Understand your tyre pressure results

What the numbers in the Apex Tyre Calculator result mean — the per-corner grid, the target hot pressure, and the calculation breakdown.

After you select Calculate Pressure on the Tyres page (sidebar → Tyres), a Pressure Readout appears. This article explains each part so you know exactly what to set on your tyres.

The per-corner grid

The readout shows a 2×2 grid, one box per tyre:

• Outside Front and Inside Front (the two front tyres)
• Outside Rear and Inside Rear (the two rear tyres)

Each box shows a nominal pressure in large gold text (in PSI) — this is the cold pressure to set — with a smaller low – high range beneath it. "Outside" and "Inside" refer to the tyres on the outside and inside of the corners, which is why they can differ depending on the track Direction.

Target Hot Pressure

Below the grid is a single Target Hot Pressure range. This is what your tyres should rise to once they're hot and working on track. It's higher than the cold figures because tyre pressure climbs as the rubber heats up. Set the cold pressures from the grid, then check the tyres reach roughly this hot range when you're up to speed.

The calculation breakdown

Three small figures explain how the numbers were built:

• Base PSI — the tyre's starting pressure before adjustments.
• Temp Adj. — how much was added or removed for the track temperature.
• Modifier Total — the combined change for your other choices (grip, session, driving style, and so on).

If you turned on the 6-Step toggle, you'll also see a 6-Step Adjustment section with a Baseline range, an Adjusted range, and each step's contribution.

Tips

• Set tyres to the nominal (gold) cold figure for each corner; use the low–high range to fine-tune.
• A higher Track Temperature raises the recommended pressure — that's normal physics (warm gas expands).
• If the numbers look high, check whether you're reading the Target Hot Pressure rather than the cold per-corner figures.

Frequently asked questions

What does "nominal" pressure mean? It's the single recommended cold pressure — the middle of the suggested range — shown in large gold text for each corner.

Why are the inside and outside tyres different? The kart leans on the outside tyres through corners, so the calculator can suggest slightly different pressures for the inside and outside, depending on the track Direction.

The pressure seems too high — is something wrong? Probably not. Check you're not reading the Target Hot Pressure (which is always higher than cold) and that your Track Temperature is correct — a hot track raises the recommended pressure.

What units are the pressures in? PSI (pounds per square inch). As a guide, 1 PSI is about 0.069 bar or 6.89 kPa.