Magazine interview of the founder: the untold story of iruka development – why a transformer bicycle was needed
The following is a reprint of an interview with Founder Mark Kobayashi, published in the magazine “Folding and small-wheeled bike catalog 2019 (Tatsumi Publishing JPY 1,080), released on March 30, 2019.
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I started riding a folding bicycle for my daily commute, which gave me a strong desire to create a product perfectly suited for urban cycling. While I liked my first bike, I began to notice its shortcomings the more I used it, and ultimately, this led me to launch my own brand.
There were three essential criteria for the bicycle I envisioned: optimal performance for urban riding, a foldable shape for easy storage, and the ability to roll it easily when folded.
One key characteristic of urban riding, especially in Tokyo, is the abundance of traffic signals and intersections. For example, on my commute from Mejiro to Aoyama, there’s a signal every 200 meters on main roads and an intersection every 100 meters on residential side streets. This means frequent starting, stopping, slowing down, and accelerating.
Additionally, Tokyo is surprisingly hilly. Within the Yamanote Line area, for instance, Shinagawa Station is at an elevation of 2 meters, while Shinjuku Station sits at 37 meters—a 35-meter difference. Even Gotanda and Meguro, adjacent stations, have a 21-meter elevation difference. In coastal areas, while the terrain is flat, the ups and downs of bridges can’t be overlooked—for example, the Harumi Bridge ascends to 20 meters at its peak.
Thus, urban bicycles need not only basic attributes like speed and stability but also ease of starting, acceleration, braking, and gear shifting. Incorporating these requirements into the bike’s design, I carefully considered the frame structure and components.
Folding small-wheeled bikes often lose energy due to weak points at the hinge and long handle post. To address this, I designed a folding mechanism without a hinge on the top tube and opted for a telescopic handle post instead of the usual hinge style to ensure strength. People who test ride the bike often say that iruka pedals effortlessly.
For braking, I chose disc brakes for reliable stopping power, and for the drivetrain, an 8-speed internal gear hub with a wide range that allows shifting while stationary. Although this slightly compromises weight, I made no hesitation in prioritizing performance.
At my previous company, I would bring my folding bike into the office, but its folded height of 65 cm didn’t fit under my desk, as standard office desk clearance is approximately 62 cm. Initially, I considered reducing the folded height to under 60 cm. However, after I started traveling frequently with my bike, I aimed to reduce the folded height to below 50 cm. On the Shinkansen, the distance from the seat edge to the seat in front is 50 cm, and the seat width is also 50 cm. I realized that if the bike's folded dimensions were within 50 cm in both height and width, and it could stand vertically, it could be stored at my seat even when the rear storage space was unavailable.
The office of my previous company was located in the Otemachi Building, a famously long structure, where I sometimes had to carry my folded bike down hallways nearly 200 meters long, which was quite exhausting. I tried bikes with small casters but found they were not easy to roll smoothly. Then I thought, “Why not make use of the bike’s two existing wheels?” This led to the idea of folding the front and rear wheels so they remain parallel and coaxial in a free state. This requirement ultimately led to the adoption of a single-armed front fork.