Stint

What it is

A stint begins when a driver leaves the garage or the pit lane on a fresh set of tyres and ends when those tyres come off (either at the next pit stop or at the chequered flag). The opening stint of a race begins on the formation lap; the final stint ends at the finish line^[1].

A driver's race strategy is described in stint terms: a "one-stop" is two stints (start tyre, second tyre), a "two-stop" is three stints, and so on. The race regulations require at least two compound types to be used during a dry race, which forces at least one pit stop and therefore at least two stints^[2].

Stint length

Each tyre compound has a target stint length based on Friday practice degradation models. Approximate guidelines for a typical race^[1]:

• Soft compound: 10-20 laps, varies dramatically by track temperature.
• Medium compound: 18-30 laps, the most flexible.
• Hard compound: 25-45+ laps, the longest survivor but slowest absolute pace.

These are rough. Specific stint targets vary per circuit, per compound, per driver, and per race-day conditions.

Why teams worry about stint length

:::analysis The race-strategy puzzle is essentially: given the available compounds, the planned number of stops, and the expected tyre degradation, what is the optimal sequence and length of stints?

A stint that is too short forces extra pit stops the team did not plan for. A stint that is too long pushes the tyre past its cliff and costs more time on track than the pit stop would have cost.

Every team's strategy team maintains a live stint model during the race. They update it lap by lap with actual tyre data, then re-run the optimisation to suggest the lap on which to pit. The race radio call "box this lap" is the output of that calculation. :::

In-lap and out-lap

A stint has a special first lap (the "out lap" starting from cold tyres) and a special last lap (the "in lap" ending with the pit-stop entry). See in-lap and out-lap.

Related

• Pit window
• Tyre degradation
• F1 tyre compounds explained