Every lap, a Formula 1 tyre is a little slower than it was the lap before — and the hard part isn't knowing that, it's knowing how much, and knowing it before the lap times make it obvious. By the time a driver is visibly struggling, the strategist is already late. So RaceHooks publishes four tyre numbers on every lap, built to answer the question a pit wall actually asks: how much longer can this set last, and what does it cost to stay out?
The four numbers we publish
These arrive as part of the analytics layer on every lap, per driver:
| Output | Range | What it tells you |
|---|---|---|
| Tyre health | 0.0–1.0 | How much usable performance is left in the set right now |
| Degradation rate | seconds / lap | How much lap time the tyre is losing per additional lap |
| Predicted cliff lap | lap number | The lap where degradation is expected to turn sharply non-linear |
| Cliff risk | low / medium / high / critical | A banded, at-a-glance read of how close the cliff is |
Tyre health is the headline figure, but it's the rate and the cliff that drive decisions. A car at 0.45 health losing 0.05s a lap is in a very different situation from a car at 0.45 health losing 0.30s a lap, even though the health number is identical.
Why raw lap times lie
The obvious way to measure degradation is to watch a driver's lap times climb. It doesn't work, because three other forces are moving lap time at the same time:
- Fuel burn makes the car faster every lap as it gets lighter — pulling lap time the opposite direction from tyre wear, and partly masking it.
- Track evolution makes the surface faster as more rubber goes down across a session.
- Traffic, dirty air, and lift-and-coast add noise that has nothing to do with the tyre.
A raw lap-time delta blends all of these together. Our tyre-state model exists to separate the tyre's contribution from everything else, and update that estimate as each lap completes — so the degradation rate you read is the tyre, not the fuel load or the track.
Anyone can read a timing screen. The value isn't the lap time — it's the part of the lap time that belongs to the tyre, isolated in real time. That's the number a strategy call actually turns on.
What "the cliff" actually is
Tyre degradation isn't linear. For most of a stint a tyre loses performance gently and predictably. Then it reaches a point — the cliff — where the surface or the structure gives up and lap time falls away fast. Crossing the cliff can cost more in a handful of laps than the entire preceding stint did.
That's why the predicted cliff lap is a separate output from the degradation rate. A gentle, steady rate can still be sitting two laps short of a cliff, and a strategist who only watches the rate won't see it coming. We model the cliff explicitly and publish the lap we expect it on, so the question becomes "do we pit before lap N?" rather than "does this feel like it's about to go?"
Reading cliff risk in real time
Cliff risk is the field built for glance-speed decisions. It collapses the health, the rate, and the distance-to-cliff into one banded signal:
- low — plenty of stint left; no action implied.
- medium — the window is opening; start planning the stop.
- high — the cliff is near; the undercut math is live.
- critical — pit now or pay for it.
The point of banding it is speed. During a live session nobody has time to integrate three continuous numbers in their head every lap; they need a signal that says act now the moment it's true. That's what cliff risk is for — and it's one of twelve production models running on every RaceHooks session.
Tyre health tells you what's left; the degradation rate and the predicted cliff tell you what it costs to stay out — and cliff risk tells you the instant that math flips.