Electric bikes can be spendy. It must cost less to build your own, right?
The cost to convert a bike to electric can cost as much as an entry-level eBike (or more).
A DIY electric bike kit with a battery starts at around $550, with prices for some electric bike kits approaching $1,000.
If you see a kit for less, check to see if it comes with a battery. The battery pack is often one of the most expensive electric bike components, and many inexpensive kits don’t include one.
An electric bike conversion probably won’t look as sleek as the KBO Hurricane e-road bike pictured in the intro, but sleek isn’t always the point with DIY projects.
It also won’t necessarily be any more affordable. You can pick up a Hurricane for well under $1,000 when it’s on sale. Or, if you’re shopping on a budget, the Macwheel Macmission 100 comes in at under $700 when they’re running a deal. And it comes with dual disc brakes.
What you will get with a build-it-yourself eBike is a bike built to your specifications. You choose your own electric bike components, such as wheel size, chainring size, and battery size. You also choose which type of conventional bike to convert to electric, be it a mountain bike, gravel bike, or road bike.
It’s even possible that your current bike frame could make a good donor bike for the project. An electric bike wheel conversion can be a cost-effective way to press that lonely bike sitting idle in the garage back into service.
The end product in the conversion process can depend on how handy you are. With a growing selection of electric bike conversion kits, you don’t need to be a bike mechanic or use a bike shop to build an electric bicycle.
DIY eBike Conversions versus eBike Conversion Kits
Recently, I watched a YouTube video in which someone built their own eBike for under $150 using used parts from rental eBikes. Pretty fun project, even if not the most beautiful bike in the world.
Or, if you have a box full of electric motors sitting around and a healthy helping of shade-tree engineering prowess, you might be able to build this bike on the cheap (about $200).
Many backyard builders choose off-the-shelf kits instead, which can drive up your cost to convert a bike to electric.
Kits are convenient. Electric bike conversion kits solve the problem of having to find all the parts and fiddly bits you’ll need. But the cost of a kit (plus a regular bike to convert) often starts to compete with the cost of an entry-level electric bike.
The upside is that you’ll often end up with a more powerful bike compared to entry-level eBikes, and you’ll roll away with a sense of accomplishment.
This, of course, assumes your DIY bike works at all when it’s complete. Fingers crossed.
Also, budget some time for troubleshooting. Odds are fair that at least one part of the conversion process will go sideways.
And if time is money for in your world, the time spent on the project belongs somewhere in the overall cost breakdown. For example, if you could earn $40 per hour doing something else, then spending six hours converting a regular bike to electric adds $240 to the project cost.
If you’re like me, though, these types of projects are a labor of love, perhaps combined with the sticktoitiveness that accompanies a matter of principle.
Front-Hub Versus Rear-Hub or Mid-Drive Electric Bike Conversions
Life is made of choices, and electric bike conversions can be accomplished in several ways. We’ll bypass some of the less traditional methods because most of us aren’t mechanical engineers.
Instead, let’s examine the three most common ways to convert a bike to electric as well as the cost for each.
- Front hub conversions: The motor is in the front wheel.
- Rear-hub conversions: The motor is in the rear wheel.
- Mid-drive conversions: The motor is attached to the front drivetrain.
Generally speaking, you only need three main components for basic functionality:
Technically, you can build an electric bike without much more, similar to how you can connect a small electric motor to a 9-volt battery and watch it whirr to life instantly.
If you want to control the speed (always a good idea), you’ll need some additional parts, such as a throttle or control panel, to choose an assist level. Kits usually come with brake levers and cables that cut power to the motor when braking.
In most cases, you’ll also get a sensor with kits that triggers the pedal assist. Expect a cadence sensor with more affordable kits, which “watches” to see if you’re pedaling and then sends a signal to give you a helping hand. Pricier eBikes often come equipped with torque sensors that sense pedaling effort rather than a binary “yes pedaling” or “no, not pedaling” seen with most cadence sensors.
Expect cadence sensors rather than torque sensors with most eBike conversion kits. However, mid-drive kits may include a torque sensor. Pricier kits can come with shift sensors as well that cut power to the motor momentarily while shifting.
Front-Hub eBike Conversion Kits
You’ll often find the lowest prices on front-hub conversion kits. Remember, though, that many of the kits you find on Amazon or eBay don’t come with a battery. Budget another $250 to $300 for a battery if the kit you’re considering lacks a power source.
Front-Hub Electric Bike Kit
To prevent axle rotation, you’ll also need a torque arm, but these are inexpensive. You can pick one up on Amazon for about $10 to $15.
Bafang is among the best-known eBike motor manufacturers, while Voilamart is well known for low-cost electric bike conversion kits. It’s also worth noting that the Bafang kit uses a 500-watt (864-watt peak) motor, whereas the Violamart uses a 1,000-watt motor limited to 750 watts by the controller.
In total, the cost to convert a bike to electric with a front-hub motor starts from just under $600 to about $800.
The choice to convert a bike to electric should consider more than just cost, however. Give some thought to the pros and cons of each option.
Front-hub motors bring the benefit of all-wheel drive, but only when pedaling. When you’re not pedaling, the front wheel does all the work (in addition to steering).
Front-wheel-drive setups work great for cars with the engine over the drive axle. But for some electric bikes, a front-hub motor can be a squirrelly setup, particularly on gravel or slippery surfaces. Weight distribution can contribute to unpredictable handling as well when you convert a bike to an electric front-hub setup.
Front-hub is usually a cheaper way to go compared to rear-hub or mid-drive motors, but it’s not for everyone.
Rear-Hub eBike Conversion Kits
Rear-hub eBike conversions usually fall in the middle in regard to price. However, you can expect handling to be closer to what you’re accustomed to with a standard bike. But easier.
With rear-hub motors, the motor powers the rear wheel but operates independently of the drivetrain. This setup is how most electric bikes come from the factory because it combines affordability with predictable handling. With weight distribution centered close to the drive axle, the bike has better traction compared to front-hub electric bike wheel conversions.
Toss reliability in there as well. Because a rear motor operates separately from the drivetrain, the chain sees less stress, thereby reducing the chance you’ll have to do the walk of shame with your creation, its broken chain sparking against the pavement all the way home.
Here are some price ranges to compare:
Rear-Hub Electric Bike Kit
Rear-hub brings some other advantages as well. You’ll have more gearing options with a rear motor compared to mid-drive eBikes, which use a single chainring in the front. With rear-hub and front-hub eBikes, you can choose a bike with 3 gears at the crank. While adding some extra weight, the additional gear options can be helpful if you have to pedal home.
There are some good reasons why most factory-made electric bikes use a rear hub drive system. Control and reliability top the list.
The rider’s weight over the rear wheel helps the bike put down power in a controlled way, an advantage over a front-hub motor at times. In addition, rear-hub motors can make the bike more reliable overall because they don’t put a strain on the drivetrain like a mid-drive motor.
Mid-Drive eBike Conversion Kits
Like front-hub and rear-hub motors, mid-drive systems have their pros and cons. You’ll get a lower center of gravity for a stable ride and more efficient power delivery. But you may also see more wear on the drivetrain because the motor is integrated with the drivetrain. Dropped chains and chain breaks are more likely.
With a mid-drive motor conversion kit, the motor replaces the stock bottom bracket.
Here’s an idea of what to expect on average cost:
Rear-Hub Electric Bike Kit
One benefit of a mid-drive motor becomes evident when you need to remove a wheel.
Because the motor is mounted mid-ship, removing the wheel to fix a flat or install new tires is a simple process, just as it is with a normal bike. That’s not the case with front-hub or rear-hub eBikes, both of which add some complexity to removing the drive wheel.
Are eBike Conversions Safe?
A full kit usually comes with safety components such as brake levers with cables to cut power to the motor when you brake.
Some of the DIY bikes you’ll see on YouTube may not have that feature. Without this component, braking can take longer because the bike could be braking against a still-running motor.
Handling for rear-hub and mid-drive electric bikes is generally predictable. But front-hub electric bikes can be tricky for some riders, especially if the front wheel becomes unweighted temporarily, like on a grassy or dirt hill.
Here’s the likely breakdown regarding safety for the various ways of acquiring an eBike:
- Factory-made electric bike: Safest
- Electric bike kit: Kit choice and assembly quality (read: you) may affect safety
- DIY built from miscellaneous parts: Safe? Who needs safe?
Electric bike fires can also be a concern. Although the risk is not limited to converted eBikes, there could be a larger risk if using a mix of off-the-shelf parts or rough-and-ready electrical connections.
Is the Cost to Convert a Bike to Electric Worth It?
You can find factory-made electric bikes for not much more than the cost of a kit (plus the donor bike you’ll convert). For most people, it could be tough to make a math case supporting the cost savings of converting a bike to electric, especially with a lower-end electric conversion kit.
However, if you’re willing to invest in a nicer electric conversion kit or components, a converted eBike can offer better power performance than many factory-made electric bikes and for less money than typical high-end eBikes.
But electric bike choices don’t always revolve around money.
Sometimes, it’s just about the spirit of adventure. I’ve seen some pretty fast DIY builds, fast enough to make me start pricing out the parts for a build with a powerful motor.
Frequently Asked Questions
Are eBike conversions legal?
Check with your state or municipality to be sure your electric conversion kit is street legal. Each state has its own rules regarding the different classes of eBikes. Some cities place restrictions as well, often basing legal limits on power output or faster speeds.
Electric bike insurance for your converted eBike can also be a consideration. Even if you aren’t concerned about the value of the bike, liability can be a risk with potentially expensive consequences if you aren’t covered.
Do electric bike conversion kits come with a battery?
You can buy electric bike conversion kits with a battery, but many kits do not include a battery. Expect to pay about $250 and up for a battery if your kit does not include one.
You’ll also need to research ways to mount the battery securely. In some cases, you can mount the battery to the downtube on your bike. Other solutions include a rear-rack battery or a battery stored in a nylon pouch.