When the wind blows from the side, the sheltered zone behind the rider in front shifts diagonally rather than sitting directly behind. An echelon is the formation that accounts for this — riders fan out across the road, each sheltering the next. The angle of the echelon mirrors the wind angle. The problem: roads are only so wide, so echelons have a maximum size. Riders who miss the cut are left in the gutter, exposed to full crosswind, chasing at higher effort. This is how races shatter. Wout van Aert's move on stage 7 of the 2020 Tour de France is the textbook example — Jumbo-Visma formed echelons that split the peloton and eliminated several GC contenders in a single afternoon. Most amateurs never practise echelons because they require trust, discipline, and a wide, quiet road.