Tire management on track

iRacing models two tire temperatures, and the gap between them explains almost everything you feel: tire core and tire surface. Surface temp rises almost instantly from braking, sliding, or weaving. Core temp is what actually gives you grip, and it takes a full lap or two of sustained load to come up. When core and surface are far apart, the tire is slippery — cold core early in a stint, or pinned-red surface late in one. Keep the two in line and the car does what you ask.

Warming tires: what works and what doesn’t

You cannot fake core temp. Heat into the core comes from sustained load — cornering forces working the carcass — plus heat radiating out of the brake disc. Surface tricks only touch the surface.

Does weaving on the out lap work?

Mostly no. Weaving on the formation or out lap is about 90% placebo for core temp because you can’t load a tire hard enough at out-lap speeds to heat the carcass. Weaving does bump surface temp a little, which buys marginal first-corner confidence, and it risks picking up marbles and debris off-line. If you want real heat into the tire before turn one, drag the brakes: iRacing models heat radiating from the brake disc into the tire and wheel, which raises core temp. It works, but at full throttle it burns noticeably more fuel — a real cost in open-setup and endurance racing. Hard, deliberate braking warms tires more effectively than light dragging.

If you have the laps, scrub the tires — run one or two laps to clear the outer surface and bring everything up to temp. A scrubbed set reaches grip faster for a quicker out lap, at a slight cost to ultimate life. That trade is worth it for an undercut on a track where passing is hard.

The first three laps

Cold tires are why you’re slow on lap 1-3, not the car. Tires come up to temp by lap 3-4, and you also get faster as fuel burns off and the car lightens. The modern GT3 and GTP/hypercar tire models take longer to reach optimal temp and are extremely slippery when cold. Hypercars are heavily downforce-dependent, so you genuinely need a few laps before you can lean on them.

Drive accordingly for the first laps: smooth inputs, no sudden steering or throttle jabs, no trail braking, brake in a straight line. Don’t ask the tire for grip it doesn’t have yet. See braking technique for how trail braking changes once the tires are in.

The cliff: what it is and how to recognize it

Grip doesn’t fade in a straight line. It holds, degrades gradually, then drops sharply once the tire wears or overheats past a threshold — lap times fall off a cliff. You recognize it by feel: the rear steps out on corner exit, understeer shows up that wasn’t there earlier, surface temps pin in the red, and the slide no longer “comes back” when you wait for it.

The fix on track is simple. Back off 2-3 tenths, lift earlier, get the surface temp out of the red, and let the tire recover what it can. Pushing through the cliff only digs the hole deeper.

Driving style that extends a stint

Overdriving is the number one cause of fast deg and of understeer. If you’re understeering, you’re overdriving the car — asking the front for more than it has, scrubbing temp and rubber into the surface. Slow down and you go faster as a result, because the tire stays in its window for the whole run. Take proper care of a set and you can double-stint it, which is the foundation of pit strategy in long races.

Concrete habits that save tires:

• Feather the throttle on exit instead of mashing it; wheelspin is heat and wear you don’t get back.
• Coast more into corners and use less on/off brake — smooth, single brake applications rather than stabs.
• Stay out of the ABS on cars that have it; on older models the surface temp spikes the moment ABS engages.
• Mind lockups. On the current iRacing model a lockup spikes wear and surface temp but does not model a flat spot. It still costs grip and rubber the moment the tire stops rotating, so treat it as wear even without the vibration of a flat spot. LMU, by contrast, does punish a lockup with a flat spot until your next stop.

For oval tire saving, DJ Yee-J’s videos are the standard reference — the short version is feather the throttle, coast, and avoid on/off brake to keep the rears alive.

By sim

• iRacing runs the core/surface model described above. The 2024+ GT3 and GTP cars are slower to warm and very slippery cold. Note that iRacing AI doesn’t simulate tire temperature — AI tires sit at optimal temp and wear slower than yours, which is why they can feel faster on old rubber.
• Le Mans Ultimate and Assetto Corsa Competizione behave similarly: prototypes and downforce cars need temperature before they reward aggression.
• Automobilista 2 is more forgiving on warmup but still punishes overdriving over a stint.

Reading the tire HUD

The dash tire blocks show surface temp by color: blue is cold, green is optimal, red is overheated. The number under each block is pressure (blue means under, red means over), and the bar shows wear. Use the color to confirm what your hands already told you — if the blocks are red and the car is sliding, you’re past the window, not under it.

See tire pressures and temps for setting cold pressures so the surface lands green at speed.