What You Should Know About Electric Bike Conversion Kits

Do you want to convert your bike to electric but need to know where to begin? In this Electric bike conversion kit tutorial, I will examine the many options for adding electric assistance to your bicycle.

Converting a bicycle to an electric assist may be an advantageous experience if you are ready to take the risk. Also, you can save a lot of money compared to buying a factory-made e-bike.

DIY Electric Bikes vs. Factory Electric Bikes

A basic entry-level mid-drive electric bike will save around $2000. I spent less than $1160 to make the brand-new DIY mid-drive e-bike shown below (including the cost of the new donor bike).

The donor bike for this construction was a Decathlon BTWIN Riverside 900 with a Tongsheng TSDZ2 mid-drive motor and a 36v 13ah battery.

As you can see, changing a nice spec new bike to electric assist can result in significant savings. If you convert an existing bicycle, your savings will be considerably more significant.

Assume you have an old Trek or Cannondale mountain bike in your storage. A good mid-drive conversion kit with a battery would typically cost approximately $780. This is a significant saving compared to purchasing a factory-built mid-drive electric bike.

Decathlon E-Stilus

Converting a bike to electric is only for some. If you’re not mechanically inclined, I’d prefer buying a factory-produced electric bike or finding someone to install the kit.

Remember that a retrofit electric bike conversion motor may not be as long-lasting as a Bosch or Shimano stepping motor used on factory-produced electric bikes.

To select the best engine for your purposes, you must first determine your intended usage.

If you live in a relatively level location with only moderate inclines, a modest geared hub motor might suffice, but if you live in an area with relentless high hills, a mid-drive would be more appropriate.

Finally, your selection will be impacted by your demands. Both motors have a place on e-bikes, but remember that mid-drives are significantly more energy efficient than tiny hub motors.

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Direct drive hub motors

The direct drive hub motor is the most basic method of electric bike propulsion: The outer shell of the hub is an integral element of the motor and is fastened with a large ring of strong magnets.

When the motor is turned on, it drives the wheel directly (thus the name). Said, the wheel is a motor with the shaft fixed such that the body of the motor (the outer hub shell, and therefore your wheel) rotates instead of the shaft.

It is a simple design, but it has a cost: the motor must be relatively large and hefty to create enough power. A smaller motor rotating slowly would not provide adequate torque, and because the speed at which you want your wheel to turn is quite sluggish, the motor must be as large as feasible to produce torque at low speeds.

On the bright side, direct-drive hub motors are inexpensive and dependable and can handle a lot of power. A large hub motor may be the way to go if you want a high-performance electric bike on a budget.

Geared Hub Motor

geared hub motor.


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Small geared hub motors are far more efficient than direct drive motors. A planetary gear reduction arrangement links the motor casing to the stator. The motor within spins many times faster for each turn of the casing. This permits the motor to operate at greater (and more efficient) speeds while yet allowing the wheel to spin at a slower driving speed.

Another significant advantage of a geared hub motor is that there is virtually no pedaling resistance if the engine is turned off or runs out of juice – you can ride as on a regular bicycle.

Geared motors are often maintenance-free, but if you do a lot of hill climbing, the nylon planetary gears will likely wear down over time. Fortunately, they are inexpensive and straightforward to repair.

Rear Hub Motor vs. Front Hub Motor

Kit for converting a front-wheel electric bike

Installing a front hub motor vs. a rear hub motor has several advantages and disadvantages. Front hub motors are typically easier to install for electric wheels. The primary reason is that you won’t have to change gear cassettes or freewheels.

A compact, geared hub motor would be ideal for front-wheel electric conversion. This is because they are small, lightweight, and create adequate torque.

There are even larger direct-drive front-wheel electric bike systems available. They are often less expensive and more powerful, but their larger size might make them easier to install onto motorcycles with disc brakes. They are also heavier and less efficient.

Another advantage of a front hub motor is that when you use the pedal assist, the bike is propelled by both wheels. While the electronic front wheel assists you, you put force via the back wheel by pedaling.

Electric front wheels are not ideal for off-road riding since the powered wheel might spin on uneven terrain, especially when ascending steep slopes.

Conversion Kit for Rear Wheel Electric Bikes

A rear-wheel electric hub motor is typically preferable when adding electric aid to a bicycle with a conversion kit. Changing the rear wheel requires more effort, notably removing the gear cassette (or freewheel), which requires a unique tool.

In riding, the motor pushes you rather than pulls you (as with a front motor). Generally, a smaller, geared rear hub motor will be much more discrete.

Another advantage of rear hub motors is that they perform much better on rocky terrain. Because the rider’s weight is centered on the back wheel, wheel spin is significantly less of an issue.

The only significant disadvantage of this design is that changing an inner tube during a puncture takes time. I recommend a robust puncture-resistant tire, such as a Schwalbe Marathon Plus, to drastically limit this danger.

Motor with Mid-Drive

Mid-drive motors are the preferred driving mechanism of higher-priced e-bikes. These motors are the most efficient and deliver far more torque than hub motors.

Fitting this type of motor might be difficult for inexperienced users since the bicycle’s bottom bracket must be removed to assist installation. Once this task is completed, the remainder is quite simple. Most mid-drive kits are only compatible with conventional threaded bottom bracket shells that are 68 mm-73 mm wide and around 33.5mm in diameter.

When properly fitted, a mid-drive system will give your bike the appearance and feel of a more expensive e-bike.

The only disadvantages of mid-drive motors are more excellent pedaling resistance when the motor is turned off and the need for regular maintenance (such as tightening the motor). You will also have only one chainring on the front.

Hub motor vs. mid-drive motor

Considering everything, it all comes down to your budget and the riding you want to conduct.

Small hub motors are typically less troublesome than mid-drives in the long run. Another thing to think about is pedaling resistance. The mid-drive and direct-drive hub motors generate substantial resistance with the motor turned off.

Mid-drives outperform geared hub motors for hill climbing; a 250w Bafang BBS01B produces roughly 100% greater torque than a geared hub motor comparable.

Hub motor kits have a more ‘DIY’ appearance, with an external controller (typically in a frame bag), an external pedal assist sensor, and much cabling to clean up. Mid-drive motors produce a cleaner and neater-looking result.

Choosing the Best Battery

The battery you choose will affect the range of your electric bike.

First and foremost, you will want a battery with the appropriate voltage. Most kits are 36v or 48v; 48v kits usually use 52v batteries, although this might impact dependability in some circumstances. Some specific motor controllers will accept a 36v or 48v battery, but you should double-check this before purchasing.

The Ah (amp hour) specification measures battery capacity. In other words, it represents how much energy the battery can hold. A 36v 13ah battery (36v x 13ah) has a total energy capacity of 468Wh (watt hours) and a range of roughly 23 miles utilizing a constant 20Wh per mile. This value might be significantly higher or lower depending on the power level employed, rider weight, terrain type (flat or hilly), and wind direction.

Another factor to consider is the size and design of the frame into which the battery will be installed. Regular hybrid or hardtail mountain bikes with 18′′ frames and higher usually have plenty of room, but with 16′′ frames, things may get a lot tighter.

Mounting a battery in the frame of a full-suspension mountain bike can be nearly tricky (depending on the bike). Ladies’ frames and step-through bikes are typically better suited to a battery on the back rack.

Before choosing a battery, you should collect the dimensions of your frame triangle. It is also worth mentioning that specific battery packs do not match appropriately with the frame’s bottle-holding threads. In this instance, you may need to drill and riv-nut an additional hole or two.


If you need some assistance with hills but prefer to ride under your power for most of the time, a compact geared hub motor is the way to go. A mid-drive will be a better alternative if you want a bike that can easily tackle particularly steep hills. Converting a bike to an electric one may be both difficult and gratifying.

Most individuals do not convert a bike because it is the “easy option.” But they’re seeking something distinctively their own. Alternatively, they may have an old bike with emotional significance. If you’re up for the task, go for it! However, keep in mind to verify the e-bike rules in your place of residence.

Thank you for reading this post, and we hope you found our electric bike conversion kit instructions helpful. Please comment below if you want more assistance or guidance in selecting a conversion kit.

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