How a phone call about brake pads became Vetkuro's biggest test yet

When I started building Vetkuro, the idea was simple: connect my two passions. Motorsport, which has been my hobby and my weekend obsession for years, one I actively pursue on track days whenever I can. And technology, which is my profession and, in its own way, a passion too. Vetkuro was meant to be the product I'd want to use myself, built with the experience of someone who has spent years on both sides, behind the wheel and behind the keyboard.

The app went public a few months ago, and I've been sharing it mostly within the community I race with. And that's exactly where this story begins, because among those drivers is Tomek, the owner of Lava, a Polish manufacturer of sports brake pads and calipers. Lava is the same kind of project Vetkuro is: born from passion, built by people who race themselves, and developed with real attention to detail. When Tomek saw what we had built and what the platform could do, he spotted a synergy between our projects immediately.

Here's the thing: if you manufacture brake pads and calipers, you need a way to study how they actually behave on track. Not on a bench. On a real car, on a real circuit, driven hard. That requires telemetry, and that's where we come in.

In mid-May, my phone rang. It was Tomek, asking whether we could help run instrumented tests of his brake pads using Vetkuro.

I said yes during that same call. I also knew, saying it, that I was signing us up for a serious challenge.

Until that point, Vetkuro's hardware side was focused on logging driver data - GPS, accelerometer, and something secret (I don't want to reveal it now). Reading telemetry from temperature sensors and brake pressure sensors is a completely different problem. It meant extending our whole ecosystem: new hardware, new firmware, and changes across the software stack. We had less than two months to make it happen.

So we built one.

The result is the first revision of a new sensor hub - Senso. It reads analog and digital channels along with thermocouple temperature inputs, sampling at rates up to 200 Hz. That sampling rate matters more than it might sound: brake pressure changes in fractions of a second, and if you log too slowly, you miss exactly the part of the braking event you wanted to see.

In practice, this was two products' worth of work compressed into one summer. First, Senso itself , capable of reading analog signals, digital signals, and temperatures reliably in a race car environment. Second, our Akso logger had to be extended to communicate with Senso and record its data. And finally, everything had to be merged onto a common timeline with GPS, so that sensor logs and position data line up lap by lap, corner by corner. Getting synchronization right is unglamorous work, but without it, the prettiest data in the world is useless.

Those weeks were not one long string of successes. The newest GPS module we wanted to use turned out to be an immature product - the documentation promised better measurements, but we simply couldn't get it to perform, and a good chunk of time went into attempts to bring it to life before we cut our losses. Fortunately, we quickly found a replacement from a proven manufacturer, and that one did the job.

And beyond the hardware, there was the software layer: collected data has to be processed and displayed. Both our mobile app and our web analysis platform had to be adapted to show channels from the new device. It adds a lot of possibilities for the future - but in those two months, it mostly added a serious extra layer of work.

On August 3rd we met at Poznań Track (the largest and oldest track in Poland) with a properly prepared test car: a Mazda MX-5 belonging to Grzegorz, one of the top drivers in Poland's Miata Challenge, a driver with serious experience who is always willing to help test solutions in our community, Vetkuro included. That day, though, the star of the test was the braking system.

Tomek's goal was twofold, test the calipers Lava produces, and test different brake pad compounds against each other. The car was set up accordingly:

• Dedicated Lava calipers fitted with thermocouples - two per caliper, one on the inner side and one on the outer side, so heat distribution across the caliper could be observed, not just a single number.
• Two pressure sensors in the brake system, capturing how hard the driver was pressing the pedal and the pressure actually generated in the hydraulic circuit.

All of it flowed through Senso into the Akso logger, merged with GPS and driver data.

Then we drove. A lot. over to 250 kilometers on track over the course of the day.

And most importantly: the test went very well, from both sides of this collaboration. From Vetkuro's perspective, the Senso hub passed its exam - it captured the data we needed, session after session. Between runs, we could analyze results right there at the track, in the mobile app or in the browser. After each session, the full data set was also available as CSV files, ready for deeper offline analysis by the Lava team.

For Tomek, the day was just as productive. He could finally see, in numbers rather than impressions, which pad compounds generate what temperatures, how his calipers behave with different pads, and how all of it correlates with brake pressure. That's the difference between "the pedal felt good" and knowing exactly what happened at every braking zone.

This is the part I find fascinating, and it's worth explaining why anyone - a manufacturer, a team, or an ambitious amateur - would want this data.

Friction materials are brutally temperature-dependent. Every pad compound has an operating window. Below it, the pad doesn't bite. Above it, friction drops away and you get fade. Race-oriented compounds can operate across enormous ranges - some materials work from 150°C up to 800°C and beyond - but "works" and "works optimally" are two different things. Thermocouples on the caliper tell you which window you're actually in, lap after lap, and whether a compound is being used where it performs best.

Inner vs. outer temperatures reveal what a single sensor hides. Two thermocouples per caliper show whether heat is spreading evenly. Uneven temperatures can point to uneven pad wear, caliper flex, or cooling problems - things you'd otherwise discover only when inspecting worn parts after the fact.

Heat doesn't stay in the pads. Calipers and their seals have their own temperature limits, and brake fluid has a boiling point. When temperatures creep toward those limits, pedal feel degrades before anything visibly fails. Logging temperatures over a full stint shows you the trend before it becomes a problem mid-session.

Pressure data shows the other half of the equation. Brake pressure tells you how hard and how consistently the driver is braking - the initial hit, the modulation, the release. Combine it with temperature and speed, and patterns emerge: if the same pressure produces less deceleration as temperatures climb, you're watching fade happen in the data. And because everything is tied to GPS, you can see exactly where on the circuit the braking system works hardest and where it gets a chance to recover.

For a manufacturer, this is product development. For a team or driver, it's the same data working in the other direction - choosing the right compound for their car, their track, and their driving style, based on evidence instead of forum threads.

The devices that made this test possible are still in active development, and right now our focus is getting it into drivers' hands as soon as possible. I hope we'll be able to publish the full specification in the coming months.

My ambition is for Akso (logger) to be a universal solution - something you can use not only in a car, but on a go-kart, a motorcycle, or any other machine you take to a track. There's also a certain novelty in the works that I believe drivers will appreciate, but that one stays under wraps a little longer. The goal hasn't changed since day one -  telemetry at the highest level, accessible to everyone from amateurs, through committed track-day drivers, to professionals.

Two invitations to close with.

First, the Vetkuro mobile app is available now. Take it to your next track day, analyze your sessions, compare yourself with other drivers where shared sessions are available, and tell us what you think. We'll keep you posted on progress as the product develops.

Second, if reading this made you wonder what a setup like this would show in *your* car - ask us. If you'd like to test our devices and prototypes, or you need help adding sensors to your own vehicle, get in touch. Helping drivers instrument their cars is exactly the kind of problem we enjoy.

Finally, a sincere thank-you to Tomek and the whole Lava team for their trust, to Grzegorz for providing the car for these tests, and to the entire Vetkuro team, weeks of hard work went into making this day possible, and they delivered. Days like August 3rd are why this project exists.