When you load a session, AB Racing Line analyses your telemetry and produces two separate estimates of recoverable lap time: a Technique Gain from changes to your driving inputs, and a Setup Gain from car setup improvements. This article explains exactly how those numbers are built — what signals are used, what formulas are applied, and where the uncertainty comes from.
Technique gain is built up corner by corner from signals that are directly measurable in your telemetry. Only signals with a clear, calculable relationship to lap time are included. Signals that improve the feel of the car but cannot be directly converted to seconds — such as smoothness or trail braking style — are excluded from the number.
This is the highest-confidence estimate we produce.
We measure where you begin braking on each lap, averaged across all your clean laps. We compare this to the latest braking point consistent with the corner's speed requirement — derived from the car's average deceleration rate and the minimum apex speed needed to make the corner cleanly.
The time saved is calculated from basic kinematics:
For example: if you are braking 20 metres earlier than necessary at 150 kph (41.7 m/s), the recoverable time in that braking zone is approximately 0.48 seconds — before accounting for what you can do with that extra distance. We apply this calculation to every corner individually and sum the results.
Each marker shows where braking started on a single lap. The gap to the optimal late brake point is recoverable time every single corner.
We measure your average apex speed at each corner and compare it to the maximum the car's available lateral grip supports. The lateral grip ceiling is estimated from your own best G-circle utilisation across the session — we use your data, not a theoretical maximum.
The time relationship is:
Arc length is estimated from the GPS trace. Speed values are in metres per second. For example: a 5 kph apex speed gain through a medium-speed corner with an 80-metre arc saves approximately 0.07 – 0.12 seconds through that corner alone.
Coasting is defined as any moment where throttle is below 5% and brake is below 2% simultaneously. It represents time where no meaningful force is being applied to the car — the driver is in transition between inputs rather than using the available grip.
We measure the total coasting time per lap from your telemetry. The target is below 4% of lap time — a benchmark consistent with high-level amateur performance in most car classes. Not all coasting is recoverable; some reflects deliberate weight transfer technique. We apply a 60% recovery factor to the gap:
The amber zone is where neither throttle nor brake is applied. At 60% recovery, 0.8s of coasting yields ~0.5s of potential gain.
Full throttle percentage (throttle above 95%) is one of the strongest predictors of lap time. We measure what percentage of your on-track time you spend at full throttle and compare it to what the car's traction G data suggests is achievable given your corner exits.
The weighting accounts for the fact that not every moment off full throttle represents a recoverable opportunity — some are in braking zones or mid-corner where full throttle is not appropriate.
The conservative end of the range uses only high-confidence signals (braking point) at 80% of their calculated value. The optimistic end adds medium-confidence signals at their full calculated value. Both ends exclude low-confidence signals entirely.
Setup gains are inherently harder to quantify than technique gains because they depend on how the driver responds to a changed car. We use two measurable signals.
Incorrect tyre pressures reduce the size of the contact patch. An over-pressured tyre crowns in the centre; an under-pressured tyre cups at the edges. Both conditions reduce peak lateral grip.
The relationship between pressure deviation and grip loss follows established tyre physics:
A front-view cross-section of each tyre meeting the road. The shape of the tread tells you everything: a crowned tyre touches in the middle only, a flat tyre touches across its full width, and a cupped tyre touches at the edges only. The strip on the road below shows the actual contact patch — both over and under-pressured tyres leave grip on the table.
We measure your actual hot pressures from the telemetry (80th percentile of on-track readings to exclude outliers) and compare them to the target derived from tyre temperature profiles. The lap time equivalent is:
Cornering time fraction is the proportion of your lap spent cornering — calculated from your GPS trace and speed data. For most road courses this is between 0.55 and 0.70.
When the car has a handling imbalance — entry oversteer, exit understeer, or similar — the driver unconsciously applies corrective steering inputs to keep the car on line. These corrections are measurable in the telemetry as steering angle applied in the opposite direction to the corner.
We count the total time per lap where correction steering is active at corner-relevant speeds:
A setup change that resolves the imbalance eliminates the need for those corrections. We apply a 70% recovery factor because some correction time reflects driver habit rather than car imbalance, and habit takes time to unlearn:
The combined gain is not the technique gain and setup gain simply added together.
The reason: some of both gains occupy the same territory. If the car has an entry balance problem, the driver may be braking earlier than necessary to compensate for snap oversteer on turn-in — not because of their natural style. Fix the balance, and some of the "braking point gain" disappears because the driver was already at the right point for that car's behaviour.
We call this shared territory the overlap correction:
The overlap percentage is higher when attitude velocity data shows the car has a clear imbalance — suggesting more driver compensation is occurring — and lower when the car is well-balanced and the gains are genuinely independent.
0.8s technique + 0.4s setup − 0.1s overlap = 1.1s combined potential gain
To keep the numbers honest, the following are intentionally excluded:
We show a range rather than a single number because lap time prediction is not an exact science. The range represents our genuine uncertainty, not a hedge.
If your session had variable conditions (wet/dry transitions, significant tyre degradation), the estimates are flagged as lower confidence and the range is widened accordingly.
The goal is for the number we show you to be one you can actually achieve — not a theoretical maximum that makes the app look impressive but leaves you frustrated on track.