Interview: Eugène Herben

Gravaa’s ability to let riders adjust tire pressure while riding — higher for smooth tarmac, lower for rough gravel, mud, sand or snow — all at the push of a button, is the sort of idea that seems obvious once you hear it, but the engineering required to make it real is anything but simple. The system packs a miniature pump, valves, electronics, and a power source into the hub, using the wheel’s rotation to power inflation or deflation on demand. That’s a lot of tech in a tiny space.

However, no matter how natural Gravaa feels, one big challenge remains: full tubeless compatibility. Many gravel and mountain bike riders, as well as road cyclists, run tubeless tires, which use liquid sealant to seal punctures automatically. That sealant is exactly what can cause trouble for Gravaa’s airflow pathways, clogging filters or damaging parts. Making the system work flawlessly with tubeless setups, without compromising reliability or ease of use, is one of the most challenging tasks facing Gravaa’s Chief Engineer, Eugène Herben and his team.

Throughout a wide-ranging conversation, we sat down with Eugène to discuss his career, the cultural quirks of the Netherlands, the origins of Gravaa, and the complex interplay between engineering innovation and cycling tradition

 

Photo: Beau van Hout

Hello Eugène! Let’s start with you — where you’re from and how you came into engineering.

Eugène: I’m from the very south of the Netherlands — the hilly part. People don’t always realize Holland isn’t all flat. Culturally, that region is a mix: Dutch, Belgian, German, and French. It was even part of France until about 150 years ago. That’s probably why my parents gave me a French name, Eugène. In English, it becomes “Eugene,” which is fine, but in Dutch, we like our short, strong names!

I trained as a mechanical engineer, starting in the automotive sector with General Motors. I worked on simulations, load calculations, and very specific components of large projects. It was interesting but unfulfilling because I never got to see the whole product come together.

Later, I moved into medical equipment, specifically ventilators, within a product solutions agency that solved engineering problems for many different types of clients. It was a good move because it allowed me to work on the entire system, from pneumatics and valves to control electronics and manufacturing. And funnily enough, the principles behind ventilators — a pressure source, controlled airflow, sensors, a power supply — are very similar to what we now do in the Gravaa wheel hub. The stakes are just a bit different!

How did the Gravaa story begin for you?

Eugène: Before I joined the team, I was already talking with colleagues — mostly cyclocross and MTB riders — about the idea of changing tire pressure while riding. We considered creating a home prototype. We already worked with pumps and pneumatics, so it made sense to us.

Then Gertjan (Gravaa’s founder) came into the company I was with and presented exactly that idea, which he’d been working on for a while. He even had a basic prototype to show us with all of the essential elements in place. The managing director of the business knew I was interested in this area and let me take the lead.

From the first meeting, Gertjan and I had a warm working relationship. That’s rare. I’d run my own company before, and partnerships can be tense if they’re just based on complementary skills. This was different: shared enthusiasm, mutual trust. That kind of relationship shapes the product in ways you can’t measure on a CAD model.

Photo: Beau van Hout

Let’s go into the tubeless challenge. A lot of readers will be thinking, “Why isn’t this already solved?”

Eugène: Tubeless tires use a liquid sealant inside to plug punctures. Our system moves a lot of air through the hub — about 60 liters per minute when deflating — and that airflow can carry sealant into the system. Once that happens, it can clog filters, gum up valves, or even damage parts.

It’s a paradox: sealant is designed to block any opening, and we are deliberately creating an opening to let air in and out. So the very thing that makes tubeless work also stops our system from working if we don’t protect it.

We’ve experimented with multiple strategies, such as centrifugal force to keep sealant away from the inlet while the wheel spins, labyrinth air paths that make it harder for liquid to travel into the system, and even special coatings to repel sealant. 

The key is that there’s no single “hero fix.” We’re developing a combination of measures that together will make tubeless possible without compromising performance or reliability.

 

How far along is that work?

Eugène: We’ve had prototype tubeless systems running with the Visma–Lease a Bike team for two or three years. They work in that environment because we control the conditions. For the public, it needs to survive years of riding, be user-friendly, and handle a wide range of sealants and conditions. We won’t release it until it’s ready. Our next product will be the Boost version for mountain bikes. After that, tubeless becomes the top priority.

 

Photo: Beau van Hout

Do you have any thoughts on what might follow tubeless technology?

Eugène: I see a future where adaptive pressure systems combine with self-healing tire technologies — so you’d have puncture resistance and optimal pressure adjustment in one package. That’s the ultimate goal. For now, though, our priority is to make every product we release bulletproof in the real world. If a rider puts their trust in our system, it has to deliver every time.

 

You’ve said before that cycling has its purists. How do you see Gravaa fitting into that?

Eugène: Some riders want everything traditional: steel frames, no electronics, no suspension. I understand it — I’m nostalgic about some things too. But as an engineer, I lean toward innovation when it genuinely improves the ride.

Our system is a positive product: it can improve comfort, safety, and performance without taking away from the experience. You could have a classic Italian steel bike with our wheels — nostalgic and modern at once.

Photo: Beau van Hout

Let’s go back to your first ride on the system.

Eugène: Well, the first prototypes were noisy, underpowered, and had torque resistance you could feel. But even then, you got a sense of the power and potential of adaptable tire pressure and how transformative it could be. Once we refined the mechanics, the torque ripple — the variation in resistance as the pump turns — was almost imperceptible. The system takes a few watts to run, but in real-world gravel or cobbled racing, the comfort and control gains outweigh that completely.

Now, I ride it daily on my gravel bike. Even on smooth tarmac, I sometimes drop the pressure for a section of cobbles, then pump it back up for the road. I can’t imagine not having it. It really is magical and completely natural - one of those, ‘why didn’t we have this before?’ products. I’m biased, of course, but as an engineer, I’m not given to praising something that doesn’t meet a certain standard.

Let’s talk about Boost.

Eugène: Mountain bike tires have far more volume than road or gravel tires. Deflation is no problem, but inflation is. We’re changing the pump configuration to give 25–50% more capacity, so even big MTB tires inflate quickly enough to feel seamless to the rider.

The Boost version will max out at around three bars, which is more than enough for mountain biking. The road and gravel versions can go much higher, but MTB doesn’t need it. We expect to release Boost in the near future, after thorough field testing.