Feeling like Gokumonto Island – The story behind the development of iruka C (Part 1)
We’ve announced the launch of a new model, iruka C. Using the same frame as the original S, this value-oriented iruka is crafted to deliver enhanced comfort for urban riding. Priced at 179,800 yen (excluding tax) in Japan, it’s around 36,000 yen more affordable than the original 8-speed model, including tax. I must say, it’s a product I’m truly proud of, just like S. Here I'm going to share the background and features of iruka C across several posts.
When I heard that the lead time for Shimano’s Alfine 8 was 12 months, I couldn’t believe my ears.
“Did you say 12 weeks?” I asked in disbelief. Magum, my partner who manages the supply chain in Taiwan, replied apologetically. “No, it’s really 12 months.”
Previously, the Alfine 8 gear hub we use for iruka could be shipped just weeks after placing an order. Now, it would take a full year.
iruka is built from 46 original parts made by ourselves and 31 off-the-shelf parts provided by suppliers. Including small metal parts like bolts and washers, the total number is even more. If even one of these is unavailable, iruka cannot be completed as a bicycle.
This meant we would have nothing to sell for nearly a year.
The second lot of iruka, shipped in early 2020, included the original silver color along with two new options: Storm Gray and Black. The sales had been steady from the start, especially in overseas markets, where the inventory was expected to run out by summer.
Though I didn’t have any experience in the bicycle business or even in the manufacturing industry, I knew exactly this: low inventory is fine, but no inventory is a problem. We needed to start production as soon as possible.
Our OEM factory in Taichung had previously told us that iruka’s lead time was 60 to 90 days. If we placed an order during the summer, we should be able to ship the next batch by winter. Confident in this timeline, I decided to place an order for more than double the last quantity and reached out to Magum in July 2020. And that’s when the conversation at the beginning of this story happened.
Due to the global surge in demand for bicycles, driven by the COVID-19 pandemic, lead times for all components—especially those from Shimano, the world’s largest bicycle parts manufacturer—had become drastically longer. Lockdowns and travel restrictions further disrupted labor availability and logistics. From what I heard, not only small brands like iruka but even major global brands were being affected. There was no backdoor solution to this problem.
Magum reached out to me, prefacing his message with, “Mark, you might not like this idea.” He informed me that Shimano had launched a new internal gear hub, the Nexus Inter 5, which could be delivered sooner and at a slightly lower wholesale price compared to the Alfine 8.
The Nexus series previously included 3-speed, 5-speed, 7-speed, and 8-speed hubs, but the 5-speed variant had been discontinued. I learned that this was not a revival of the old model but a newly developed product designed specifically for e-bikes.
Switching from the Alfine 8 to the Nexus Inter 5 would mean downgrading from 8-speed to 5-speed—Magum assumed I would reject the idea. However, what immediately came to mind was the possibility of creating a new 5-speed model with different specifications, while keeping the 8-speed model in production. To be honest, this idea had been simmering in my mind for a while. Before the launch of iruka, I had considered releasing both an 8-speed and a slightly more affordable 5-speed model at the same time. Ultimately, I decided to focus on a single model for the launch. The discontinuation of the Nexus 5-speed at the time also left me with no choice. Still, the concept of a 5-speed model had lingered like glowing embers in my mind.
The original 8-speed model emphasized a sharp riding feel, complemented by 1.25-width tires, a slim saddle, and flat handlebars that encouraged an aggressive posture. While I believe these were the right choices, I also knew some Flippers (as iruka owners are called) swapped to 1.50-width tires or thicker saddles for added cushioning. Others wanted more relaxed handlebars positioned closer for upright riding.
It was at that moment that news of the new Nexus Inter 5 came to me and I realized. By pairing this 5-speed hub with wider tires, a thicker saddle, and riser handlebars for a more relaxed position, we could create a more affordable, comfort-oriented iruka.
I felt like Ryonen, the monk from Yokomizo Seishi’s detective novel *Gokumonto Island*. He had been tasked with carrying out a symbolic murder using the temple bell, but had given up, feeling half-relieved, when the bell was requisitioned for the war effort. However, when the bell returned after the war, he took it as a divine sign and proceeded with the murder.
When I shared the idea for the new 5-speed model to Magum and the president of the OEM factory, they enthusiastically agreed. The factory quickly placed an order for the Nexus Inter 5 with Shimano, and we began refining the specifications. The model name had yet to be decided.
Here’s where we’ll leave off for today. Stay tuned for the next installment. The photo above features the iruka C in its new blue color.
That’s all for today. More to come. The photo above shows the iruka C in its new blue color.
Masaki Mark Kobayashi
Founder and President, iruka Inc.