The 13 Best Electric Bike Kits in 2025 – Reviewed & Buying Guide

The electric bike kits are the best solution for those who want to transform their bicycle into a pedal-assisted model; they are also useful for those who already own an electric bike and need to repair it or improve its performance.

For those who do not have a big budget to invest in an electric model, the conversion kit represents a cheaper solution to obtain the same advantage, therefore to pedal with less effort.

The most important element of the kit is the engine, which can be positioned in the central part of the frame, on the front or on the rear; usually there is no battery and charger, which must be purchased separately.

Right here are the Best Electric Bike Kits listed below.

Decisive Factors for The Choice of The Electric Bike Kits

Electric bicycle side structure

On the net as elsewhere, the term electric bicycle and its English version e-bike are used indiscriminately to indicate both self-operating and pedal-assisted electric bicycles (the latter also called pedelec, pipa or pas).

In reality it is good to specify that the European directive 2002/24 / CE defines which electric bicycles can be defined as a pedal-assisted. The characteristics are as follows:

Have a Nominal Power Lower than 250 W

Activate yourself and only in conjunction with the ride. With the pedals stopped, the engine must also stop automatically

Deliver maximum power at low speeds and then gradually decrease, until it stops at the speed of 25 km / h

We with the term electric bicycle will always refer to pedal-assisted bicycles. Despite its ambiguity, we have preferred to use this term because it is more immediate and easier to understand.

However, we always recommend paying close attention to the technical specifications before purchasing an electric bicycle, in order to avoid bad surprises or risk incurring fines and penalties.

Where Can the Electric Bicycle Circulate?

As we said, electric bicycles are divided between pedal-assisted and autonomously operated bikes. Electric bicycles with pedal assistance can circulate on the road like traditional bikes and therefore are not subject to particular limitations. To drive autonomous electric bikes, on the other hand, you must have an AM license.

1. Engine

The first factor to consider when choosing an electric bicycle is definitely the engine, because it is undoubtedly the central component of this type of product.

Before seeing in detail the characteristics on the basis of which we suggest you evaluate the motor of an electric bicycle, we want to make a small clarification, explaining how the belonging of a product to the family of electric bicycles depends on the type of motor.

We now see in the next sections the specific characteristics of the engine that influence its performance, and that we suggest evaluating in the choice of the electric bicycle.

Electric Bicycle Power

We have seen how, due to the regulations listed above, it is not possible for an electric bicycle to mount a motor with a rated power greater than 250 W, however, it is also rare to find motors with a lower power.

The power indication is also associated with the battery voltage, so the data that we will find on the technical datasheet of our bicycle will be for example 250W / 24V, or 250W / 36V.

For the purpose of the power supplied by the motor, the voltage does not change anything, but it will be useful to keep this in mind when the battery needs to be replaced.

It should also be remembered that upon reaching the speed of 25 km / h the engine will stop: this does not mean that it will no longer be possible to continue pedaling, but that the speed maintained will only be given by the strength of the legs, at least until you have returned below the 25 km / h limit.

Type of Engine

There are two types of bicycle engine:

1. Brushed: which are alternating current and are the most obsolete as they are heavier, bulkier and less efficient;
2. : which are direct current, lighter and more performing.

Position of The Engine

The engine position itself must also be taken into consideration. The engine can in fact be located on the hub (the center of the wheel where the spokes converge) of the front wheel, on the hub of the rear wheel, or in a central position, or on the pin where the pedals are inserted. electric bicycle see how the positioning of the engine affects the performance of the bicycle:

• Front Motor: the motor located on the front wheel hub is certainly the easiest to assemble because it does not get in the way of the chain and pedals. However, this positioning modifies the traction of the bicycle, which would naturally be rear, and can create an imbalance in the distribution of the weights and some difficulties in driving. For example in case of rain, on steep climbs or on dirt roads, the front wheel will risk losing grip, and being the driving one it could slip making the bicycle less stable;
• Rear Engine: with the rear engine there are no slipping problems, as the traction of the bicycle is not changed, but we would like to point out that due to its proximity to the gearbox gears such an engine could be more inconvenient to assemble. This is not only a problem for the manufacturer, but also for the cyclist himself, who in the event of having to replace the wheel in the event of a puncture should first disconnect the motor cable;
• Central Engine: it is the most practical solution, but also the most expensive. While the hub motors can also be mounted on standard bicycles (there are numerous conversion kits on the market), the central motor cannot be mounted later, therefore the frame itself must also have a specific structure to accommodate it, with very few exceptions. In our opinion this represents the best solution, because the engine positioned in this way does not interfere with the assembly or disassembly of the wheels and can be combined with both torsion sensors and pedaling sensors (which we will discuss later).

How the Electric Bicycle Works

As we explained in the previous paragraph, the engine can be mounted in different positions but the operation always remains the same. In pedal-assisted electric bicycles the engine starts when pressure is applied to the pedals.

In this way considerable speeds can be achieved even with minimal effort. Self-operating electric bicycles, on the other hand, work like a small motor: the motor can start running at any time regardless of the use of the pedals.

2. Battery

Closely connected to the engine is the battery. It determines the autonomy of the electric bicycle, i.e. the time and kilometers for which it will be possible to use it before having to recharge it. electric bicycle battery housing. In the list below we see what are the parameters on the basis of which the efficiency of a battery can be assessed :

1. Technology: batteries can be nickel-metal hydride (Ni-MH), lead gel or lithium. Without going into too much detail, the best are certainly lithium batteries, as they are the ones that guarantee the best weight/capacity ratio. This means that, if compared to lead or nickel batteries, lithium batteries will be the lightest with the same capacity. Furthermore, with the same autonomy, lithium batteries require a shorter charging time;
2. Capacity: the capacity of a battery indicates the amount of Watts it can deliver per hour (it is indicated in Watt-hours, Wh). The quantity of Wh therefore indicates how much energy the battery can supply to the bicycle’s engine. Clearly, the more assistance we will ask the engine, the less battery life will be. To calculate the capacity of a battery, just multiply the voltage (V) of the battery by the intensity of the current per hour (Ah), therefore a 36 V and 10 Ah battery will have a capacity of 360 Wh. Below 360 Wh we can speak of a low capacity battery, while above 450 Wh we already speak of high capacity batteries;
3. Autonomy: calculating the average autonomy of a battery is not easy, because many factors come into play, most of which do not depend on the technical characteristics of the bicycle (weight of the cyclist, the slope of the road, the type of terrain, level of assistance, speed). In addition, the battery itself will age over time, progressively reducing its performance, until it finishes its cycle around the third year. Furthermore, autonomy is linked to the capacity of the battery itself. In general it can be said that modern electric bicycles have a high autonomy if it is greater than 80 km, average if it is between 80 and 50 km, low if less than 50 km;
4. Position: finally also the position of the battery has its importance, as it affects the balance of the weights of the bicycle. The battery can in fact be positioned either on the luggage rack, or on the triangle of the frame. This second location is preferred, not only because it does not further unbalance the load of the bicycle on the rear wheel, but also because it allows you to free up the space of the luggage rack, on which instead it will be possible to mount a basket or a child seat.

How to Recharge the Electric Bike

Most models allow you to remove the battery to charge it more easily, in any case, there are some precautions to follow to avoid damaging the battery and ensure a long life:

• Do not charge the battery when it is still hot
• Keep the battery charged even when it reaches 100%
• Here are some tips to increase the battery life of the electric bicycle:

1. Use the maximum assistance level only when climbing
2. Start in a soft gear and then change when you have gained speed
3. Check the tire pressure frequently
4. Avoid carrying excessive weights

3. Pedaling Assistance

Unlike a moped, the engine of an electric bicycle must stop completely with the pedals stopped. Let’s see in the next sections what the sensors that allow this to happen and how to evaluate them.

Detection Sensors

The pedal detection system, therefore, allows you to communicate to the engine control unit when to activate.

There are two types:

Rotation or pedaling sensor: with this type of sensor the consent to the activation of the motor occurs at the same time as pedaling. This means in practice that the sensor sends the ignition signal of the engine only when it detects the movement of the pedals so that the first pedaling after a stop is completely borne by the cyclist.

Already at the second pedaling, however, the engine starts, providing a constant thrust that cannot be modulated according to the assistance level set by the user. This system allows the so-called symbolic pedaling, that is, it is possible to proceed without any real muscle effort, but letting yourself be carried entirely by the motor.

Remember, however, that to return to the category of electric bicycle, the engine will have to stop providing assistance when reaching 25 km / h, and will only be able to reactivate when the speed has fallen below this threshold;

Stress Sensor: this type of sensor detects the pressure exerted by the cyclist on the pedals, and has the advantage of being activated at the same time as the first pedal stroke, as soon as the foot presses on the pedal.

The type of assistance provided is modular, that is, it increases and decreases in relation to the effort we are making. This on the one hand makes pedaling more natural and that the cyclist is subjected to real physical exercise however light.

On the other hand, it is not possible to let yourself be carried entirely by the engine, since it stops as soon as it stops detecting the pressure on the pedals.

Although there is no absolute best sensor, since much depends on your needs and the use you want to make of the electric bicycle, the effort sensor has the undoubted advantage of keeping circulation and muscles active, and it is an excellent physical exercise for the less trained.

Assistance Levels

Both sensors can offer different levels of pedal assistance. It ranges from a minimum of two levels to grow, with an average between 3 and 5. Clearly, the greater the choice, the greater the possibility of adjusting the thrust we want to receive from the engine.

An engine with more than 5 assistance levels can be considered of high quality, while below 3 we are talking about low-performance economic engines.