IR25 "Ruby"

The IR25 “Ruby” marks the next big step for the team after the IR23 in our push back toward competitiveness.

At the core of the car was a completely new concept: all-wheel drive with four wheel hub motors. On top of that, we designed and built an entirely new monocoque. One of its standout features is a set of modular inserts at the suspension mounting points, giving us the freedom to adjust suspension hardpoints in the future without needing a completely new monocoque mold every time. That saves huge amounts of cost, time, and manufacturing effort. The payoff: more torsional stiffness, less weight. We also laminated the front axle cable ducts directly into the monocoque from the start.

But the real headline was the drivetrain. Making the jump from a rear-wheel-drive car with driveshafts to an all-wheel-drive package with wheel hub motors was a massive challenge. Uprights, gearbox, suspension kinematics — all of it had to be redesigned from the ground up. The steering system, of course, was redone as well.

And the complexity didn’t stop there. Four motors mean four inverters, which forced a complete repackaging of the inverter housing. At the same time, the aero package was also set for a major step forward. As part of a bachelor’s thesis, a brand-new front wing was developed with a clear focus on cornering performance. The sidepods and rear wing were also taken to the next level, with the cooling pumps integrated directly into the sidepods for the first time.

A leap like this is never smooth — and we felt every bit of it. Hit by inverter problems, we only got the rear axle inverters running in the night before leaving for Formula Student Germany — and even then, only with severe power limitations. The front inverters were still not installed at that point.

Even so, one thing became obvious straight away: we had made a big step forward in reliability. Apart from one unlucky failure in the acceleration queue, we managed to compete in every dynamic discipline, complete the endurance event, and even take home the Design Award at the Crazy 20 Event.

The motor power issues stayed with us throughout the event. In reality, that meant we were running rear-wheel drive only, and with heavily reduced power on top of that. The root cause was only found and permanently fixed weeks later: a tiny metal chip, barely visible even under a microscope, had caused faulty signals on one of the PCBs.

Looking back, this season was still an enormous achievement. To put a running car on track again after a development step this big in just one year says everything about the team’s spirit, determination, and drive to fight its way back to the front.

Just like the jump from 2023 to 2024, this revolution is now followed by evolution. So stay tuned — we’ll be back next year.

And this time, with real all-wheel drive.

– Ciao