikes to electric and I was right...the best electric bike in the world is sitting in your garage...it only lacks a motor, battery, and an experienced team of technicians and mechanics to make it happen.
The following is a description of the process of conversion and while it is not comprehensive, as we do much more, it will give you an idea of the process.
Dr. A.L. Carpenter
Steps to an electric bike conversion
No proprietary secrets here...
When a bike arrives in our shop for conversion to an electric bike we view it far more than an exchange of services and goods for financial compensation. We view it as a responsibility and a trusted relationship. I do not say that as a matter of marketing babble but in sincerity. When you place your bicycle in our hands the unspoken message is, "I trust you to transform my bike into a safe, reliable method of transportation for years to come." Every build is personal. We never let any bike leave the workshop that cannot be defined as a "safe, reliable method of transportation for years to come."
Our work does not end when we return your bike to you fully built into a powerful electric mode of transportation. The relationship of trust and responsibility that began at our first meeting will extend into the future. We stand behind our craftsmanship and our product and will always be here if you need us.
Below are some, not all, of the steps a bike will go through to convert your bike to electric. Every bike we convert to electric we test on the roads of San Leandro. Because we ride every bike we build, we know the single most important part of any bike (car or motorcycle), is the tires. The only contact you have with the road is a very small "contact patch" of the tire. It is our professional opinion that all electric bikes should have, for the purpose of safety and comfort, the largest tires within reason. Electric bikes move at higher sustained speeds than a standard bike. These higher speeds require tires with air volume sufficient to absorb the shock from road debris, and obstacles seen and unseen. In addition, tires must be large enough to provide adequate traction for all surface types and conditions.
Meet Isabella one of bike mechanics and former pro cyclist.
Receiving the bike
Evaluating the bike
Evaluating the rider: Age
Evaluating the rider
When a bike arrives at the shop it undergoes a general evaluation to ensure the bike is suitable for conversion. What we are looking for is the condition of the frame, forks, wheels, and any possible corrosion that may lead to failure. Rust on a bike is not necessarily a deal breaker because it depends on how deep the rust has penetrated the frame. Surface rust on a steel bike is common and presents no harm to the integrity of the frame.
We also look at frame geometry. Frame geometry will determine what type of battery we will use and where the battery will be placed.
Then, we look at the area around the bottom bracket. We are looking for any obstructions that may come into contact with the motor. Most obstructions can be removed (bash guards, chain keepers, chain guards). Also, we measure the bottom bracket shell to determine length. Some shells will be 68mm, 73mm, 100mm, and 120mm.
Sometimes we can evaluate a bike with a glance because we have built the same bike many times over. Other bikes will take a deeper examination. For example, a carbon fiber full suspension bike. Carbon fiber can be shaped and molded whereas aluminum and steel is predictable. The Bafang motor will fit any bottom bracket shell of steel, aluminum, and titanium, but carbon fiber bikes may have a bottom bracket shell that is irregular in shape that may prevent the use of a mid drive motor. See our article on the Bafang motor and carbon fiber bikes.
NOTE: Do not be concerned if your bike is dirty! We will clean your bike thoroughly when it is in our possession.
Evaluating the rider
Evaluating the rider: Age
Evaluating the rider
When someone brings a bike to our shop for conversion we want to know as much as we can about the rider of the bike as well as the bike itself. The bike is a static, non-living object whose value (other than its artistic value) comes into being when it becomes one with the rider. Therefore, it is rider first and bicycle second.
The who question is a question of responsibility. I have been ask to build electric bikes for children as young as seven. The parent tried relentlessly to convince me the child could manage an electric bike that could travel up to 30mph. Of course, I held my ground and refused and certainly hope other builder also refused. An electric bike is fast and requires focus every time a person is on the bike...even if it is not moving.
Once, a man called me to ask if I could build him a bike that can go 40mph. I said that I could and then asked for what purpose would he need a 40mph bike? He replied, "I just got my forth DUI (Driving under the influence of alcohol/drugs) and lost my license and now need a fast bike to get to work. I informed him that I would be willing to build him a 20mph bike, but nothing more. He said he would find someone else who would build the bike for him.
Sometimes, it is time to hang up the cycling shoes. A man with dementia came to our shop and said he wanted us to convert his bike to electric because he kept falling off the bike every time he stopped pedaling. He thought converting it to electric would solve his problem. Of course the problem was not the bike and converting it to electric would not be the solution. He was 97, loved cycling and had reached that stage where...well if you have cared for an aged parent then you know what I am talking about and I will leave it at that.
Evaluating the rider: Age
Evaluating the rider: Age
Evaluating the rider: Age
Age is not always a limiting factor when someone comes to our shop requesting their bike be converted to electric. We have converted bikes to electric for at least a dozen riders over 90 years of age within the last two years. Albeit, all of these riders have a long history of cycling and are very experienced cyclists. Some have cycled around the globe and across the US several times. Others are former racers. This group of elders may have many decades behind them yet they are still athletes in body and soul. In addition, their collective knowledge of cycling throughout the years under diverse conditions is encyclopedic. Their bikes are always well maintained and may even be of a different era but they always make for great eBike conversions due to their fantastic condition.
The point is, electric bikes will not pose a danger to a rider over 80 who is an experienced rider and in great shape both mentally and physically. And, as we all know, there are some who are 80 plus who are in better shape than some of us who are much younger.
Now...the other side of the coin. Sometimes age is a very limiting factor. Three times this year (2020), I had to meet with the families of men who requested we convert their bike to electric. Each time I said the same thing; "I am sorry, but your (insert relation) should not be on any bike, much less an electric bike." Those were difficult meetings but in each case the family members were in agreement. One time a spouse said to me, "Of course you are right but he would not accept the fact he should no longer be on a bike unless it came from a professional."
Yes, it is uncomfortable saying "no" to an adult. However, we are all responsible for one another's well being, as we should be. Profit stands far behind character, integrity, and human decency.
cleaning the bike
Cleaning the bike in three stages
Cleaning the bike in three stages
Cleaning the bike in three stages
It is not possible to inspect a bike without cleaning a bike. No bike should ever be converted to electric without a thorough inspection, and an inspection is not possible without a detailed cleaning. Cleaning a bike is hard and dirty work, but it is part of the process of conversion and cannot be eliminated.
Every employee of Island City Bikes (except office staff) are informed at the time of employment they will be involved in cleaning of bikes. We are out cleaning bikes in the hot sun and in the pouring rain, but in the end...there is nothing about your bike we do not know.
Yesterday, I asked one of our mechanics if she enjoyed cleaning bikes and she said, "Yes, because I like to see a bike restored to its original beauty."
We do not see a dirty bike as a reflection of its owner. A dirty bike is a bike that is being used and enjoyed. As a result, it becomes covered in dirt, grime, mud, and other contaminates.
What we find cleaning a bike
Cleaning the bike in three stages
Cleaning the bike in three stages
This material was found inside a tire. What is it? It appears to be a tire liner that crumpled with age. Of course, this material would grind the tube until there is a sudden blow out.
How did we find this material? We found this because we removed the tire in order to inspect the rim tape. Rim tape is a cloth (my favorite) or plastic strip that sits over the spoke holes on a rim. Rim tape must cover all the hole lest the tube extend into the hole causing a blowout.
Some of the items we have found while cleaning a bike include; cracked frames, broken derailleur pulleys, tubes with multiple patches, damaged rim tape, broken spokes, bent axles, out of round wheels, worn bearings, cracked tires, missing parts, worn brake pads, chains that are seriously worn, parts assembled incorrectly, broken stems, cracked stem faceplates, broken saddle rails, recalled front forks and recalled rear suspension.
All of the above can go unnoticed unless a bike is thoroughly cleaned and inspected.
Inspecting rim tape
Cleaning the bike in three stages
Rim tape has shifted
This is an example of rim tape that needs replacing. That small hole will get larger and when it does, the tube will expand into that hole and the tire will blow out.
Electric bikes can ride at sustained speeds of over 25mph. A blowout at that speed can have serious consequences. Rim tape does not last forever and will need replacing at some point. Fortunately, rim tape is inexpensive and simple to install.
Yesterday, a child's bike came in for repair. Normally, we do not work on any bikes other than our clients'. We make an exception to this rule if it is a child's bike. On this bike it was a flat tire in need of repair. I pulled the tire off for inspection and the first thing I noticed was the absolutely terrible rim tape that was installed. It was twisted and a third of the spoke nipples were visible. These exposed nipples will cut the tube resulting in a sudden loss of pressure. Difficult to believe someone, somewhere thought it appropriate to do such poor work on a child's bike.
Rim tape on all bikes needs to be periodically inspected.
Rim tape has shifted
Shift and Brake Cables housing
Rim tape has shifted
This is a picture of rim tape that has moved. As a tire flexes it can catch on the rim tape and move it to one side or the other. As you can see, this rim tape provides no protection at all and is subject to a blowout at any time.
If you have read much about the way we build bikes you will know we are very tire centered. Tires are the most important part of any bike as it is the only part of the bike that comes into contact with the riding surface. Tires must be of good quality as must the tube and...the rim tape. If the rim tape fails to protect the tube then it does not matter how thorn proof your tire is, you will still get a flat, or worse, a blow out.
Rim tape comes in a variety of materiel. The lowest grade rim tape is a black rubber strip that stretches over the rim. This is often found on department store bikes and it should be removed and replaced. There is also plastic rim tape that is stretched over the rim, and can last for years. Our favorite is cloth rim tape made by Velox or Newbaum. This tape rolls onto the wheel and then it is cut to size. It is very strong and lasts for many years.
Broken cassette
Shift and Brake Cables housing
Shift and Brake Cables housing
This cog has a broken tooth. We found it because we removed the cassette, separated all the cogs, and cleaned each one independently. Why did the rider of this bike fail to notice the broken cog? It would be almost impossible for the rider to spot this damage because it was covered with grease. We would have missed it also had we not disassembled the cassette for cleaning.
Would this broken cog create a safety issue? While it would not present a safety issue, it would affect shifting. That small wavy protrusion on the cog is a "ramp" that moves the chain from one cog to the next. If a tooth on the cog is broken the chain will stretch between the two good teeth and this can damage the chain. Under human power, a rider could ride with the broken cog with little fear of chain damage. However, under the power of the Bafang 750 watt motor, a broken tooth on a cog can damage a chain, which in turn will damage the chainring.
Most bikes will never have the cassette removed and inspected. It should be done annually. However, it does require special tools and can be hazardous if not done properly.
Shift and Brake Cables housing
Shift and Brake Cables housing
Shift and Brake Cables housing
A bit hard to see...the shift cable housing on this bike is rusty and needs replacing.
Shift cables and shift cable housing are integral to the shifting of your bike. Brake cables and brake cable housing are essential for stopping your bike. It is our job to insure that every bike we convert to electric has sufficient braking capabilities and can shift between gears smoothly. In order to do this, the bike has to have good cables with clean cable housing. We have seen many bikes where the cables have been replaced but never the cable housing. Using new cables in old housing is always a mistake. We inspect each cable and cable housing to determine if either needs replacement.
When we inspect cable housing we are looking for rust, kinks, damage to the housing, unnecessary bends, and length. Many times we find shift/brake housing that is too long or too short. We also replace old end caps on housing. End caps wear out just like any other part on a bicycle and should be periodically replaced.
Cleaning the bike - continued
Shift cable
Tire and tube inspection
Tire and tube inspection
This shift cable would have broke in short order leaving the rider stranded. Can a snapped shift cable pose a danger? Yes it can. When a derailleur cable snaps, the chain immediately falls into the lowest cog on the cassette. If you are climbing a hill when this happens, you will most likely will fall off the bike. In addition, if the "limit screw" on the derailleur is not properly set, the chain will wedge itself between the frame and the wheel. If that happens it is very hard to correct.
If, your bike has a "Rapid Rise" rear derailleur then the chain will go to the largest cog on the cassette. That is fine except for the fact if the low limit set screw is improperly set, the derailleur will go into the spokes and a crash is imminent.
Some shift cables are made of galvanized steel and they cost a third of stainless steel cables. Whenever we see a bike with galvanized cables we remove them and replace with triple strand stainless steel cables. Galvanized cables quickly erode and contaminate the cable housing.
We always check cables, cable housing, and limit set screws on every bike. Many times, we find bikes where the limit screws are not set and the derailleur is held in place by the tension of the cable. It is done in this manner because it is much faster than using the limit screws. Always...use the set screws on the derailleur, as it is the only thing that will prevent a chain from falling into the spokes, or wedging between the cassette and the frameset.
Tire and tube inspection
Tire and tube inspection
Tire and tube inspection
The slanted valve stem is a problem that needs to be addressed, not ignored. This Schrader valve stem is being pulled against the sharp edge of the rim and eventually it will cut the stem, resulting in a flat tire.
A flat tie is not just an inconvenience...it can also be hazardous. Tires rarely go flat while they are sitting at home. Tires can go flat while riding in the rain or in the summer heat, in a high traffic areas, in dangerous areas, or on a steep hill. Not everyone knows how to repair a flat. With that in mind, whenever you have a stem that is slanted, treat it as if you already have a flat and have it corrected. Otherwise, you may have a flat at the most inopportune time.
The slanted stem occurs when the rubber inner tube sticks to the inside of the tire. As the tire flexes and moves, the tube, being affixed to the tire, also moves.
To prevent this from occurring, we remove the tire, put the tube in a bag with baby powder and shake (not us...the bag). Now, the tube being covered with baby powder will not adhere to the inside of the tire and the stem should remain straight. Will this solve the problem? Sometimes yes and sometimes it only delays the inevitable. The best way to solve the problem is to use a tube that has the small nut on the valve stem.
Tire inspection
Tire and tube inspection
Frame inspection
There is nothing more important on any electric bike (or any bike for that matter) than the tires. Tires are the only part of a bicycle that comes into contact with the riding surface. Tires are more important than brakes. Tires are what stop a bike, not the brakes. Brakes hold the wheel while the tires stop the bike.
The RV dilemma. Many have purchased a used motorhome that had tires that looked new and had very low milage on them only to find out each of the tires had to be replaced. The usability of a tire is never based on appearance...it is based on age.
When we inspect a tire we look at the sidewall, as the sidewall is the first place that will show degradation due to age. Then we look at the surface of the tire. The surface of the tire is where obvious signs of wear are visible. If we see too many holes or imbedded material we recommend replacement. If the tire tread is worn, it needs replacement.
Please note: Never rotate tires. Sometimes, a rear tire that is worn will be rotated to the front and the front tire to the rear. This practice is not accepted by any school of bike mechanics.
Tires are a consumable, and it is to be expected they will need replacing as a matter of safety.
Frame inspection
Frame inspection
Frame inspection
Bike frames are made of steel, aluminum, titanium, and carbon fiber. Each of these materials comes in different grades and thickness. With metal frames we pay close attention to the welds (brazing) of the frames to ensure there are no hairline cracks. We are also looking for any previous repairs that may not be up to snuff. We have a frame builder on call to evaluate any frame we think might be a problem.
Bike frameset are incredibly well made. That is why most manufacturers provide a lifetime warranty on their frames. However, that does not exempt from close inspection as there are frame failures! We pay special attention to seat tube and chainstays as these are more prone to failure than any other part of the frame.
This inspection is part of our cleaning process, as it is not possible to inspect a frame for small hairline cracks when it is hidden by road grime.
Fork inspection
Frame inspection
Wheel inspection
The one component we see on recall lists more than any other is the front suspension fork. While cleaning the bike, we inspect the fork to ensure it is working properly then we check the recall lists to see if it is a recalled fork. Last year we found four front suspension forks that were on a recall list, one of which was an "imminent danger of failure" recall. In each case we helped our client file a claim for new forks.
When a factory recall occurs, all dealers are notified. The dealer is supposed to contact all those whom he/she sold the product and notify them of the recall. Sometimes that does not happen. Other times, the bike is sold to another party and they do not know there was a recall in effect.
A bit of research on our part helps our clients have a safer bike for a safer ride.
Wheel inspection
Frame inspection
Wheel inspection
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First, we look at the rim tape. Does it cover all the holes, or the spoke ends? Is it poor grade that will eventually fail? Has it slidden out of place? Does it impede the valve stem? All of these factors will affect the life of the tube.
Second, we clean and inspect every spoke. We look at the point where the spoke enters the rim. It is here where we find cracks as the tension of the spoke tries to pull it through the rim. Then we move to the hub. It is at the hub where spokes tend to break. We hand squeeze each spoke to see if any or loose or even broken.
Third, we look at the bearings...does the wheel spin smoothly on the bearing? Do the wheels wobble? If a wheel wobbles we put it on a stand and correct the bearing tension. If a wheel spins in an irregular fashion (difficult to explain) then the bearings need to be loosened (if cone and cup) or replaced.
Cleaning the components
Cleaning Tank
Derailleur Pulley or Jockey Wheel
Derailleur Pulley or Jockey Wheel
We use a parts cleaning tank to remove the thick grease that is found on derailleurs and cassettes. We lightly spray the components with a biodegradable solvent and brush with a cleaning brush. This process removes all of the heavy debris and readies the component for ultrasonic cleaning.
The rear derailleur is the part that requires special attention. First, we take a small pick and shave off as much as the grease/oil from the pully wheels, and inside the cage. From there we take the derailleur to the cleaning tank and use a brush and solvent to further remove the sticky grease. One the initial cleaning is finished we can inspect the rollers to see if they need replacement.
Derailleur Pulley or Jockey Wheel
Derailleur Pulley or Jockey Wheel
Derailleur Pulley or Jockey Wheel
Yes, this is what some pulleys look like on a heavily contaminated derailleur. This is why we use a prewash before we use ultrasonic cleaning. Sometimes we will replace the pulley wheels if they are damaged. However, if these are not cleaned and then inspected, one would never know they need replacing. Any bike that has pulley wheels that need replacing will never shift smoothly.
If the derailleur is of good quality, we replace the wheels if needed. The Sram 3, Shimano Altus, and a few other entry level derailleurs, we replace the entire derailleur. These are good derailleurs it is that the pulley wheels are not replaceable.
Ultrasonic Cleaning
Derailleur Pulley or Jockey Wheel
Ultrasonic Cleaning
This is a commercial grade ultrasonic cleaner. Ultrasonic cleaners use high pressure sound waves to create minute cavitation bubbles that force contaminates from objects placed in the tank. We use a biodegradable cleaner in conjunction with the ultrasonic cleaning tank. Nothing can clean a chain, derailleur or cassette better than ultrasonic cleaning. It is through the use of ultrasonic cleaning that enables us to find small things such as cracked pulley wheels in the derailleurs. What is nice about these machines is you use safe, biodegradable, cleaning solution. We use this machine everyday and it is one of the most important tools in our shop. You find this same machine in jewelry stores, although they are much smaller than ours.
Lubrication
Lubrication
Ultrasonic Cleaning
After we finish the ultrasonic cleaning we inspect and remove any strings from the pulley wheels. Pulley wheels are magnets to string and hair and they have to be cleared for them to spin smoothly. If, when we spin the wheel we find it to be gritty we dissemple the wheel and clean the small circular groove. If there is too much play, that means the bushing is worn and the pulley needs replacing.
Now, we lightly lubricate each pivot point of the derailleur. It is almost impossible to correctly lubricate a derailleur while it is on the frame.
Before installing the derailleur, we take our Park Tool Dag-2.2 Hanger Alignment Guide and check the hanger to insure it is not bent. 80% of all bikes that come into our shop have a bent hanger. A bent hanger will affect the shifting. If the hanger is correct, we we apply a touch of grease to the threads and install the derailleur.
Chain
Lubrication
Cassette
Dirty, greasy bicycle chains are...normal. They simply cannot be avoided when you keep your chain lubricated. Chains that are lubricated attract dust and grime. We clean these chains for a couple of reasons. First, we do not like to work with dirty chains. Second, it is poor form to put a dirty chain on a new bike. Every bike we convert to electric has either a new chain or the original chain that has been cleaned and lubricated.
NOTE; We inspect/measure every chain. An electric motor will overpower a worn chain causing it to "skip" on the cassette. It will make a loud popping noise. To check the wear on a chain we use the Park Tool CC-2 chain checker.
We use a dry lubricant and wipe as much off as possible. To much oil on a chain will attract dust, dirt, and road grime which will cause premature chain wear. Chains are not expensive and they are considered a consumable. It is best to plan to replace your chain every year. This will prolong the life of your chainring and your cassette.
Cassette
Lubrication
Cassette
This is not a new cassette...this is a cassette that was covered in grease and grime. We disassemble each cog, separating the cogs and spacers and then put them in the ultrasonic tank. After six minutes they were removed, hand dried and then inspected. While the cassette is off the bike we clean the cassette freewheel body that is on the wheel. After cleaning, the cassette is resembled and placed on the wheel.
On some occasions we will clean the cassette on the wheel. The reason is the cassette can become frozen to the hub. This occurs when the cassette was initially installed the mechanic did not apply grease to the threads. While we can remove any cassette from any bike, a frozen cassette requires tremendous force and in the process may destroy the wheel. If the cassette is visible worn, or damaged, we then discuss the options with the owner of the bike before proceeding.
On the work stand
Disassembly of Bike
Removing the Crank Arm
Removing the Crank Arm
We have 4 heavy lift workstands to safely lift any bike. Each workstand grips the seat post and raises it to a height of up to 6 feet. This allows us to work on your bike at eye level. When the primary cleaning process is finished, the bike is assigned to a mechanic and a workstand. The bike will remain with that mechanic and work stand until the conversion is complete. At that time the work will be examined by a second mechanic prior to the test ride.
When the bike is on the stand we begin the process of disassembly. We will remove the pedals, crank arms, crankset, chain, cassette, derailleur, bottom bracket, front derailleur, front derailleur shift cable, front derailleur shifter, left grip, left brake lever, and front and rear wheelset.
While the wheels are removed we inspect the brake pads on disc brake systems and brake shoes/inserts if rim brakes.
Removing the Crank Arm
Removing the Crank Arm
Removing the Crank Arm
In order to install the Bafang mid drive we will need to remove the crank arms, crankset, and the bottom bracket.
There are several different types of crank arms and each requires a special tool and technique for removal. The picture above is a self-extracting crank arm. These were made to make their removal simple and fast. Sometimes they are simple and fast to remove but around 70% of the time they are very difficult to remove.
Around 5-10% of the time we encounter frozen crank arms, or crank arms where the threads have been previously stripped or cross threaded. In such cases the crankset has to be removed by careful use of power cutting tools.
The most common bottom bracket spindle is the square tapered spindle. The Bafang mid drive motor also uses a square tapered spindle but the crank arms are not interchangeable, with some exceptions.
Removing the Crankset
Removing the Crank Arm
Remove the bottom bracket
The picture above is of a triple crankset with a square tapered spindle. When we remove the crankset we do so carefully as we do not to strop the threads. We start of with a special tool called a thread chaser. The thread chaser cleans and straightens any threads that might be damaged. The we carefully thread in our second tool, the crank puller. This tool we thread in a far as it will go. If this tool is not all the way in, it will strip the threads once the removal tool starts pulling.
Removing a crankset can be accomplished in 10 minutes if the correct tools are used with the correct procedure. Failure means at least an hour of work cutting off a crankset because the threads were stripped in the process.
However, there will be those cranksets that are permanently frozen to the spindle and the only path to removal is through the use of powered cutting tools.
Remove the bottom bracket
Check the derailleur hanger
Remove the bottom bracket
There are many types of bottom bracket removal tools because there are many types of bottom brackets. The above picture is perhaps one of the most common and works with most square tapered spindles.
It is very easy to strip the threads in a bottom bracket. In order to prevent that from happening, we insert the socket into the bottom bracket splines, and then we use a tool to lock the socket tight against the splines. Then we can apply as much force as necessary to remove the bottom bracket.
Bottom brackets can be frozen into the bottom bracket shell. We see this in both old bikes and new bikes and they are very difficult to remove. We use several methods including heat, chemical solutions, counter force, overnight soaking, and so far we have yet to be defeated. If a bottom bracket cannot be removed it cannot be converted, so one way or the other...it has to go.
Check the derailleur hanger
Check the derailleur hanger
Check the derailleur hanger
Almost all bikes have a derailleur hanger. A derailleur hanger is a detachable hanger that holds the derailleur. It is made of softer metal than the frame. If the bike falls or crashes on the derailleur side of the bike, instead of damaging the frame, it bends or snaps off the hanger. A derailleur hanger costs $15-$20 whereas a damaged frame can thousands. This part is called a sacrificial hanger because it is sacrificed to protect the frame.
90% of all bikes that we see have a bent derailleur hanger. Anytime a bike is loaded into a vehicle and lays on the derailleur side it can bend the hanger. They bend easily, as they should, to protect the frame.
We check every hanger with the Park Tool Dag 2.2 Alignment tool. A bike with a bent hanger will never shift smoothly regardless of how much you adjust the cable.
Tire Inspection
Check the derailleur hanger
Check the derailleur hanger
I have written a great deal about the necessity of tires on an electric bike. The wider the tire, the greater contact patch is with the surface, thus better stopping power! Larger tires make for a much more comfortable ride. Also, larger tires act as suspension on bikes. Suspension is important when riding a bike that can travel at sustained speeds of 25mph. Bumps, potholes, and obstructions in the road can come up fast and sometimes the only protection you have against a crash is large tires to absorb the shock.
Tire have to be in good condition. Stock tires, that came with the bike, are often found wanting and should be replaced with better tires. Old tires may appear in great shape with lots of tread but once we remove the tire from the wheel and look at the sidewalls we ofter (always) find age cracks throughout the tire! Tires have to be stored in a dark place, on a bike that is suspended, with the tire not sitting on the ground.
choosing the right motor
The motor we use
Why do we use the Bafang motors exclusively?
Why do we use the Bafang motors exclusively?
The Bafang color is known throughout the world. When you attend a trade show, look for the big orange sign and you know you have found the Bafang booth.
The Bafang company sells over 1,000,000 motors a year and is the largest manufacturer of electric bike motors in the world. It might be noted that Bafang was first named 8Fun motors and that is why you still see the word "8Fun" stamped on some crankarms and chainring covers. 8Fun is an odd name to the ears of Westerners. The number eight has always been the number of good luck or good fortune, and the word "fun" is a reference to direction; when used together it means: Good fortune in eight (many) directions. Makes sense when you think about it. Wherever this motor takes you, may it bring you good fortune.
Why do we use the Bafang motors exclusively?
Why do we use the Bafang motors exclusively?
Why do we use the Bafang motors exclusively?
Easy question. If anyone can show me a better motor at any price and I will switch to the other motor. Still waiting....sound of crickets....
We have converted nearly 2000 bikes to electric at the time of this writing, and we have seen only two motors burn out, which was not the fault of the motor...it was the fault of the riders. Both times it was a rider climbing a very steep hill using the throttle in the highest gear.
These motors are simple and yet very powerful. Believe it or not, there is only around 20 parts to this motor. It is very simple in design and because of this simplicity, there is not a lot that can go wrong. Simplicity always trumps complexity and that can be applied to just about everything.
The Bafang mid drive is so powerful we constantly have to adjust the power to the rider. The motor is so reliable we offer a one-year-no-fault warranty. It is a safe bet for us because we know the exact failure rate of these motors and it is near zero.
The Bafang BBS02b 750 watt motor
Why do we use the Bafang motors exclusively?
The Bafang BBS02b 750 watt motor
This is a Bafang BBS02b 750 watt motor.
Weight: 8 pounds
System voltage: 48v
Power output: 750 watts nominal
Power output Peak: 1150 watts
Maximum current: 25 amps
Throttle and peddle assist
Torque: 160NM
Speed sensor
electric brake equipped
Shift sensor equipped
NOTE: This motor weighs 8 pounds and a hub motor with similar output will weigh over 50 pounds.
The Bafang BBS02b 750 watt motor will fit the riding needs of 90% of riders. Remember, the maximum size motor allowed in Europe is 250 watts and in Canada it is 500 watts. A 750 watt motor is triple that allowed in Europe and if that does not supply the necessary power for an electric bike, then nothing will. Remember, anything over 750 watts is illegal for use on any public road in America.
The Bafang BBSHD 1000 watt motor
The Bafang BBSHD 1000 watt motor
The Bafang BBS02b 750 watt motor
This is the Bafang BBSHD 1000 watt motor. The "HD" designation means heavy duty.
Weight: 12 pounds
System voltage: 48v
Power output: 1000 watts nominal
Power output Peak: 1500 watts
Maximum current: 30 amps
Throttle and peddle assist
Torque: 190NM
Speed sensor
electric brake equipped
Shift sensor equipped
The Bafang BBSHD 1000 watt is a heavy duty motor for off road use. This motor sheds heat better than the BBS02 750 watt motor but is also heavy, slower, and more expensive than the BBS02 750 watt motor. We always recommend the BBS02 because it is lighter, costs less, and is legal for road use.
Maintenance free motor
The Bafang BBSHD 1000 watt motor
Maintenance free motor
Dang...nothing to do with this motor.
People always ask what kind of maintenance they will need to do on their Bafang mid drive motor and the answer is...nothing. There is nothing you can do other than ride the bike and enjoy the power and simplicity of this motor.
Some like to open the case of the motor and add grease to the gears but that is not necessary. Also, there are some who replace the nylon gears with metal gears thinking it will make the motor last longer. It will not make the motor last longer...it will just make it noisier.
For those who like to tear down their motors and replace the parts, it is a fairly simple process. They are not like combustible engines, they are electric motors and every part can be replaced at some point.
Bafang competitors
The Bafang BBSHD 1000 watt motor
Maintenance free motor
Competition for some is the the only driving force behind innovation. Other companies stay so far ahead of the competition that it matters little. To the best of my knowledge, at the time of this writing, there is no electric bike motor manufacturer that is remotely close to producing a better motor than the Bafang BBS02b and the BBSHD 1000.
This powerful, lightweight and maintenance free motor is relatively inexpensive because the Bafang factories (more than one) produce over 1,000,000 units a year.
Personally, I do not think there will be a challenger to the Bafang motor for a long time to come. Its versatility, availability of parts (worldwide), cost and simplicity make it a very tough motor to challenge for its market share.
the build - continued
Which motor should I use?
Which motor should I use, continued
Which motor should I use, continued
The answer to this question lay within as to what type of riding do you plan to use the bike. If you intend to use your bike off road, then you can use either the Bafang BBSHD 1000w or the BBS02 750w. If you plan to use your electric bike on public roads and bike paths, then we strongly suggest the BBS02 750, as that is your only legal option. However, it is your bike and your choice...we can only inform and advise as to the laws that regulate the use of electric bikes.
We have found the 750 watt motor meets the needs of 90% of all riders. We base that on the input we receive from all of our clients that are on bikes we built with the 750w motor.
We have installed the Bafang 750 on many heavy cargo bikes and yet to have a single motor fail. These are heavy bikes, often are used to carry children and yet the Bafang 750 is up to the task.
Which motor should I use, continued
Which motor should I use, continued
Which motor should I use, continued
It simply is not true that the Bafang BBSHD is a better motor than the BBS02. The only people I know who make such a claim are those who sell the BBSHD. Yes, power comes from the motor but a mid drive motor climbs not with just brute force, but through the combination of front chainring and rear cogset. For example a 750w motor with a 36T chainring and a 11x36 rear cassette will out climb any BBSHD.
The other day I was talking with a Bafang reseller and I ask, "Selling many HD'S?" He looked at me and replied, "The HD is my number one seller." Think about that for a moment...The Bafang BBSHD is illegal in all 50 states for road use, is used by no eBike manufacturer, is heavier, slower and is more expensive than the BBS02 750, but it is still his number one seller. The reason for this is it is promoted by all resellers of Bafang motors as a better motor. It isn't. We have built hundreds of bikes...we know what is the best motor from hard data of actual bikes on the roads....no marketing, no opinions, no guessing...we know what works and what does not work.
Legal classification of your bike
Which motor should I use, continued
Choosing a right battery for your bike
All electric bikes are regulated by Federal and State law. There are three classes of electric bikes and when we convert your bike to electric, we give you the opportunity to choose which class of bike you would like.
Class I: This is a bike that does not have a throttle and the motor assist cuts off when it reaches 20mph.
Class II: This is a bike that has a throttle and the motor assist cuts off at 20mph.
Class III: This is a bike that does not have a throttle and the motor assist cuts off when it reaches 28mph.
It is your bike and it is your choice what type of electric bike you would like us to build. You can change your bike at any time, as the process of converting from one class to another is as simple as reprogramming the controller of the motor.
Choosing a right battery for your bike
Choosing a right battery for your bike
Choosing a right battery for your bike
We have a number of batteries to choose from. The standard battery that comes with our electric bike conversion is a 48v 13 downtube battery. This can be upgraded to a 48v 17.5Ah or a 52v 17.5Ah battery. The larger the battery the greater the range. Most of the bikes we convert use the 48v 13Ah battery and it seems to provide sufficient range. We know this because only two people have returned and requested a larger battery.
Note: Sometimes a client does not get to choose the battery if the frame geometry dictates the shape/size of the battery. When we work with full suspension bikes often (not always) the only battery that will fit is our 48v 10.5 side release battery.
The 48v 10.5 Side release battery
Choosing a right battery for your bike
The 48v 10.5 Side release battery
This is the side release battery and it is our favorite battery. The cell group is Samsung 35E and it makes for a great long range, light weight battery. It weighs significantly less than most downtube batteries and yet still is very powerful because of the Samsung 35e cells.
The design of this battery allows it to fit in tight places. Most downtube batteries slide from the top down and this requires a distance on the top tube to be greater than the battery base plate. Whereas on a side release battery, if the base plate fits the battery will fit. We also like to use the side release battery when we are placing the battery on top of the top tube because it is much lighter than the 48v 13Ah battery.
52v or 48v battery?
Choosing a right battery for your bike
The 48v 10.5 Side release battery
We build a fair number of electric bikes with 52 volt batteries but that is because it is what our clients request. However, if you wish for your motor to provide years of trouble years service then we always recommend 48v batteries.
It is true that a 52v volt battery will make an electric bike faster and will increase range but the downside is that it can prematurely wear our the motor and the drivetrain of the bike.
Every Bafang mid drive motor is rated as a 48v system. That is the way it was designed by the engineers at Bafang . To stay within the design parameters set by the engineers of Bafang will provide you with years of trouble free riding.
attaching the battery to the frame
The Golden Standard
Water Bottle Inserts
Water Bottle Inserts
The gold standard of battery placement is to attach the battery to a frame that will be a solid connection with as little movement as possible. Some frames are small round steel tubes. These are the most challenging. Other frames may be shaped aluminum tubes with a relatively flat surface. These are the best to work with. It does not matter the size, shape, or material of the frame, it is not allowable to connect a battery to a frame in such a manner it will ruin either the battery, the frame or both. The most common error we see from others is using a battery that is too heavy for the shape and/or material of the bike frame. A nine pound battery is too much weight for small steel tubes or carbon fiber frames.
Over the years we have developed solutions to most of the problems associated with interfacing batteries with frames of different sizes, shapes and material.
Water Bottle Inserts
Water Bottle Inserts
Water Bottle Inserts
Typically, a battery is attached via the water bottle inserts. However, often these inserts may not line up with the battery base plate or their use may place the battery in a location that is to close to either a moving part, or a static part that may damage be housing of the battery as it rubs against it. In that case, we use adaptors.
Most of the adapters we use we machine for our own use. Every bike is different and that means many different types of adaptors. Over the years we have experimented with aluminum, rubber, leather, and other materials. One time a bike came in that was manufactured by a well known company and the owner wanted us to convert it to the Bafang system. On tearing down the other companies system I found they used a half of a wooden clothespin along with industrial glue to make a frame spacer for their motor. Interesting. I think would have used a bamboo clothespin as they are more resistant to wear but I thought the idea itself was sound.
Use of Rivnuts
Water Bottle Inserts
Use of Adaptors
The above is a picture of one of the tools we use for the installation of Rivnut. A Rivnut is the same thing as a water bottle insert. The installation of Rivnuts on a bicycle frame is a very important skill. Sometimes, due to the existing position of the water bottle inserts, a Rivnut has to be installed in order to get the battery secured to the frame. The installation of a Rivnut require drilling a 4mm hole into the frame then installing a 5mm insert. Why not drill a 5mm hole? We have found we get a tighter fit by drilling a 4mm hole then using a small round file we enlarge the hole just enough to get a tight fit.
Using Rivnuts requires special tools and training. It is a "one shot" task as the Rivnut cannot be too tight (will distort the insert), and it cannot be too loose, (if too loose it will spin in the frame), and it must be perfectly aligned with the existing inserts. There no substitutes for the use of Rivnuts and everyone who builds lectric bikes has to learn how to use them correctly.
Use of Adaptors
Final words on the battery
Use of Adaptors
For the most part we make our own adaptors. We make adaptors from a variety of material for a custom fit on every bike. However, we will use the Wolf Tooth E-Rad system pictured above when it the best option. What this small rail accomplishes is it can utilize the existing water bottle inserts to attach the rail and then the battery can be repositioned. Adaptors like these allow the use of a downtube battery without have to drill the frame.
Battery Weight
Final words on the battery
Final words on the battery
The weight of the battery is paramount when installing on a bike frame. If the weight of the battery exceeds the ability of the attachment points to hold the battery in a firm position then it should replaced with a lighter battery. To us, safety and functionality is more important than range.
If range is essential to a rider, yet we cannot use a large battery on the downtube, then we discuss the rear rack option. A stable rear rack can safely accommodate any large battery within reason.
Final words on the battery
Final words on the battery
Final words on the battery
The three most difficult steps of any electric bike conversion: Battery placement, setting the motor, and establishing a correct chainline. Batteries can be heavy and it is our job to insure the battery be attached to the bike in such manner it will never come loose, never damage the frame, and allow for simple removal for charging.
Every bike we convert to electric we encourage the buyer to bring the bike in after 6 months for inspection. We examine the battery base plate, tension the screws, look for any parts showing rust, and closely examine the battery base plate to insure it is in perfect condition. If we see evidence of any cracking we replace the baseplate and install new flexible washers.
Motor installation
Bafang mid drive installation
Bafang mid drive installation
Bafang mid drive installation
Here you can see the crankset has been removed. It looks very simple to slide the motor in and tighten it up and off you go. There are many things that can make this job very difficult. First, the bottom bracket might have an occlusion that will block the axle of the motor from being inserted. Any occlusions need to be removed by hand filing, or the use of a Dremel. Second, cables might need to be rerouted. The shift cable and the brake cable (or hydraulic hose) must not be impeded by the motor. Many bikes have internal routing of the cables and lines and these exit right into the path of the motor. The motor cannot be allowed to sit on these cables and lines therefore we will reroute them. Rerouting shift cable requires experience, if done incorrectly the shifting of the bike will be compromised.
Bottom Bracket Size
Bafang mid drive installation
Bafang mid drive installation
It is incorrect that there certain bottom bracket sizes that prevent the use of the Bafang mid drive motor. There is no bottom bracket size that we cannot make an adapter. We do not sell our adaptors and are solely for use of our clients. It has taken years to reach the point where we can install a Bafang on any bike with any bottom bracket standard. We have invested thousands in lathes, mills, cutting and drilling tools.
There a few adaptors available on the internet but the problem is they are for the most common sized bottom bracket shell. There are 22 different bottom bracket sizes. We are the only manufacturers that can accommodate any bottom bracket standard through our use of custom adaptors.
The fixing plate
Bafang mid drive installation
The fixing plate
Once the motor is in place we install the fixing plate. The fixing plate has raised ribs on one side. These ribs face the bb shell. Two M6 bolts are installed but not tightened. This fixing plate has to be tightened to the degree those small ribs are forced into the bottom bracket shell. Sounds easy? No...
Every week people call us about their motors coming loose...not our motors, but those built by themselves or other builders. When we install a motor it has a lifetime guarantee of never coming loose. We use different techniques for each type of frame material. For example, if the frame is of steel or titanium we use a different method than we use on a softer material such as aluminum or carbon.
M33 nut
Working with the powerful Bafang motor
The fixing plate
This is a M33 locknut and locking cap. Some believe this M33 locknut and cap plus 60Nm of torque is all it takes to secure a motor to a frame. Sometimes that is the case but other times not even close. There are many factors involved in securing a Bafang motor to a bicycle frame in a way that it will not come loose for the life of the bike or motor. For example, frame material, location of the bottom bracket shell, circumance and length of the shell, the facing of the shell (is it perpendicular to the motor mousing), obstructions on the downtube where motor rests, all of these play a role in proper motor installation. The black locking cap is more for aesthetics than locking. If the motor is not correctly set, the cap will have no effect. We do not use Loctight on the locking cap as it is more decorative than functional.
Working with the powerful Bafang motor
Working with the powerful Bafang motor
Working with the powerful Bafang motor
Some say, "Bafang motors come loose...avoid them." Time for some clarification. First, a poorly installed Bafang mid drive will work itself loose. A properly install Bafang mid drive will never come loose. These motors are the most powerful motors of their class. It is no secret ( well...may it is a secret) that some bike manufacturers reduce the amps of their motor in order to keep them in place. Bikes are commonly sold with 250 and 500 watt motors that behave in a civilized fashion but the problem is that there is not enough power for the hills, large riders, or heavy loads.
What good is an electric motor if it can only be ridden on flat surfaces? There are thousands of miles of beautiful hills to enjoy so have a motor that can exploit every foot of available terrain.
Install the motor right the first time
Working with the powerful Bafang motor
Working with the powerful Bafang motor
We have a number of methods we use to secure a motor and they all depend on the type of bike, frame material, size of the motor, geometry of the bike, and type of use. There is no "one size fits all." It was an imperative for us to develop a dependable method of securing the motor as we need to warrant the motor against movement for the life of the bike. By developing these methods we are able to make use of the full 750 watts, or 1000 watts of the Bafang mid drive. However, there are some instances where we may be working w/exotic frame material or custom frame geometry that will require de-tuning of the motor in order to decrease the torque.
Out of all the motors we have installed, they are still exactly where we placed them.
Cable management
Lots of cables...
Theory of usability
Lots of cables...
Cable management is an art. In order to make an electric bike work requires cables and in these cables are very small wires. We do not have the luxury of cutting the cables and soldering each wire together in order to get a custom fit. Therefore we take the existing cables and figure out the most esthetically pleasing, yet functional method of routing. We do not...just take cables and wind them around the seat tube (as we often see on bikes brought to us).
When we cable a bike we first search for the natural lines of the bike and then we follow the path that the designers of the frame envisioned for their shift and brake cables. We often marry our cables to the existing cables of the bike. When we are finished the cables look as if they were integral to the bike.
Yes, it matters
Theory of usability
Lots of cables...
This is a bike similar to the bike I raced. After every race I would take the bike apart all the way to the bare frame and clean every part in preparation for the next race. From race to race it looked like my bike was just off the showroom floor. The one thing that seems to be common among all of us cyclists is that style matters. What our bike looks like is a reflection of who we are as riders. Sometimes a bike comes into our shop covered with stickers of political affiliation, habits and hobbies and they all tell us something about the rider. A glance at a bike can tell you a lot about the rider.
Because esthetics matter to all of us, we are diligent to cable each bike in such a manner it adds to the look of the bike, not detract from it. In addition, because the frame of a bike will vary from one to the other, there is no set pattern. We have to figure it out and sometimes it can take hours to get it right.
Theory of usability
Theory of usability
Final polish - Spit shine
"Embellishments can only produce surface delight; deep delight can only be achieved in functional, reliable, and usable interfaces."
Aarron Walter
That is the bottom line...an electric bike must be evaluated on usability...it has to work and it has to work well. It does not matter how well the cabling is done, or the power of the motor or the number of watts or amps...or even what one paid for the bike, what matters is how well the finished product performs. Everything else is meaningless when compared to function.
There is nothing more disappointing than an electric bike than cannot climb hills, or battery range that is insufficient, or support after the bike is purchased is non existent. I am often ask why I only build with the Bafang mid drive motor and I always say "show me a better motor and I will switch." Why do I spend so much time cabling a bike...because it matters. But...all of this is secondary to the actual functioning of the bike.
Final polish - Spit shine
Final polish - Spit shine
Final polish - Spit shine
Many of us we remember the term "spit shine." It is a familiar term drilled into new recruits in the Armed Forces. The Drill Sergeants demanded the boots of all his troops shine to the degree he could see his reflection. How to get leather boots to shine like polished marble? By spitting on a cloth and slowing working the polish into the leather. Many a night I would see young recruits polishing their boots into the night by the glow of a small lamp.
While we do not use the exact method (thank goodness) we do take the time for one last cleaning before we return the bike to the owner. For this cleaning we use two products. First, a gentle solvent. This takes most marks off the frame of the bike. Then we follow with a stronger solvent in order to remove the more difficult marks.
In the end...your bike looks like the day you purchased it...almost.
Test ride
Final polish - Spit shine
Final thoughts
We test ride all of our bikes that we convert to electric. This is very important. The other day one of our mechanics took a Surly Big Dummy for a test ride. Upon returning he said, "Bike rides great but something is wrong with the steering. We put the bike on the stand, removed the front fork and there it was...a broken headset bearing.
We have converted close to 2000 bikes to electric and have test ridden each one, with one exception. We converted a two wheeled recumbent to electric only to find no one in the shop knew how to ride that type of bike. I tried several times to balance the bike long enough to pick up my feet and start pedaling. I finally gave up half out of fear of damaging the bike and half out of fear of damaging myself.
When the owner arrived, I told them it had not been test ridden because none of us knew how to ride the bike. He chuckled and said, "Nothing to it," and off he went.
Final thoughts
Final polish - Spit shine
Final thoughts
To date, we have converted close to 2000 bikes to electric. Last year we saw one bike that could not be converted due to the design of the frame. This year we converted that same bike to electric without any difficulties. What made that possible is the fact that we are better today than we were in the past at problem solving, machining parts, and creating innovative techniques of installation. We are the only company who provides a lifetime warranty on the motor staying exactly where we placed it without coming loose. We have built special tools and methods of installment to insure our work is second to none. As my mother used to say, "It isn't bragging if it's true."
The Conversion of a standard bike to an electric bike
Thank you for reading this page
While updating this page I thought that I never dreamed we would have converted nearly 2000 bikes to electric in such a short period of time. This year (2021) we quadrupled our shop space, installed 4 Park Tool heavy duty electric bike lifts, have a full complement of speciality tools, increased our machine shop equipment, and have been invited by other bike manufacturers to advise on electric bikes. It is no secret, I am not a young man. But, with many years comes experience and not just with bikes, but with people. I believe there is good in all people. I have found, given time, that good will come out of us all. When it does, a relationship is formed. That is why I never use the word "customer." I only have "clients." I have had over 2,000 clients and all of them are people I am glad met and hope to meet again.
Alvin Carpenter, PhD