Tyre pressures

But what happens if you over or under inflate your car’s tyres?

Over inflated tyres:

  • Have a smaller contact patch with the road
  • Will decrease rolling resistance and could therefore improve fuel consumption
  • There may be an effect on braking
  • Tyre wear may be greater in the centre of the contact area
  • Compromise handling, ride comfort and tyre noise

Under inflated tyres

  • Under inflated tyres have a greater contact area with the road
  • This can increase rolling resistance and friction (the rubbing together of two moving objects) from tyre against road.
  • Increased friction is bad for overall efficiency, and increases fuel consumption
  • Can also create greater tyre wear and adversely affect performance. Increased friction causes tyres to get hotter, and the shape of under inflated tyres means that the shoulder of the tread wears faster
  • Put extra stress on the casing and reduce tyre life
  • Will adversely effect braking performance


Clearly checking tyre pressure and making sure it is at the recommended level is of benefit to your pocket and overall safety and driving enjoyment.