Rear wing
The angle of attack of the rear wing. More angle tends to add total downforce — and drag — while shifting the aerodynamic balance rearward; less angle frees straight-line speed and moves the balance forward. Because the wing and the ride heights both set the aero platform, wing changes are usually paired with a rake adjustment to keep the overall balance where it was. Judge a wing change by both sector times and top speed, not by feel alone.
Effect by corner phase
More wing tends to add grip in medium and high speed corners while shifting the balance toward understeer.
The drag cost shows up on the straight that follows: more wing, less top speed.
Symptom tendencies
These describe tendencies, not rules.
Confident in fast corners but slow on straights
Less wing trades that security for speed — worth testing where the lap actually pays for drag.
Mid-corner oversteer — rear instability only in fast corners Mid-corner
More wing tends to plant the rear at high speed; check the balance has not gone to understeer everywhere else.
Verify on track before you commit to a change.