Track day tire pressures: cold vs hot, and how to actually dial them in

“What tire pressures should I run at a track day?” is the most common setup question in the paddock, and it has the least satisfying answer: it depends, and the number you actually care about is not the one you set. You set a cold pressure in the pits. The tire does its work hot. Get those two things straight and the rest of this is just method.

The number that matters is hot, not cold

A tire heats up as you drive it. The air inside expands, pressure rises, and the contact patch changes shape as it does. Grip, wear and feel all track the hot pressure — the pressure the tire is at while you are on track. The cold number you set in the paddock is only a means to land on the hot number you want.

So “what psi should I run” is unanswerable as a cold figure on its own. 32 psi cold means nothing until you know what it becomes after three hot laps. Two drivers can set the same cold pressure and end up 4 psi apart hot because one is on a cold morning and the other is in July.

Get the hot pressure right and the cold pressure is whatever gets you there in today’s conditions.

What hot pressure to aim for

There is no universal number, but there are sane starting points by tire type:

• Performance street / UHP tires (the tires most people show up on) usually feel best somewhere in the high 30s psi hot. Many drivers target around 36–40 psi hot and work from there.
• 200-treadwear semi-slicks (Bridgestone Potenza RE-71RS, Potenza Race, Yokohama A052, Nankang AR-1 and friends) are the one case where you should not guess: the manufacturer publishes a target hot pressure for track use, and it is often lower than you would run a street tire. Find that sheet and use it as your anchor.
• Full slicks run to the tire maker’s or series’ spec — out of scope here.

Whatever the tire, the target is the pressure where it feels planted and wears evenly across the tread. Too high and the tire crowns — it rides on the middle of the tread, grip goes greasy, and you will see wear concentrated in the centre. Too low and it rolls onto the outer shoulder, the sidewall flexes, the tire overheats and the steering goes vague. You are hunting for the pressure between those two.

(If you think in bar rather than psi, the same logic applies — roughly 0.2 bar per 3 psi. A car set to 2.7 bar cold is playing the same game, just on a different dial.)

How much pressure builds cold to hot

On track, a tire typically gains 3–6 psi from cold to hot over a session, sometimes more on the axle that is working hardest. That build is the whole reason cold and hot are different conversations.

So you set cold below your hot target by roughly the expected gain. Want ~38 psi hot on a tire that builds ~5? Start around 33 cold. Then you measure, and you adjust, because “roughly” is doing a lot of work in that sentence — the actual build depends on the tire, the track, how hard you drive and how hot the day is.

The loop that actually finds your numbers

This is the part nobody writes down and everybody re-derives from scratch every spring:

1. Set cold before the session — your best guess, or better, last time’s number in similar conditions.
2. Run the session.
3. Measure hot immediately when you come in. Pressure falls as the tire cools — a couple of psi in the first few minutes — so read it in the pit lane, not after you have parked and had a coffee.
4. Compare to target and adjust. Over your hot target? Bleed it down. Under? Add. Do it while the tire is hot if you are chasing a hot number.
5. Write down what cold gave you what hot, in these conditions.

Repeat until the hot pressure lands where you want it. Once it does, you have learned something worth keeping: this cold pressure, on this tire, at this track, in this weather, produces the hot pressure I want. That is a real starting point next time, instead of guessing from zero again.

Front vs rear — and why a GTI is not a Golf R

Pressures are rarely even corner to corner, and drivetrain is a big reason why.

A front-wheel-drive car works the fronts hardest — they steer, they put the power down, and they take most of the braking. Those tires heat and gain pressure faster than the rears, so a FWD car often needs a lower cold front to avoid overshooting the hot target up front. An all-wheel-drive or rear-drive car spreads the load differently and builds heat in a different pattern.

This is not abstract. A VW Golf GTI (FWD) and a Golf R (AWD) on the same tire at the same circuit will not want the same cold split — the GTI’s fronts run away with heat in a way the R’s do not. It is one of the things that shows up clearly once you have both cars’ pressures written down against the same track. (More on that specific comparison in a later post, once there is real data from both.)

There is no single magic number, because conditions move it

The reason “just tell me the psi” never gets a clean answer: the right cold pressure changes with ambient and track temperature. A cold spring morning and a hot summer afternoon need different cold sets to reach the same hot target, because the tire builds more heat and more pressure when the track is hot.

Same tire, same car, same corner — different day, different number. Which means the pressure you nailed last August is not the pressure you set this morning; it is the pressure you aim to end up at, adjusted for how the day is building.

Write them down, or re-learn them every season

Tire pressures are exactly the kind of data that is worthless in your head and valuable on a page. Cold and hot, per session, per tire set. Do it for a season and you stop guessing: “last July at this circuit, 33 cold gave me 38 hot on the Potenza Race and the car felt right” is a sentence you can only write if you logged it at the time.

This is the same argument as keeping a track day logbook instead of a spreadsheet — pressures are one of the first things that get lost when your notes live in four places. In ApexLog they sit on the session’s setup card, cold and hot, front and rear, next to the tire set they belong to and the laps you ran on them — so the number is there next year when the conditions repeat.

Try it on your own data

If you already import your laps from a RaceChrono .rcz, RaceChrono CSV v3 or RaceBox CSV, adding the cold and hot pressures for each session takes a few seconds in the paddock and turns into a reference you will actually use.

Start a logbook with ApexLog →

It is free to try, and logging one season of pressures is enough to see whether you ever want to guess at the track again.