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Chassis event detection

When a lap is saved (and when one is imported), the sample series is scanned once for four kinds of chassis events. They are stored with the lap, shaded onto the analysis charts, counted in the Sessions table (2L·1S·4B·1K), and summarized in the tuning panel.

Each event records its type, start/end distance, the wheels involved, and a severity score.

Lockup

A wheel turning slower than the car is moving, under braking:

  • Active tick: brake ≥ 20 % and any wheel's slip < 0.9
  • Minimum duration: 6 consecutive ticks (~0.1 s) — filters single-tick noise
  • Wheels: every wheel that crossed the threshold anywhere in the run
  • Severity: the minimum slip seen during the run (lower = harder lock; 0 = fully locked)

Wheelspin

A driven wheel overspeeding under power:

  • Active tick: throttle ≥ 40 % and any wheel's slip > 1.1
  • Minimum duration: 6 consecutive ticks
  • Severity: the maximum slip seen during the run (higher = more spin)

Suspension bottoming

Absolute suspension travel varies by car and tune, so bottoming is detected on the lap-normalized range per wheel:

  • compute that wheel's min/max travel over the lap; skip if the range is ~0
  • Active tick: travel within the top 2 % of the lap's range (≥ min + 0.98 × range)
  • Minimum duration: 3 consecutive ticks
  • Severity: how far into the range the peak reached (0–1)

Kerb strike

A kerb shows up as a single-tick spike in suspension travel rather than a sustained compression:

  • for each tick, compare against the average of its neighbors two ticks away: neighbors = (travel[i−2] + travel[i+2]) ÷ 2
  • Fires when travel[i] − neighbors > 35 % of the lap's travel range
  • Recorded as a zero-length event (start_dist = end_dist)

Caps and robustness

  • At most 40 events per type are stored per lap, so a spin-fest can't bloat the database.
  • Laps imported from old (v1) files that lack per-corner columns simply produce no events instead of erroring; events are recomputed on import when the data is present.

How events are displayed

  • Analysis charts — each event shades the panel that explains it: lockups on the Brake panel, wheelspin on Throttle, bottoming and kerbs on the suspension panels. The band is tinted in the lap's color at 14 % opacity, and single-tick kerb strikes are widened to a minimum of 2 m so they stay visible.
  • Driver aids — TCS-active stretches shade the Throttle panel and ASM-active stretches shade the Speed panel, using the same mechanism.
  • Sessions table — the compact per-lap code 2L·1S·3B·1K = 2 lockups, 1 wheelspin, 3 bottomings, 1 kerb strike.
  • Corner Detail widget — live LOCK / SPIN badges are re-derived per corner as you scrub, using the same thresholds (brake ≥ 20 % & slip < 0.9; throttle ≥ 40 % & slip > 1.1).