Why does the undercut work in F1?
The undercut works because fresh tyres are roughly one to two seconds a lap faster than worn ones, and that advantage is biggest in the first few laps of a stint. A driver who pits first uses those fast out-laps to gain time while the rival is still on old rubber, and emerges ahead once the rival finally pits.
The fresh-tyre advantage
A new set of tyres is around one to two seconds per lap quicker than worn tyres, and more than that when degradation is severe, with most of the gap coming in the opening laps after they are fitted.[2] The undercut exists to convert that short-lived pace advantage into track position.[1]
How the move plays out
The chasing driver pits first and loses roughly twenty to twenty-five seconds in the pit lane, but immediately banks a much faster out-lap than the rival, who is still circulating on tired tyres and setting a slow in-lap.[2] Stretched over two or three laps, the fresh-tyre gain offsets the pit-stop loss, so when the rival finally stops they rejoin behind.[1] This is why the undercut matters most at circuits where passing on track is hard.[1]
Why it does not always work
Two things can kill an undercut. The out-lap has to be in clear air, because rejoining in traffic throws away the fresh-tyre pace, and the new tyres must reach temperature straight away, so a slow-warming compound or a scrappy out-lap lets the rival respond and keep the place.[2]
:::analysis The undercut is really a bet on warm-up. A team commits to the stop believing the driver can switch the tyres on within a corner or two; if the out-lap is even a few tenths shy, the move fails and the leading car gets to choose whether to cover. That is why you so often see the car ahead dive into the pits the very next lap to defend its position.
:::
Related reading
- [1]F1 strategy explained: undercut, overcut and more (Motorsport.com) (motorsport). Accessed 2026-06-19.
- [2]How the undercut works in F1 (F1 Chronicle) (f1chronicle). Accessed 2026-06-19.