Resurrection

A Novel Approach To E-Bike Conversion

E-bike motor conversions have gained considerable traction among cycling enthusiasts and DIY advocates over the years. Long before electric bikes became so popular, the shade tree diyer's were hard at work installing and configuring electric drives on all manner of bikes and trikes. The conventional process involves modifying an existing bike, and installing an electric drive system, which come in any number of configurations - hub, mid drive, friction, direct chain, and more. The decision to undertake such a conversion is often driven by a variety of factors, including performance improvement, customization, and a desire for an enhanced riding experience.

While a common chassis type for a conversion is a conventional bike, trike or recumbent, there is another candidate that is often overlooked - a production level hub motored e-bike. While there are literally hundreds of millions of these e-bikes being ridden around the world today, there are also a large number that may either have a fatal issue involving a drive system component caused by lack of parts availability or obsolescence, or it is underpowered and underperforming for the intended purpose. Unfortunately, lower costs of production level e-bikes, mainly from China, while driving demand for the sport, has also created incompatibility and a lack of standards of many drive components among the large number of manufacturers, who are all competing for success in the market. Many of these e-bikes served their intended purpose, mainly as a low cost introduction to the sport.

So what happens to all of these e-bikes that have developed one of these problems, possibly preventing their continued usage? And let's say a person comes across a good deal on an e-bike with an issue, or has an unused one taking up space in the garage, what should that person do with it? Junk it? Give it away? Recycle it? How in the heck do you do that? All of this is a quiet dilemma with e-bike adoption, and has yet to be addressed fully by the industry or governments. Given the amount of potentially toxic materials found in a modern e-bike, along with the large amount of valuable metals, recycling is an option, at least in the future. For now though, maybe it's time to look at renewing that old ride with an upgrade.

Enter The Mid Drive Conversion

As we have discussed elsewhere on this site, mid drive motors are recognized for their superior weight distribution, which significantly contributes to balanced handling and maneuverability. Unlike hub motors, which are typically situated at the front or rear wheel, mid drive motors are positioned at the bike’s center, near the bottom bracket. This placement optimizes the bike’s center of gravity, leading to an efficient and responsive ride. Furthermore, mid-drive systems often provide improved climbing ability, enabling cyclists to tackle steep inclines with greater ease and efficiency. By leveraging the bike's gearing system, these motors can also deliver higher torque output, making them suitable for off-road adventures and varied terrains.

Beyond performance enhancements, this trend in motor conversion reflects a broader movement within the cycling community towards DIY modifications. Riders are increasingly engaging with their e-bikes on a mechanical level, customizing their rides to better meet their preferences and requirements. This hands-on approach not only fosters a deeper appreciation for e-bike technology but also cultivates a sense of community among cycling enthusiasts committed to personalizing their experiences.

The conversion process from a hub motor to a mid-drive motor typically involves several steps, including the removal of the existing hub drive assembly and the installation of a replacement wheel and compatible mid-drive components. Depending on the specific model of the donor e-bike and the mid-drive motor selected, this process may require additional modifications or component upgrades. As such, it is essential for individuals considering this conversion to conduct thorough analysis and research to ensure compatibility between existing parts and new components.

In conducting research prior to a conversion process, several items need to be looked at:

1) Mid Drive Compatibility - Does the bike or trike chassis have a conventional bottom bracket? If the intended builder does not understand this part of the anatomy of a bike frame, then a bike shop can certainly help with identification. Basically, this is the part of the frame where the pedals and bottom bracket assembly mounts into the frame. The most common type of bottom bracket is what is termed a 68mm BB width with English threads.

2) Chassis Condition - What is the condition of the wheels, brakes, and frameset? Taking a good look at what you will be mounting a new drive system on is paramount at this point. Brakes can be upgraded easily enough, as can the gear mechanism if equipped. It's the overall condition of the complete chassis that has to be looked at. If the number of components that need to be replaced becomes a big cost and time effort, then it may be time to consider another pathway. I liken this to having an automobile that you really like. It has been a steady faithful ride all these years, but it's not worth anything to anyone else but you. The motor or transmission goes out suddenly. Should you put in a new one, or not? This is not all that much different of a scenario. It's a combination of a personal enjoyment of the vehicle and the desire to continue to use it. But there is also that practical side - how much will it cost to bring the whole vehicle back into condition? If you are one of those rare types and maintain their vehicle to the letter, then I applaud that. If you are like many of us, things start piling up and really need to be attended to along with that new motor or tranny.

3) Battery - One of the components that may or may not be useable with a mid drive conversion is the battery pack. What is the condition of the battery? Has it reached its useful charge cycle life? Has it been maintained properly? Does it have the right voltage and capacity to match your intended future usage? Can it be rebuilt? (Yes most of the time) Many production e-bikes have the battery pack built into the frameset which makes a clean look. Others will have the battery attached on the front downtube or in a rack on the rear of the bike. The use of the battery, if in proper configuration and condition, could save a considerable amount of money in doing a conversion.

The voltage of the battery must match the specifications required by the new mid-drive motor. Typically, e-bike motors operate on battery voltages such as 36V or 48V, with the newest models such as the ToSeven DM Series offering 52V or even 60V nominal voltage. Therefore, it is essential to check the voltage rating of the current battery to ensure it aligns with the new motor's requirements. ToSeven has an advantage here in that the system is easily adjusted for various battery voltages right through its display interface. This is a crucial part of the conversion process. If the voltage is incompatible, the system might not function correctly, or worse, it could lead to damage to both the motor controller and the battery.

Another crucial factor to consider is the battery's capacity, measured in amp-hours (Ah). A hub motor battery might have a capacity that serves well for hub motor operations but may not provide sufficient power for a mid-drive motor, especially under heavy load conditions. It is advisable to calculate the expected performance demands of the mid-drive motor based on factors such as terrain and rider weight. This ensures that the battery capacity can support the required power output and duration of ride. If the battery case is in good shape, then the pack can often be rebuilt to the latest specifications, often with higher capacity than when it was new. Contact us for sources for rebuilding services.

Additionally, check the connector types between the battery and the mid-drive motor. Different systems may utilize varying connector styles, so it is vital to determine if adaptors are needed or if new connectors should be installed to facilitate compatibility. If reusing the old battery proves impractical, many options are available for sourcing a suitable replacement, given the array of e-bike battery models currently on the market.

4) DIY Capability - An e-bike conversion of any form is a sizeable but manageable proposition for the vast majority of people out there. An understanding of the process can be developed by using YouTube along with the host of forums and blogs out there. Quality drive systems such as the ToSeven DM series are available in a variety of configurations and sizes.Tools are readily available, especially specialty tools for working on such areas as the bottom bracket. For the parts of the job you don't want to do yourself, electric friendly bike shops are always a source. Keep in mind that the vast majority of components on a decent quality e-bike are related to conventional bikes.

5) O.L.D. - Production e-bikes may have a different width of the front or rear wheel in order to accomodate the hub motor. This is referred as the O.L.D. or Over Locknut Distance. In doing a conversion to a mid drive, replacement of the hub motored wheel assembly with a conventional bike wheel will be necessary. Proper width of the new hub will be crucial. This is where that electric friendly bike shop comes into play. Any good shop will have access to wheel building services that can put together a wheel set for you. The easiest way to do this is to take the hub motored wheel into the shop and ask if they can match the assembly with what you have. That way, the gear cluster will swap out, the hub will slip right in, the tire will fit right, and the axle will lock the wheel in place properly.

6) Cables and Controls - Cables will obviously need to be long enough to be able to tie all components together. Luckily, most quality mid drive conversion systems will have extension cables available for such items as the speed sensor. Also, controls, such as a throttle, display and brake inhibitors all need to be located properly. Most e-bikes use conventional bars (an exception might be a folding e-bike), so fitment of controls is usually pretty straightforward. The modern Recumbent Tadpole style trike is always a good challenge for control fitment. Luckily, there is a huge number of bents that have been converted, so this is rarely an issue.

So as you can see just from this basic list, there are a number of steps needed to consider in looking at this option. I will end with this: That first post-conversion ride is like nothing else and needs to be experienced to fully understand.

Feel free to email us for any input or questions you have.