F1 Undercut Explained: Why Pitting First Can Win a Race

An undercut is a pit stop made earlier than a rival's so that fresh tyres produce a faster out-lap and in-laps, letting you emerge ahead when they stop a lap or two later. It works because new tyres are quicker than worn ones, and because the car ahead is stuck on old rubber for the extra laps. At a circuit where overtaking on track is hard, such as Marina Bay, it is one of the few legal ways to pass someone without passing them.

The rest of this piece explains how it works, when it fails, and what to watch for at the Singapore Grand Prix on 11 October 2026.

What is an undercut in F1?

Imagine two cars. Car A runs ahead, Car B follows closely. On lap 20, Car B pits and fits fresh tyres. Car A stays out for a few more laps on tyres that are ageing and getting slower. When Car A finally stops, Car B has already banked several quick laps on fresh rubber, and may now be ahead.

The name comes from going "under" the car in front in time rather than in space. You never need to pull alongside anyone. You just need the time you gain on new tyres to exceed the time you lose in the pit lane, plus whatever gap you started with.

Why does the undercut work?

Three things combine. First, tyres lose performance as they wear, so a fresh set is faster than an old one by an amount that grows with each lap the old set has run. Second, the pit stop costs a roughly fixed amount of time. Third, the out-lap on new tyres is usually still quicker than a lap on tired ones, even though the tyres are not yet at working temperature.

When the fresh-tyre advantage per lap is larger than the gap between the cars, the maths works. If it is smaller, the car behind just loses time in the pit lane for nothing.

When does the undercut fail?

There are four common ways.

Traffic. If the car comes out of the pits behind a slower car, the fresh-tyre advantage is spent following it. This is the classic reason a perfect-looking undercut gets ruined.

Cold tyres. If the compound takes a while to warm up, the out-lap is not as fast as expected and the gain shrinks.

The response. A team that sees the rival pit can pit on the next lap and cancel the move. This is why you will sometimes hear a driver told to stay out only to be called in a lap later.

The gap. If the cars are far apart, the arithmetic never reaches. An undercut is a tool for cars that are already close.

What is the overcut?

The overcut is the opposite idea: stay out longer, use clear air to set fast laps on old tyres, and pit later. It tends to work when tyres hold their pace well or when leaving the pit lane means rejoining in traffic. It is less common than the undercut, and it is the answer to the question "why did they not pit when everyone else did?"

Why does this matter at Singapore?

Marina Bay is a narrow street circuit where passing is difficult. That makes strategy a larger part of the race than on a wide track with long straights. We covered the circuit's demands in our Marina Bay explainer, and the same logic applies here: if you cannot pass on track, the pit lane becomes the passing zone.

A caution, which is also a joke: the undercut looks brilliant on the radio and cruel in traffic. Before you decide a team made a strategy blunder, check where the car came out.

What should you watch for?

On Sunday, watch the gaps in the top ten around the first stops. If two cars are within a couple of seconds, an early stop from the car behind is an undercut attempt. If the car ahead responds on the next lap, the attempt has been covered. You can follow the stints and pit windows live in telemetry, and if you have a strong view on who gains from the first round of stops, make your Singapore predictions before lights out.