Tyre size calculator

Tyre load index table

Load indicates the maximum load capacity at which a tyre can be safely operated, subject to the tyre being in sound condition, correctly fitted and with the recommended inflation pressure. See table below for load index and the maximum load per tyre.

Typical load index examples (per tyre at the correct pressure):

• 88 ≈ 560 kg
• 91 ≈ 615 kg
• 94 ≈ 670 kg
• 100 ≈ 800 kg
• 104 ≈ 900 kg

Under‑specifying the load index is a safety risk. If the tyre’s load index is too low for the vehicle, the tyre can overheat, deform, and wear prematurely. Over‑loading any tyre or running too low a pressure increases heat build‑up and the chance of failure. Ensure the combined load capacity of the tyres on each axle meets or exceeds the vehicle’s gross axle load limits. When comparing options, consult a tyre load rating chart to verify that the tyre load rating you select is appropriate for your vehicle and usage.

Start with your owner’s manual and the tyre placard, usually found on the driver’s door jamb, fuel flap, or glovebox. These list approved sizes and the minimum speed and load ratings for your vehicle. Select tyres that meet or exceed these specifications. Matching the tyre speed and load rating to your vehicle helps preserve safety and compliance.

Match your tyres to how you drive:

• Daily commuting and highway use: Choose a speed rating suitable for posted limits and sustained cruising in Australian conditions. Maintaining the specified rating supports stability and braking at motorway speeds.
  
  
• Towing and heavy loads: Prioritise a higher tyre load rating and consider light truck (LT) constructions where recommended. Confirm that the tyre load capacity aligns with your towball download and axle loads.
  
  
• Off‑road or mixed use: Select tyres with robust constructions and appropriate load capacities for gravel, corrugations, and unsealed surfaces, while still complying with the placard.
  
  
• Performance driving: Higher speed ratings can help preserve handling precision and heat resistance, particularly for vehicles with sport suspension and larger brakes.

Fitting tyres with ratings below the manufacturer’s specification can compromise safety, accelerate wear, and may affect roadworthiness or insurance. Matching or modestly exceeding original equipment ratings helps preserve handling, braking, and durability without unnecessary impact on ride comfort. If you’re comparing several options, use a tyre load rating chart to make sure the tyre load rating you choose suits your vehicle’s axle limits and intended loads.