Qualifying, race, and wet-weather setups

One dry baseline does three different jobs: a single clean qualifying lap, a 20-to-60-minute race stint, and a low-grip wet track. The car is the same; the priorities are not. Qualy chases peak grip on light fuel and fresh tires, the race wants a repeatable lap on a heavy tank, and the wet wants mechanical traction on a surface that punishes aggression. Most of the time you are not building a new setup — you are deciding which way to move levers you already understand.

Qualifying setup — everything for one clean lap

A qualifying setup is a knife-edge tuned for one lap and discarded. It can be undriveable on lap 8, and that is fine, because it only has to survive the flying lap.

Strip the fuel

Fuel is dead weight, and weight is the single biggest free gain in qualy. On an iRacing road car, 3 to 5 US gallons covers an out lap plus a flying lap plus an in lap depending on track length — do not roll out on a full race tank by accident. Roughly every 10 kg of fuel costs on the order of a few hundredths up to ~0.1s per lap depending on the circuit, so a near-empty car finds time before you touch anything else. The classic mistake is a sim crash reloading your full-fuel race setup, then wondering why the alien times are out of reach: they were on a stripped qualy config.

Sharpen the balance and aero for peak, not survival

Because you only need one lap, run sharper rotation — more front end, a looser rear, more aggressive camber and toe — and the hottest power map available. Aero is track-dependent: trim a touch of wing for top speed where the lap rewards it, or add wing for cornering peak where it does not. You are buying grip you could never sustain over a stint.

Tire prep and the out lap

Slicks need one warm-up lap to reach their window before the flying lap. Scrubbing the tires (running a lap or two to clear the surface) brings them to temp faster at a small life cost — useful where you cannot overtake and want a clean shot. iRacing’s Qualifying Conduct Scrutiny tightens with license class (Permissive at Rookie up to Strict at B/A class) and penalizes tire-warming tricks like crawling the out lap, weaving, or failing to get up to speed; push it too far and you get a warning, then a penalty. It applies only to qualifying on asphalt tracks.

Race setup — built to repeat the lap

Hotlap times only matter in qualifying. Race pace and consistency win races, so the race setup trades raw peak for a car you can lean on every lap.

Full-stint fuel and ride height for a heavy tank

Compute fuel from consumption per lap times race length plus a margin, then carry it all. A heavy tank sits the car lower and makes it push early in the stint, so set ride height to clear bottoming on lap 1 yet still work as the car sheds the fuel weight toward the end.

Stability and tire life over raw peak

Bias the car slightly toward understeer so you can drive it hard without overworking the rears, and add a little wing for predictability. Set tire pressures to land in the hot window at the fuel load you will actually run — ACC GT3/GT2/GT4 targets roughly 26.0 to 27.0 psi hot post-v1.9 (the tighter GT3 band is 26.4 to 27.0 psi, and Coach Dave Academy quotes the current optimal band at 26.0 to 27.2 psi all-class), and a cold pressure tuned for qualy fuel will be wrong on a full race tank because the heavier car heats the tires differently over a longer run. Match cold pressure, fuel, and track temp to the session.

When you can’t change between sessions

Under parc fermé or a fixed-setup ruleset you race what you qualified on, often with only one or two adjustments allowed. Here the race compromise wins: a car that grabs pole but cooks its rears by lap 10 loses more than it gained. Set up for the stint, accept a slightly slower qualy, and finish.

Wet-weather setup — the changes that matter

Leaving a dry setup on in the rain overheats and pops the rear tires. The wet wants a different car.

Raise the car

Wet tires carry about double the tread depth and a larger overall diameter than slicks, which already lifts the chassis, and you want more clearance over standing water to resist aquaplaning. Raise ride height via the ride-height screen, packers, or stiffer springs as needed.

Soften the suspension

Soften springs, anti-roll bars, and dampers. A softer car puts more tire into the road and is more forgiving on a low-grip surface — see springs, dampers and anti-roll bars. At wet speeds you are nowhere near aero-relevant, so mechanical grip is what you are chasing.

Open the on-throttle diff

This is the one people get backwards. A tighter diff makes the inside rear spin and snaps the car loose on exit; opening the on-throttle lock lets the rear wheels turn at different speeds and keeps drive smooth. The common wet recipe in the F1 games drops the on-throttle diff well below its dry value. Open it, do not lock it.

Brake bias rearward, add wing, manage power

The fronts lock first in the wet, and the front tires clear water for the rears, so the rears have more grip than you expect — move brake bias rearward so you can brake harder without locking the fronts, and the heavier the rain the more rearward. Add wing front and rear for stability, balancing the extra rear against the front to keep the car neutral. Soften or raise TC and drop the engine power map where adjustable to manage wheelspin.

It’s a moving target

iRacing’s Tempest dynamic weather (2024 Season 2, March 2024) evolves through a session — a drying line forms, puddles shift — so the wet setup is never fixed. Forecasted weather rolls a chance of rain you cannot always plan for. Hustle the out lap to get heat in, then keep adjusting bias and diff as the track dries.

The dry baseline pages — springs, dampers and anti-roll bars, alignment, and brake bias — are the levers. This page is which way to move them for the session in front of you.