Track day tyre pressures

By Sam Hayes

The short answer: most road-based cars want their tyres at roughly 30–34 psi measured hot, straight off the circuit — and the cold pressure you set in the morning is usually 4–8 psi below that, worked back for the day's temperature, your car's weight over each axle and how hard your circuit works each corner. Everything else on this page is the reasoning, the numbers by tyre type, and the questions the paddock actually asks. When you want the arithmetic done for your exact car, tyre and circuit, the calculator is free and works offline.

Recommended pressures by tyre type

Track pressures are targets for the tyre when hot. A session builds 4–8 psi over your cold setting (more if the tyre is overworked, less on a cool day or a short stint), so the hot number is the one that describes the tyre actually doing its job.

Ranges, not gospel: the right figure inside each range depends on the car's weight and distribution, the circuit's layout and the day. GripCalc carries 27 published manufacturer/series figures verbatim and estimates the rest from vehicle class and weight — each result is labelled with which it is. Racing typically targets 1–2 psi more than a track day, trading wear for response.

Set cold, verify hot, correct in the pit lane

Lower or higher than road pressures? Start lower. Circuit driving builds far more heat than any road drive, so the cold setting exists only to deliver the hot target once the tyre is worked. The gas law does the conversion (P₁/T₁ = P₂/T₂ on absolute scales), corner by corner, because a circuit never works four tyres equally — every layout in the circuit library carries starting figures for how much hotter each corner runs. Set the pressures with the tyres genuinely cold; a car driven twenty minutes to the airline has already warmed them.

After the first session, check hot pressures immediately: above target, bleed down; below, add air. That alone puts you ahead of most of the paddock. A probe pyrometer across the tread puts you ahead of the rest — the pattern of inner, middle and outer temperatures tells you whether the pressure (and the camber) is letting the whole contact patch work. The full method is published; the app just does the arithmetic faster than a cold thumb.

Choosing the tyre in the first place

What is the best tyre for a track day?

For a first track day: the good performance road tyres already on the car, at the right pressures — the limiting factor is seat time, not rubber. For regular track use, the sweet spot is the road-legal track tyre class (Michelin Pilot Sport Cup 2, Yokohama A052, Nankang AR-1, Toyo R888R): enormous dry grip once in their temperature window, durable enough for full days, and they drive home. Slicks are the fast answer and the expensive one — trailer, spare wheels, and no tolerance of rain. The honest order of lap time remains driver, pressures, then tyre.

Are track day tyres road legal? Can you drive them daily?

Most of that class is road legal in the UK and EU — E-marked, MOT-passing tread — but road legal is not all-conditions sensible. Below their working temperature the compound gives up a large fraction of its grip, the shallow tread clears water poorly, and they wear fast and run loud. As a daily they are a knowing compromise in summer and a poor idea in winter; full slicks and racing wets are not road legal at all.

The stickiest street tyres

The top of the road-legal pile — Cup 2 R, A052, AR-1, Goodyear Eagle F1 SuperSport R — reach friction coefficients around 1.2–1.4 in their window, against ~1.0 for a very good summer tyre. The catch is the phrase "in their window": the grip a tyre can generate is a function of temperature, and temperature is steered by pressure. A Cup 2 at the wrong pressure is slower than a summer tyre at the right one, which is why this site exists.

Asked at every track day

Should tyres be at 32 or 35 psi?

On the road: neither by default — the answer is the door placard, set by the manufacturer for your exact car and load, and it happens that most passenger cars land in the 32–35 band. The one adjustment worth making is temperature compensation: a pressure set in a warm garage reads low on a cold morning, which is what road mode restates for the day. On track, forget the placard and work from the hot target above.

Can I use 225-width tyres instead of 235?

Mechanically, usually yes — if your rim width supports the 225 and the overall rolling diameter stays within about 2% so the speedo and stability systems read true, and the load index still covers the car. You give up a little: at the same pressure the narrower tyre's contact patch is the same area but a longer, thinner shape that loads the rubber harder. Check your insurer's position before leaving the approved sizes.

Is 4/32 tread OK?

4/32 inch is about 3.2 mm — comfortably legal (the UK minimum is 1.6 mm) and fine for dry track work, where shallower tread means stiffer, cooler blocks. In the wet it is marginal: braking and aquaplaning performance fall away measurably below 3 mm, which is why many manufacturers recommend replacement there. For a wet track day, take the deeper set.

What is the "three-tyre rule"?

Not an official regulation. In US club racing it usually means a series limit on new tyres registered per event. Applied to road cars it is shorthand for tread matching: replace in axle pairs, keep the best pair on the rear, and don't run three fresh tyres with one worn one — a large front-to-rear tread mismatch changes the car's wet balance in ways you discover at the worst moment.

Which type of grip is best?

Trick question — you want both. Rubber grips by adhesion (bonding to the surface) and mechanical keying (flowing into its texture), and both mechanisms rise steeply with compound temperature. Every route to more grip — stickier compound, wider tyre, more load — runs through keeping the tread in its temperature window, and the tool for that is pressure. Which brings the whole page back to one instruction: set cold, verify hot, measure everything.