Undercutting

If you have watched any contemporary Formula 1 races especially after refuelling was banned by regulations, you have probably heard commentators speaking about undercutting. Besides the commentators undercutting is also a word repeatedly heard when engineers and drivers communicate during races via team radios. But what does undercutting actually mean?

Undercutting is a strategic move aiming at overtaking a car during pit stops. This can be a beneficial move, because in many circuits overtaking is difficult. Firstly, aerodynamics of F1 cars are not working correctly when following closely behind another car. Secondly, the opponent running in front usually defends his position and strive to select his driving lines to make an overtaking as hard as possible.

The idea of undercutting is to make a pit stop just few laps earlier than the opponent car you are trying to pass. Immediately after your pit stop you have new tyres on, and because of this, you can expect to be able to set faster lap times than your opponent with worn tyres. Consequently, if the difference in pace between you and the opponent car is large enough, the opponent will return to track behind you, after he makes his pit stop.

However, there is a cost in doing an undercut move. After both of you have made your pit stops, you are the one who is competing with more worn tyres. For this reason, you may run into trouble when the tyres begin to lose their grip. This gives your opponent a possibility to pass you back with fresher tyres. In worst case scenario your pace isn’t fast enough right after your pit stop so that the opponent comes back still in front of you. Now you are behind your opponent having older tyres than him. Not a good situation to be.

What are some other problems you may encounter when performing the undercut? In some circuits, if the weather is cold the new tyres may actually be pretty slow on first lap or two before they reach their optimal temperature. As you can imagine, this effectively prevents you raising your track position by undercutting.

Another issue that can ruin your undercutting tactic is safety car or virtual safety car appearing after you have pitted, but your opponent has yet to pit. In this scenario, your opponent can make his pit stop while you are driving under the speed limit. Naturally, you can’t make it in front of him if this is the case. Even worse, some other cars may also make their pit stops while the speed limit is on and you actually lose some track position. Generally speaking, pitting earlier than others always brings about the risk of losing positions if safety car emerges.

How to defend against undercutting? There are some ways to defend if you are the one driving in front of your opponent and the opponent is trying to overtake you by undercut.

Firstly, the best defence to undercutting is to stop on the same lap as your opponent. If these stops go smoothly, you should still have the better track position and your tyres will be as fresh as your opponent’s. However, in order to perform this tactic, you must guess correctly the lap when your opponent is coming in. Besides this, since you are driving in front of your opponent, the opponent will have a last second opportunity not to come in and change strategy when he realizes your car turning to the pit lane.

Secondly, if you anticipate that your opponent may undercut you, you can do your own pit stop first. Pitting first you are actually undercutting your opponent. Because of this, you can expect to be faster with the new tyres keeping your position. Moreover, you may even be able to have a little gap after your opponents stop. The downside of this move is that your opponent can now leave his stop a few laps later forcing you to defend your position with older tyres after both of you have stopped. An overtake on track may be a real threat now.

Both of these two defences against the undercut involves you to stop earlier than you would otherwise, so I call them early stop defence strategies. As you cannot know certainly when your opponent is making his pit stop, you really don’t know whether you are pitting before, simultaneously or after your opponent. In fact, you are just deciding how many laps earlier than planned you are going to stop. This means that both of the above mentioned defences can actually be two realisations of the same early stop defence strategy.

Another strategy for defending against the undercut is pitting later than planned. This way you almost certainly lose your track position for your opponent, but you will have benefit of fresher tyres after pit stops. Using this benefit your aim is to take your track position back by overtaking.

Very often the pivotal factor when considering undercutting is traffic. Undercutting requires one or more very fast paced laps between your and your opponents pit stops. Due to this, undercutting may go wrong if you are stuck in a traffic right after your pit stop. Whether it’s lapped cars or cars in the same lap they will still slow you down and these might be the crucial tents of the second you would need to get ahead when your opponent pits. In order to avoid this pitfall, the strategists of teams are always closely monitoring traffic situation on the track.

To summarize, undercutting is one of the most frequently seen strategic moves during contemporary F1 races and it certainly is often a brilliant move. However, the strategists and the drivers need to be very careful to decide when to use it and when not to use it.