Properly Inflated Tires Save You Fuel

Did you know that your vehicle will use 2-4% less fuel just by having your tires inflated properly? The Energy Conservation Center in Japan did a study that found exactly that!

Because the tires on most passenger cars lose 5-10% of their air pressure every month, I recommend checking the air pressure in your tires on a monthly basis to ensure that you stay safe, and save money on fuel.

It’s good for the environment too!

Inflating Your Tires Properly Will Make Them Last Longer

What’s more, if your tires don’t have the proper PSI then they will wear unevenly. Not only is this a safety concern, it’ll force you to replace your tires more often (and cost you money). A worst case scenario is that improperly inflated tires could burst.

Generally, if your tires are under-inflated the shoulders (outside edges of the tire) will wear down faster than the middle of the tread. If your tires are over-inflated the center of the tread will wear down faster than the rest of the tread. 

How Do I Know What PSI value is Right for my Tires?

If you aren’t sure, you can stop at any tire center and a technician will be able to help you out, but generally inside the driver’s side door you’ll find a sticker with the recommended inflation pressure. Your tire may have it printed on the sidewall as well.

Just remember that when checking the pressure in your tires, do so on a cold tire that has been parked a while to get an accurate measurement.

Tires have come a long way, and today’s tires are safer than they have ever been before. There are nine basic parts of modern passenger tires, and I’ll list them below so you have a sense for how your vehicle’s tires are constructed (and why they’re built that way).

The Tire Tread

A tire’s treads are there to grip the road, improve water displacement and drainage, assist with vehicle performance (turning, braking, and cornering), and they also protect the belt and carcass of the tire to ensure it lasts longer.

Most tire treads are made from a layer of rubber suitable to how the tire will be used.

For example snow tires will use a rubber that remains soft in colder weather.

Other tires may use firmer rubber that is better suited to driving on hot summer roads).

Tire Shoulder

The widest part of the tread on either ouside edge, which rounds over into the sidewall of the tire. A tire’s shoulders aid with dispersing heat, and protect the belt and carcass of the tire. Generally the same rubber as the rest of the tread.

Tire Belt

Typically made of iron or other metal compounds, the belt is a strong, rigid layer beneath the tread which reinforces the tire and improves the stiffness of the tread to enhance tire performance and durability.

The Tire’s Bead

On the inside edge of a tire’s sidewall, the bead of a tire anchors it to the wheel and supports the sides of the tire. Within a tire’s bead are:

Bead Wire

Usually made of several strong steel wires which reinforce the material within the bead and help maintain good contact with the vehicle’s wheel when inflated.

Bead Filler

A tire’s bead is filled with a rubber compound which is triangular in shape. This improves the stiffness of the bead and is used to help maintain good contact between the tire and the wheel when inflated.

A Tire’s Inner Liner

The interior of your vehicle’s tires are coated with a special type of rubber that mitigates air migration. This helps your tires stay inflated and maintain pressure.

Tire Carcass

Every tire needs to support the weight of the car above it, and the carcass is the body of the tire that bears this load. On most modern tires the carcass is a layer of rubber coated fabric laid into the tire in a radial direction designed to support load and absorb impact.

The Side Wall of Your Tire

Each side of the tire has a vertical wall that runs between the tire’s shoulder and bead. The thick rubber coating of your tire’s sidewall protects the carcass of the tire and deflects debris and obstacles during operation. This is a really important part of the tire in terms of its integrity, which is why damage to a tire’s sidewall will usually result in replacement.

Every tire has a set of numbers on the sidewall which include the tire’s size code. On this blog I’ll explain how to read these numbers (and which ones you need to know to order new tires in the right size for your vehicle).

But right now let’s take a look at the 5 key measurements of a tire:

• Total Width – This is the total measurement of your tire from sidewall to sidewall when properly inflated to the recommended PSI, and mounted on your vehicle. It includes any decorations and/or protective ribs.
• Section Width (W) – Similar to the total width, the section width differs slightly. It’s a measurement of your tire’s width from sidewall to sidewall when properly inflated and mounted, but without load placed on the tire. It also differs in that this measurement excludes any decorations or protected ribs that are on the tire’s sidewall.
• Section Height (H) – This measurement refers to the vertical distance between the outer tread’s surface and the bead seat of the tire when properly inflated and mounted. The measurement should be taken with no load placed on the tire.
• Inside Tire Diameter (Rim Diameter) – Measured in either inches or millimeters, the rim diameter of your tire is the distance between tire bead seats measured at the widest point of the tire.
• Outside Diameter of the Tire – This is simply the distance between your tire’s tread measured at the widest point of the tire. The measurement is taken with the tire mounted, but with no load applied to the tire.