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The load index corresponds to a capacity under specified conditions. Index 91, for example, has a table value of 615 kilograms. It does not mean the tyre carries 91 kilograms. Use an appropriate reliable table rather than estimating values from neighbouring codes.
Capacity is not independent of pressure, speed and application. Looking only at the table value can miss important conditions. Selection therefore needs to bring together vehicle requirements and the tyre's actual construction.
Why total weight divided by four is insufficient
Axle loads can differ. Specific vehicle and tyre requirements may also go beyond a simple calculation. Use the approved specification or have an alternative professionally confirmed. A higher index does not permit exceeding maximum vehicle mass or axle load.
Commercial tyres may show multiple indices for different arrangements. These numbers are not options chosen by preference. The actual single or twin application must be identified. Ask before ordering if a listing shortens this information.
Distinguish similar offers
A tyre model may be offered in one nominal size with several load indices. XL or HL suffixes can matter here. Compare complete specifications rather than the model name alone. A cheaper result with insufficient capacity is not an equivalent offer.
Check the speed rating and other suffixes too. Changing wheels requires consideration of the complete combination. A tyre's load index does not establish the wheel's own capacity.
Keep the confirmation
Have an unclear application answered using the vehicle data and precise tyre description. Keep that answer with the invoice. It supports future replacement and prevents an incomplete number being passed to another workshop.
If conversion or frequent heavy loading changes the use, reconsider the vehicle limits. A suitable tyre marking replaces neither weighing when uncertain nor compliance with those limits. It is one technical part of suitability, not general permission to add cargo. Ensure everyone loading the vehicle understands that distinction, especially when a replacement tyre has a larger number than the previous set.
