What is the undercut in F1? Ask Mark

F1 befuddlement? Our GP editor is here to help. This month, the many F1 uses of 'undercut'

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Could you please explain the term ‘undercut’. It seems to describe a multitude of situations such as sidepods, pitstops, overtaking etc! And my mother used to ask for undercut at the butcher’s!
Jonathan Moorhouse, York

Hi Jonathan,

You’re right. It’s an over-used term. In F1, as opposed to the butcher’s, if it’s applied to the car it’s in reference to a sidepod undercut whereby there is a channelled-out section at the front lower corner, usually continuing down the side of the sidepod. It’s there to create a low pressure area which causes the air to accelerate there for aerodynamic benefit.

If it’s applied to race strategy it’s about coming in the lap before the rival ahead of you and getting onto faster new tyres as he is still on slower old ones, thereby giving you a chance to get past him, via the undercut.

It shouldn’t really be used as a description of an overtaking manoeuvre. But if it is, it’s usually referencing that retaliatory move where, after you’ve been passed into the corner, the other guy can’t slow down enough and runs wide, enabling you to repass him mid-corner.

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