- Spread = your slowest counted lap minus your quickest; typical lap = the median. Closing the spread is usually cheaper than a new best.
- The leaking sector is the one where your counted laps lose most, on average, against your own best of that sector.
- The brake-point spread says how far each corner's brake point moves lap to lap; once the least repeatable corner reaches 10 m, the debrief names it.
- The trend compares the second half of the session with the first, from four counted laps up.
Why consistency comes before pace
Your best lap is a single event. Your typical lap is what you can do on demand — and on demand is what races, qualifying runs and league nights are made of. A race is thirty typical laps, not one good one. A qualifying run is one attempt, and the driver who can reproduce their best lap has it every time they try.
Consistency is also the cheapest time available, because you have already proved you can drive the fast lap. Nothing new has to be learned to close the gap between your typical lap and your best — only repeated.
Those are the figures for the eight-lap example session used across these guides — a synthetic session built from StintLab's demo laps, run through its own report code. In a race, the difference between the typical lap and the best lap would be 0.227 s a lap; over twenty laps, 4.5 seconds.
Spread and the typical lap
Here is every flying lap of the session against the best counted lap. The binned lap is drawn too, because it is part of the story — but it is not counted:
- Spread is the slowest counted lap minus the quickest: 1:21.558 − 1:20.950 = 0.608 s.
- Typical lap is the median of the counted laps: 1:21.177. The median rather than the average, so that one bad lap barely moves it.
StintLab shows both in one tile — Consistency, with the typical lap under it — and says it in words in the debrief:
Your counted laps spread 0.608 from quickest to slowest, typical lap 1:21.177. Closing that gap is usually cheaper than finding a new best.
StintLab session report · debrief
Which sector is leaking
A spread says how much. The next question is where. For each sector, StintLab takes every counted lap's time through it, subtracts your best of that sector, and averages the result. The sector with the biggest average loss is the one leaking — measured against your own best of it, so it is about repeatability, not about a faster driver.
| Sector | Your best | Average counted lap | Average loss |
|---|---|---|---|
| S1 · leaking | 28.383 | 28.644 | +0.261 |
| S2 | 28.172 | 28.254 | +0.082 |
| S3 | 24.112 | 24.274 | +0.162 |
Sector 1 is where it goes: across 6 counted lap(s) you were on average 0.261 off your own best S1 (28.383).
StintLab session report · debrief
The printed report draws the same thing as bars under Where the time goes — “how far each sector was from your own best of it”. Averages are deliberate here: one scruffy lap should not decide which sector you work on, and a sector that is sometimes quick and often slow is exactly the one to fix. In the example it is the first sector.
Which corner wanders
Within the leaking sector, the brake point is the first thing to check. The printable session report lists every braking zone of your best lap, finds the same corner on each of your other counted laps, and says how much the brake point moved — the standard deviation, in metres:
| Corner at | Entry | Minimum | Peak brake | Zone | Time | Brake point varies | Laps |
|---|---|---|---|---|---|---|---|
| 500 m | 304 kph | 83 kph · gear 2 | 87% | 160 m | 3.84 s | ±16 m | 6 |
| 1,640 m | 320 kph | 114 kph · gear 3 | 84% | 160 m | 2.93 s | ±0 m | 6 |
| 2,440 m | 320 kph | 134 kph · gear 3 | 84% | 160 m | 2.73 s | ±0 m | 6 |
| 3,300 m | 307 kph | 126 kph · gear 3 | 87% | 160 m | 3.06 s | ±0 m | 6 |
| 4,240 m | 320 kph | 144 kph · gear 3 | 84% | 160 m | 2.65 s | ±8 m | 6 |
Your brake point at the 500 m corner moves about 16 m lap to lap — the least repeatable braking of the lap, and the first place to look for the consistency above.
StintLab session report · debrief
A brake point that moves 16 m lap to lap produces a different corner every lap: a different entry speed, a different minimum, a different exit. Fix it with a reference — a board, a kerb, a shadow, a change in the tarmac — that you commit to every lap, and watch this number fall. The braking points guide goes further into what the table means.
Did you get quicker, or drop off?
With four or more counted laps, StintLab splits them into two halves in the order you drove them and compares the average of each. In the example the first half — laps 2, 3, 5 — averaged 1:21.243, and the second — laps 6, 7, 8 — 1:21.101:
You got quicker as the session went on — the second half averaged 0.141 faster than the first.
StintLab session report · debrief
When it goes the other way, the sentence is careful about cause: “You dropped off as the session went on … Tyres, fuel or concentration; the lap times alone cannot say which.” On F1 25 laps, the fuel and tyre history — wear and temperatures per lap — is where to look next; see fuel, tyres and pit stops. If the tyres were fine, it was probably you, and shorter runs with a break between them are the cheapest fix.
Invalid laps are an inconsistency too
The quickest lap of the example evening was lap 4, at 1:20.623 — and it set nothing, because it was invalidated. StintLab keeps it on the list, marked invalid, and says so in the debrief:
1 of 8 lap(s) were invalidated and set nothing, however quick they were. Track limits are the cheapest time on this page.
StintLab session report · debrief
StintLab is stricter than the game here: cut a corner anywhere and the lap stays invalid to the line, even if the game clears its own flag first. A lap that is quick because it used more track than allowed is not a lap you can repeat in a race.
A consistency routine
- Measure first. Drive a run of eight to ten laps at a pace you could hold for a race. Note the spread, the typical lap and the leaking sector.
- Fix the wandering corner. Choose a brake reference for the corner with the widest brake-point spread and commit to it every lap.
- Drive at nine tenths. Aim for laps inside a window around your typical lap rather than for a new best. Invalid laps count as misses.
- Re-measure. Same car, same track, same conditions. A narrower spread with the same best is progress, and each session's Consistency tile will show it.
- Then chase. Once your typical lap is close to your best, chase a faster target — the practice plan will point at corners, not at noise.
Questions
What is a good lap time spread?
There is no universal number: it depends on the circuit, the car, the session and the tyres. The useful comparison is with yourself — the same circuit and car, session after session. A spread that narrows while your best holds still is real progress, even if the best lap never moves.
Why does StintLab use the median for the typical lap?
Because one bad lap should barely move it. The median is the middle counted lap: a spin or a lock-up makes the slowest lap slower and widens the spread — which is right, it happened — but it barely moves the typical lap, where an average would absorb the whole cost of the spin.
Do invalid laps count towards consistency?
No. Only counted laps — valid, timed, driven from the line and not through the pits — go into the spread, the typical lap, the sector averages and the trend. Invalidated laps are counted separately, because losing laps to track limits is its own kind of inconsistency.
Why is there no consistency figure for my session?
A session with one counted lap has nothing to spread, so the Consistency tile shows a dash rather than a zero. The trend needs at least four counted laps to split into two halves.
In a race, does fuel burn affect the trend?
Yes, in both directions at once: the car gets lighter and quicker as fuel burns, and slower as the tyres wear. The trend sentence reports only what the lap times did — it says outright that tyres, fuel or concentration could be the cause, and the fuel and tyre history is where to look.