Will pitting one lap before the car ahead get you past? On that lap you're on fresh tyres while they're still on old ones — the undercut works if what the fresh set gains on that lap is bigger than the gap.
Undercut works: the fresh set gains 1.41s on the lap — more than the 1.00s gap.
With these tyres the undercut window opens after 18 laps on the current set.
Where the gain comes from (one lap)
Worn-tyre loss+2.84s
Compound difference−0.08s
Out-lap warm-up−1.35s
Fresh-tyre gain+1.41s
Fresh-tyre gain by tyre age
The undercut works where the line is above the gap.
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
01020304050laps on the current setgap 1.0s
How it's calculated
Worn-tyre loss grows with tyre age at the rate measured for this circuit's compounds in the 2026 races.
Softer compounds are a little faster; a new set also needs a lap to come up to temperature, which costs time on the out-lap.
The pit stop itself costs the same whichever lap you take it, so it cancels out — only the one lap where the two cars are on different tyres decides the undercut.