FITA – Adjustable Children’s E-Bike

The Problem

The rate of children’s outdoor play has declined significantly in recent decades, with the popularisation of children’s television encouraging more time spent indoors, meaning time spent outdoors now is well below that of previous generations. This trend has raised concerns among researchers, educators, and parents, as outdoor play is known to be vital for children’s physical health, cognitive development, and overall wellbeing. Findings from the Royal Children’s Hospital National Child Health Poll (2023) highlight the extent of this issue, revealing that although 94% of parents acknowledge the importance of outdoor play, fewer than 45% of Australian children engage in it on most days.

This project seeks to encourage children’s independent outdoor play by promoting the developmental benefits of engaging with natural environments. In response to these findings, the proposed solution is an electric-assisted bicycle designed to grow with the child, supporting active exploration and long-term outdoor engagement.

Solution

Research findings indicated that children, regardless of age, naturally seek out the most challenging—and often the most risky—activities or equipment in playgrounds. This instinctive desire for challenge and risky play is innate, driving children to push their limits, grow, and explore new experiences. Analysis of survey responses revealed that the most active children were often drawn to bicycles as their primary form of outdoor play, whereas less active children either did not own bikes or were too young to ride.

These insights informed the decision to develop a new and innovative bicycle design aimed at encouraging children to spend more time outdoors, exploring, exercising, and engaging in independent play.

Fita has been designed to grow with its rider, offering exceptional adjustability to suit a wide range of user needs. Both the user and carer can easily and quickly tailor the stand-over height, seat height, and handlebar height and angle for a comfortable and safe fit. This level of adaptability allows parents to invest in a single bike that evolves as their child grows, eliminating the need for multiple frame sizes over time.

To accommodate this flexibility, several key components of the bike were designed to be adjustable. The primary adjustment point is the hardtail, which supports the rear wheel and brake assembly. By allowing the hardtail to move, the bike achieves a tailored ride height and improved stand-over clearance, capabilities uncommon in most bicycles. This design innovation not only enhances user comfort and ergonomics but also streamlines manufacturing by reducing the number of frame sizes required.

Technology

Manufacturing

Additional efforts to make Fita more cost-effective focused on the manufacturing process. Traditional bicycle frames are typically composed of complex tubular structures arranged in triangular formations. While this configuration offers excellent strength-to-weight performance, it remains challenging and expensive to produce due to the difficulty of joining round tubes at varying angles. The manufacturing of tubular frames is labour-intensive, requiring significant hand finishing and welding, which further increases production costs.

To address this issue, multiple design iterations explored alternative construction methods. Drawing inspiration from automotive manufacturing, where steel stamping is used to produce both structural and aesthetic panels efficiently, this technique was adapted for the Fita frame. The main components, including the frame, forks and hardtail, are fabricated from 2 mm 7005-T6 aluminium sheets that are laser cut, stamped and then laser welded.

Aluminium 7005-T6 was selected for its exceptional strength-to-weight ratio (approximately one-third the density of steel), its high formability for automation, and its natural corrosion resistance. This method avoids the labour-intensive tube bending, mitring and manual welding of traditional frames, enabling the production of strong, complex structures with a large central compartment for the battery and motor controller assembly, quickly and consistently.

These manufacturing methods are also well suited to robotic welding and assembly. As production scales and more units are sold, increased automation can reduce costs, cut production time, improve quality consistency, and further enhance affordability. The ready availability of 7005-T6 aluminium keeps material costs low, delivering a lightweight, durable, and cost-effective e-bike frame that becomes even more economical as production volumes grow.

1:5 Scale Prototype