In areas of extended high ambient temperature, vehicle tyres can be affected by a softening of the tyre's sidewall. If the vehicle is stationary for long periods, the tyre deforms at the point where the standing surface meets the tyre.
The tyre deformation described is known as a flat spot and is normal tyre behaviour.
When the vehicle is subsequently driven, a vibration may be experienced from the flat spot. The condition steadily improves with extra mileage.
In order to minimise flat spotting, increase the tyre pressures to the maximum, as stated on the tyre's sidewall. The tyres must be returned to the specified running pressures before driving. See TYRE PRESSURES and TYRE MARKINGS.