Q: What Happens if I Overinflate My Tires?

Inflating tires to the correct pressure is one of the most important factors when inflating a tire. Both under and, over-inflating a tire can actually be detrimental to the performance of a vehicle and to the life of a tire.

When you over-inflate a tire, the air pressure inside the tire is increased and pushes on the inner walls of the tire with increased pressure. This increase in pressure causes along the insides of the tire causes the it to become stiffer than normal, taking away from its performance and affecting the overall performance of the vehicle in a number of ways.

Over-inflating tires causes the sidewalls and tread of the tire to become harder than normal. This can reduce the traction and performance of the tire, as well as cause uneven tire wear. When the pressure is increased beyond the recommended pressure, the contact patch of the tire actually shrinks. The increased pressure causes the center of the tread to protrude further out than the rest of the tire tread. This is a problem because now the majority of the tire’s traction is coming from only the center of the tire, reducing the overall contact patch of the entire vehicle. This is also why overly-inflated tires show signs of uneven wear along the center. Over-inflated tires will show signs of accelerated wear along the center, because the center is making more contact with the road than the outside edges are. This same decrease in contact surface can also cause a drop in mpg, as the engine now has to work harder to compensate for the reduced contact patch.

Over inflating tires can not only be detrimental to the performance characteristics of a vehicle, it can also take away from the comfort and safety of the vehicle as well. Overly-inflated tires will also cause the vehicle to have a harsher, more unstable ride than properly inflated ones. Tire sidewalls are meant to support the vehicle as well as absorb some of the shocks and bumps from the road’s surface as the vehicle drives over it. When the tire is overly-inflated the sidewalls become harder, and instead of absorbing the road bumps and shocks, they are transferred straight through to the vehicle’s suspension. This can result in a harsher ride, as well as increased road noise from the tires. In severe cases, when dealing with older or severely overinflated tires, the tire’s sidewall may even be put at risk to blowing out due to the increased pressure.

It is generally recommended that the tire’s on a vehicle always be inflated to the proper manufacturer’s suggested pressure, and never past maximum pressure indicated on the sidewalls. Keeping the tires at the suggested pressure, as well as rotating them at regular intervals, is the best way to ensure that you get the best performance as well as the longest life out of your tires.