Construction of the electric bike


Construction Son electric bike

A YouTube video traces the construction:

Bike or Car? The best solution to go forward!

" Electric bike? It is for the lazy! "That's what I told myself every time I was getting doubled by an octogenarian equipped with this unbridled 2 wheels! I persisted to get around by the force of my legs and inconvenience wet shirt arriving at work.

Why ride an electric bike?

Tableat1: Advantages / Disadvantages of conventional bicycle

  • One study showed that on average a bike traveling at 14km / h city ​​car 12km / h

Solution to the drawbacks:

  • Finally, the only way to combine the comfort of a small motorcycle to bicycle advantages is the electric bike. It removes the motivation problems that may occur on some mornings, wet t-shirt after a somewhat long coast.
  • Regarding exposure to weather, a good poncho will do.

Tableat2: Advantages / Disadvantages of electric bicycle



Middle green transportation

May ask too much physical effort

maneuverabilityand speed one would(1)

High risk of exposure to the elements

Easy parking


Low maintenance costs:

  • no insurance
  • affordable repairs


Solution to the drawbacks:

  • Regarding exposure to weather, a good poncho is still the case (even if the style is hard to follow)
  • The price to buy: You can find electric bikes from 600 €. However be aware that an electric bike good (battery with sufficient autonomy, robust engine, part duty cycle) is from about 1500 €.

There are then two ways to obtain this mode of transport:

  • Pay the sum required to access the 2-wheel dreams
  • Converting a conventional bicycle in 2-wheel of his dreams (can return to 1000 € cheaper than an electric bike of equivalent quality)

Construction of electric bike of his dreams

At first, I was party to convert my old racing bike in an electric bike. After reflection and some internet research, I found the old steel frame and roller brakes not robust enough to support the weight and power of the equipment.

Figure 1: Cycling race not strong enough to mount

The retro look of the Triumph is tasteful, I launched the challenge to start from scratch and build a hybrid electric bike and a small motorcycle.


  • Strong power, speed high with minimal couple (Allowing good acceleration)
  • Robustness
  • Lightness (It must be transported over short distances and allow access to trains)
  • modularity: Possibilitymaintain andimproveeasy 2-wheel based on future budgets

Construction of the mechanical part


Figure 2: Brand Framework Musing

The selected frame is a Dirt Bike frame imported from Germany. It is composed of reinforced aluminum tubes with the robustness and lightness required for onboard power cycling. Aluminum also has the advantage of corrosion resistance, making it insensitive to rain.

The fork

Figure 3: Steel Fork of the Ruff-Cycles brand

Good quality suspended forks being expensive, heavy and subject to more rapid wear, a rigid fork has been selected. Steel is a good shock absorbing material and allowing a slight vibration attenuation due to unevenness of the road.

The braking system

Figure 4: Brakes 180mm diameter disc

Disc brakes are virtually indispensable for motorized bicycles. They allow a more efficient braking. De180mm of discs are installed in the front and back for optimum braking.

The braking system is for mechanical compatibility with the electrical switching system and electromagnetic brake which can recover the energy lost during braking to reinject it into the battery.

The reinforcement of the fork lugs

Figure 5: Torque arm serving to reinforce the fork lug

conventional bicycle frames are not made to withstand large torques. It therefore is preferable to equip the reinforced steel rods called torque arms (fitted also some motorcycles)

Construction of the electrical part

There are several motorization kits for resellers bikes. sell very powerful kits (up to 2000W, allowing with good battery configuration and winding reach 80km / h) with an excellent value and a very responsive customer service offering a very effective aid mounting their operator set.

There are several possible to mount configurations depending on user expectations and physical.

The expectations (choice of coil)

Figure 6: Motor winding

There are many types of engines:

  • fast motor but little torque (350/480) [bike]
  • Moteurà high torque but low speed (180x280) [mountain bike]
  • Compromise between torque and speed (280x38O) [versatile]

The type of motor winding will determine its characteristics. But that's not all: the battery (36V, 48V, 60V) will also play on the performance: the higher the voltage, the higher the speed will be too. (The speed is proportional to the voltage)

The weight of the user (selection of the controller)

Figure 7: 17A Controller

The weight of the user and his bike will be important: the more the user will be heavier, the current supplied to the motor must be large (the torque is proportional to current). Power-E-bike sells controllers 17A, 22A, 28A, 35A.

CAUTION: the purchase of the battery, check that it is capable of providing continuous current max corresponding to the controller!

The seller will be the best advice for the configuration best suited to your needs.

Motor mounting

Figure 8: Motor mounting

The kits are compatible with most bikes. It may have to be slightly file the fork beaks in order to have optimal positioning of the axis of the wheel.

controller mounting

The controller is a system for centralizing command and control of the battery and the motor. It must be air cooled to prevent overheating. It is thus recommended to mount it in a sealed box.


The connections to be made are simplified thanks to the unique shape connectors. Also photos and mounting explanations are found on the manufacturer's website.

NB:In order to protect the circuit from an overcurrent, it was equipped with unfusible preventing exploitation of the battery. Moreover, the electric bike has been fitted with a switch locked to prevent its misuse by others.

Performances (figures)

Autonomy - Reloading

With a battery 12 A.h the electric bike has a range of 50kmabout (assisting the engine with a steady pedaling). To get an idea of ​​the autonomy (in km) that can provide a battery, simply multiply the value of its capacity (A.H.) by 4. Using the bike "motorcycle" mode autonomy will be no more than 35km about. Moreover, the bicycle is equipped with an electromagnetic brake, which uses the motor in generator mode and thus has the effect of charging the battery when braking.

Recharging the battery 12A.h lasts about 6h. (It depends on the loading system available)

NB: The battery life depends much on external conditions: wind, temperature, weight and build.

Speed ​​and torque

As has already been said, the speed depends on the battery voltage and torque Ducourant it can provide. (Andfinally your weight and wind direction)

With a battery 48V and a controller 17AThe electric bike can reach speeds of 45km/h Max and climb slopes15% at a rate of 22km/h.

Consumption and compared with a city car

Board 3: Consumption and compared with a city car (VW Polo 5)



Middle green transportation

maneuverability and city speed (1)

High risk of exposure to the elements

Easy parking

Purchase price

The chore of car trips punctuated caps and from conductors enervated turns into beautiful road trips!


Low maintenance costs:

  • no insurance
  • affordable repairs
  • requiring electric motor virtually zero maintenance unlike a conventional gasoline engine (oil change, filter change, etc.)


What you must remember

The construction of its own electric bike finally gives it a much greater sentimental value than if it had been purchased. Another advantage is that it normally has almost no secrets for you and you are able to repair nearly all failures.

The price of parts to purchase may seem a bit pricey (although some dealers have a very good value). The price depends on a lot of the equipment you want to integrate with your bike: hydraulic disc brakes / mechanical, aluminum frame, suspension, etc.Il necessary to choose between owning the latest iPhone or ride an electric bike.

Warning ! The electric bicycle is however not 100% green. We must not forget that the production of the batteries has a significant impact on the environment. But this impact can be "offset" using the bike over the car. The influence of the move also depends on the power source you recharge the battery. In France it comes to about 76% of nuclear power in Germany and about 20% of coal.

That's why the next target would be the acquisition of solar panels for the construction of a loading terminal 100% clean!

Finally, the electric bike is not a lazy affair, but people wishing to find an alternative to the car using a means of transport cheaper, more fun and ecological!

For questions about building your electric bike feel free to ask in the comment


VW Polo

Purchase price: 600-4000€

Purchase price: 15 000 €

Weight: 35 kg

Weight: 1100 kg

Costs: 0,002 € / km

(Maintenance + energy)

Cost: 0.3 € / km

(Maintenance + fuel)

Consumption: 12W.h / km

Consumption: 788W.h / km

Emissions de CO2 : 0 gCO2/km

Emissions de CO2 : 110 gCO2/km

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