Look up the KG capacity for any tyre load index, or find the minimum load index required for your vehicle's gross weight.
The load index is printed on the tyre sidewall after the size (e.g. 205/55R16 91V)
per tyre
The GVW can be found on the vehicle's VIN plate or in the owner's manual
for a kg vehicle (kg per tyre)
The load index is a numerical code on the tyre sidewall that indicates the maximum weight each tyre can safely support when correctly inflated. For example, a tyre marked 205/55R16 91V has a load index of 91, meaning it can carry up to 615kg.
It is critical that the load index of your tyres meets or exceeds the requirements for your vehicle. The total load capacity of all four tyres combined must be equal to or greater than the Gross Vehicle Weight (GVW), which includes the vehicle's kerb weight plus passengers, luggage, and any payload.
Running tyres with an insufficient load rating is dangerous. Under-rated tyres can overheat, deform, and fail catastrophically at speed. This is especially important when fitting aftermarket alloy wheels, as the replacement tyres may have a different size and therefore a different load index.
Always check the load index when changing tyre sizes, and never fit tyres with a lower load rating than specified by the vehicle manufacturer.