development of e-bikes
E-bike design and development is a multidisciplinary endeavor that blends innovation in mechanical engineering, electrical engineering, and industrial design.
e-bikes and urban mobility
Electric bicycles, or e-bikes, are transforming urban mobility and personal transportation. Combining traditional bicycle mechanics with advanced electrical engineering, e-bikes offer a sustainable, efficient, and increasingly popular mode of transport. At this point e-bikes are responsible for up to 70% of sales of all bicycles.
The concept of the electric bicycle dates back to the late 19th century, but it is only in recent decades that advancements in battery technology, electric motors, and materials science have made them practical and accessible. Modern e-bikes are the result of continuous innovation aimed at improving performance, range, and user experience.
e-bike frames
The frame is the foundation of an e-bike, designed to support the added weight and stress from the motor and battery. Common materials include aluminum, which is lightweight and affordable, offering a good balance of strength and weight. Another option is working with carbon fiber, which is very light and strong but more expensive, and often used in high-performance models.
The frame design must ensure structural integrity, optimal weight distribution, and aesthetic appeal. Our engineers use computer-aided design (CAD) software to create precise models and simulate stress tests.
motor and battery
The motor is the heart of an e-bike, providing the necessary power assistance. There are three primary types:
- Front hub motors are located in the front wheel hub, they are easier to install but can affect steering.
- Rear hub motors are located in the rear wheel hub, providing better traction and a more natural riding experience.
- Mid-Drive motors are positioned near the bike’s bottom bracket, they deliver power directly to the bike’s drivetrain, offering superior weight distribution and efficiency, especially on hilly terrain.
The battery powers the motor and significantly impacts the e-bike’s range and performance. Lithium-ion batteries are the standard due to their high energy density, long lifespan, and relatively low weight. Key considerations in battery design include:
- Capacity, which is measured in watt-hours (Wh), determining how far an e-bike can ride on a single charge.
- Placement. Batteries can be mounted on the frame, integrated into the frame, or placed on a rear rack, influencing the bike’s balance and aesthetics. Today’s standard is that batteries are integrated in the downtube or seattube.
controller and sensors
The controller regulates the power flow from the battery to the motor based on input from sensors and the rider. It ensures smooth acceleration and efficient energy use. The display unit, typically mounted on the handlebars, provides vital information such as speed, battery level, and range. Advanced displays may also offer navigation and connectivity features.
Sensors are critical for responsive and efficient motor assistance. Common types include:
- Torque sensors measure the force applied to the pedals, allowing the motor to provide proportional assistance.
- Speed sensors monitor the bike’s speed, ensuring assistance is provided at appropriate times.
- Cadence sensors detect the pedaling rate, adjusting the motor’s power output accordingly.
strategy
The e-bike design process begins with concept generation and research.
We start off with research into the use of the bike, observations of riders, riding conditions, technological limits, innovation opportunities, company identity and many other factors that are important for a successful design project.
We also develop detailed idea’s about geometry, kinematics, drivetrain, components and sizing strategy.
The research leads to a strategy document with a clear innovation focus, potential risks and visual identity of the new mountain bike and serves as a strategic guide throughout the total project.
concept development
Through rapid cycles of sketching our senior designers investigate many potential rough ebike design idea’s and test this with early mockups.
We identify and choose the best e-bike design direction from all the possible ideas and make choices based on testing, experience and strategy.
During the concept design phase, we have a ‘look-in-the-kitchen’ session with your team. We present directions in sketch-form, functional and technical solutions, manufacturing solutions and mockups.
Together with your team we discuss focus, risk, level of ambition and push the design direction further into a concept that we will develop further.
engineering
The first important milestone during the design of new e-bikes is to bring the concept to a first fully functional prototype. This first prototype we call the P1.
To do so, we use powerful 3D CAD software to develop the bike. We design all frame parts, pivots, bearings, rockers and integrate standard components. In parallel we select materials, production methods, treatments, possible coatings and colors.
To achieve maximum performance at minimum weight we use 3D CAD simulations and tests with prototypes.
In addition to a set of 3D CAD files, a bill of materials and a first brief 2D package of drawings are made during the transition to production of the first P1 prototype.
prototyping
Both during the concept and engineering phases we build prototypes. Early prototypes are mostly more like mockups and are often 3D printed. We use them mainly for testing shapes, ergonomics and engineering solutions.
At the end of the engineering stage we build the first P1 full functional prototype. These prototypes are high quality, often CNC milled, coated, with graphics and fully functional.
The P1 prototype will be tested, both on functional, ergonomic and performance aspects. We document all the learnings and develop improvements in stability, cost, weight and performance. Mostly this leads to an updated prototype P2.
After one or sometimes more cycles of improvements the product is ready for manufacturing on a larger scale.
future of e-bikes
Developing e-bikes involves addressing multiple challenges. One of them is balancing capacity, weight and cost of the battery and motor combination to offer the best range, shorter charging times and lightest weight that fit to the bike we develop.
Another challenge is navigating varying regulatory landscapes regarding power limits, speed restrictions, and safety standards.
The future of e-bikes is promising, with ongoing advancements in technology and growing adoption worldwide. E-bikes will become even more connected, with integration of IoT technologies for enhanced connectivity, navigation, and security features. Advances in battery chemistry promising longer ranges, faster charging, less weight and greater longevity.
And finally in the e-mountain bike sports we see the newest small motors with maximum torques between 40 and 70Nm from companies like TQ, Fazua and Maxon which make it possible to build light e-mountain bikes with weights from only 12 kg. They have a fully integrated battery and motor and in terms of looks they are extremely close to a normal bike.
conclusion
Electric bicycle design and development is a complex, multidisciplinary endeavor that blends innovation in mechanical engineering, electrical engineering, and industrial design.
As e-bikes continue to evolve, they promise to play a pivotal role in the future of urban mobility, offering a sustainable, efficient, and enjoyable alternative to traditional modes of transport.
We are happy to discuss your project if you plan to develop a new e-bike an see how we can support.
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