Tyre temperatures in ACC aren’t “nice-to-have telemetry”—they are a direct proxy for how effectively you’re converting load, slip and tyre energy into grip. The trick is reading the right temperature (core vs surface), at the right time (post warm-up), and interpreting patterns (inside/middle/outside), not single numbers.
Where ACC shows tyre temperatures
ACC exposes tyre temperature information in three practical places: the HUD tyre widget, the in-car HUD “telemetry” page, and the setup UI’s O/M/I readouts (Outside/Mid/Inside) in the garage.
Each tyre is divided into inner, middle and outer sections. Understanding how temperature is distributed across these zones is the first step to reading tyre behaviour and identifying how grip is being used on track.
On the HUD tyre widget, temperatures are typically communicated with a heat/overheat colour band, while the three segments per tyre correspond to O/M/I behaviour (useful for spotting lateral load and alignment effects).
If you want to see the split clearly while driving, you can cycle the HUD to the telemetry page as a workaround when pit/garage screens don’t preserve “last-lap” values reliably.
For setup work, the most underrated location is the Setup User Interface: O/M/I temperatures in the setup UI are designed to be close to surface temperatures, and can be checked in the pits (and even by pausing mid-corner to observe heat spreading).
When tyre temperatures matter
The first rule: don’t judge tyres on lap 1.
Even with tyre blankets, you need a short window for carcass/core temperature, brake heat and aero balance to stabilise into something repeatable.
Tyre temperature data is unreliable in early laps: surface temperatures fluctuate rapidly while core temperature is still stabilizing.
Only after a few consistent laps does the data reflect real tyre behavior and usable grip.
A practical workflow for practice/qualifying-style runs is:
- Out lap: build heat progressively; avoid huge steering angles and big wheelspin (they create surface spikes that mislead you).
- Laps 2–3: push at near-target pace to stabilise the carcass/core.
- After lap 3–4: start interpreting O/M/I spread and axle balance as “real” setup signals.
ACC’s tyre behaviour evolves with physics updates, which is why older rules can stop being reliable over time.
What “good” looks like in ACC: operating windows and O/M/I spreads
ACC defines a clear baseline: core temperature operating window roughly in the 70–100°C range, with core often stabilising around the 80–90°C region once up to speed.
But ACC also models surface temperature separately. Expect the surface to drop on long straights and spike under heavy combined load. Large variations across a lap are normal.
while large differences highlight load concentration and performance loss.
So the target shouldn’t be to keep a fixed surface number. Instead, aim for a consistent O/M/I spread.
Keeping the temperature difference across the tyre within a limited range helps ensure that the contact patch is working efficiently and that load is distributed correctly.
Interpreting the pattern:
- Inside much hotter than outside: the tyre is being overworked on the inner shoulder, often linked to alignment or load concentration.
- Outside hotter than inside: the tyre is rolling onto the outer shoulder, usually due to balance or driving style.
- Middle significantly different from edges: a structural signal that the tyre is not working evenly—this should be treated as a warning, not a full diagnosis.
What temperature really tells you about grip
The physics behind tyre temperature is straightforward: as temperature increases, rubber becomes more compliant and can generate more grip—up to a point.
Tyre grip increases with temperature up to an optimal window, then drops as overheating reduces efficiency.
Maximum performance comes from staying within this narrow operating range, not from running hotter.
Beyond that point, performance drops. Excessive heat leads to reduced efficiency, more slip, and a feedback loop where heat generates even more sliding.
This means temperature is not a linear indicator of grip. More heat does not automatically mean more performance.
The key takeaway is that temperature is a consequence, not a cause. It reflects how the tyre is being used, not what should be changed directly.
Conclusion
Tyre temperatures are not just numbers to keep within a range.
They are a way to understand how the car is using its available grip. If you read them too early, they mislead you. If you look at them in isolation, they tell you very little.
But if you analyse them at the right moment and focus on patterns rather than single values, they become one of the most powerful tools to understand where you are losing performance.
And once you see that clearly, improving lap time becomes a controlled process instead of guesswork.
