Two figures with different purposes
A sidewall may show a maximum pressure or a pressure associated with load capacity. This belongs to the tyre's technical limits. It is not automatically the recommendation for the vehicle currently using it. The same tyre can have different vehicle instructions in different approved applications.
Use the appropriate cold-pressure instruction from the vehicle manufacturer or confirmed wheel-and-tyre combination. It is often on a placard or in the handbook. A special fitment needs its corresponding instruction established.
Consider loading and axle position
A vehicle may specify different front and rear values and different loading conditions. Read the relevant row completely. Do not mistake a temporary-spare value for the normal wheels. A photograph of the whole table is more useful for an enquiry than one isolated number.
Units matter too. Bar, kPa and psi do not have identical numerical values. Use a clearly labelled gauge or reliable conversion rather than rounding by instinct to a familiar-looking figure.
Do not invent a maximum or midpoint target
Do not inflate everything to the sidewall maximum as a precaution. Equally, averaging two conflicting instructions does not automatically produce the right answer. Have unclear applications identified professionally. Tyre, wheel and valve must suit the intended conditions.
Pressure measured after driving may be higher than the cold reading. Do not simply release air to bring a warm reading down to the cold target. Follow the checking and adjustment instructions and investigate unusual changes.
Keep a confirmed reference
Record the correct source for your combination and load. This avoids guessing between sidewall numbers at the next air station. If wheels or use change, check whether the reference still applies.
Repeated loss is not explained adequately by frequent topping up. Have the cause assessed. The maximum figure says nothing about why air escapes or whether the tyre remains sound after driving with pressure loss. Tell the workshop about that history rather than reporting only the last reading.
