Dirty Air

F1 cars make most of their grip from aerodynamics, which need clean, smooth airflow. Running closely behind another car puts you in its turbulent 'dirty air', cutting downforce, so the following car slides, struggles in corners, and overheats its tyres.

This is why following closely is hard and why overtaking often needs a big pace gap or an overtake aid. Recent rules aimed to reduce the effect, but it never fully disappears.