Published 3 November 2026 · OFM4x4.co.uk

An upsized tyre may look tougher while having an unsuitable marked load capacity. The sidewall code must be checked against the vehicle and the intended operating conditions.

The quick answer

Verify the tyre's marked load index and speed category against the vehicle's requirements, the relevant wheel and the planned load. Use the correct single- or dual-fitment context; do not infer capacity from tyre size alone.


Read the whole designation

Record size, construction, load index, speed symbol and any additional markings from the actual tyre. Two tyres with the same nominal dimensions may carry different indexes. Confirm the maker's current data rather than relying on a catalogue photograph.


Compare with the vehicle

Use the vehicle placard or handbook and permitted axle weights as the starting point. The MOT inspection manual includes load-index tables and minimum-requirement checks. A tyre with a higher number cannot make an overloaded axle legal.


Include the wheel and pressure

Confirm that the chosen rim width, load rating and fitting arrangement suit the tyre. Inflate to the vehicle or tyre manufacturer's instruction for the load and use; maximum sidewall pressure is not a universal everyday target.


Check mixed replacements

If only one axle is changed, verify the permitted size and construction combination for that vehicle. Different rolling circumferences can affect driven axles and vehicle systems. Ask a competent tyre specialist before mixing an alternative fitment.


Specification checklist

Before ordering or booking work, have these details ready: Registration, axle limits, existing and proposed full tyre markings, rim size/rating, and usual loaded use.


Frequently asked questions

Does a larger tyre automatically carry more?

No. The marked load index and the manufacturer's application data determine its rated capacity.

For an application check, contact OFM4x4.co.uk with the vehicle and component details above. Confirm the current fitting instructions for the exact product before work starts.

Technical reference: www.gov.uk. The relevant product manual takes priority over general guidance.