Tire Pressure Load Adjustment
Get a guideline tire pressure adjustment for heavy loads — enter your placard pressure, baseline load, and current load.
Tyre Pressure Load Calculator
Placard + load change → suggested pressure
How It Works
Tyre load and pressure are proportionally related — a heavier vehicle needs more pressure to maintain the same contact patch and prevent overheating. This tool provides a proportional guideline; always verify with your tyre’s load-inflation tables.
How to Use This Calculator
- Find the placard pressure from the door jamb sticker.
- Estimate the baseline load the placard was set for (typically GCW or typical occupancy).
- Weigh or estimate your actual current load (passengers + cargo + tow tongue weight).
- Click Calculate — a guideline adjusted pressure appears.
- Never exceed the maximum pressure printed on the tyre sidewall.
Worked Example
Reference Table
| Load Factor | Pressure Adjustment | Ride Quality | Notes |
|---|---|---|---|
| 0.8× (lightly loaded) | −3 to −5 PSI | Softer | Slight comfort improvement, marginal |
| 1.0× (normal) | As placard | Designed optimum | Baseline setting |
| 1.1× (loaded) | + 2–3 PSI | Slightly firmer | Good for sustained highway |
| 1.2× (heavy) | + 4–6 PSI | Firmer | Near-maximum typical passenger load |
| 1.3× (near GVWR) | + 6–8 PSI | Hard | Approaching tyre limits — check load index |
Frequently Asked Questions
Can I use one pressure for all load conditions?
Not ideally. Over-inflated tyres when lightly loaded cause accelerated centre-tread wear and harsher ride. Under-inflated under heavy load causes tyre overheating and potential blowout. Adjust to match actual load conditions.
Do I need to check tyre load index when changing tyre sizes?
Yes — the load index (e.g., 91 = 615 kg per tyre) must meet or exceed the vehicle’s requirements. Your four tyres combined must be able to carry the vehicle’s GVWR. Never fit tyres with a lower load index than specified.
Why does tyre pressure affect fuel economy?
Tyres flex as they roll — under-inflated tyres flex more, generating heat and rolling resistance. Correct inflation reduces rolling resistance by 0.5–1.0%, improving fuel economy. Running 10 PSI low on all four tyres can reduce economy by 0.3–0.6%.
What is the recommended tyre check frequency?
Check pressure monthly and before any long trip (when tyres are cold). Temperature changes of 10°C alter pressure by approximately 1 PSI. Winter pressure drops are common and often overlooked.
