Tire Tread

Tires are the most critical, but also the most overlooked, component of a vehicles ability to move. A vehicle can technically still move forward with no engine in place, the engine is the propelling mechanism, while the tires are what allows the vehicle to be propelled. Sadly, at AAMCO we often notice cars running on tires half flat, trucks with little to no tread left, and even some that have foolishly driven on tires that have begun to fray. If you are in need of a tire repair, please check out what AAMCO locations

Unlike other parts to a vehicle, the only sign that a tire is going to fail is a visual one. No check tire lights come on (yet at least), so in order to know whether your tires are safe to drive on, you have to visually inspect them. You always see in movies and on TV someone walk over and kick the tires to ensure they’re good to go. Oddly though, unlike The Fonz, most people cannot hit something into working. Rather than strike the tire to ensure it’s resilient, you should be looking at the depth of the tread and ensure it hasn’t worn away, that the tire is properly inflated, and that there are no obvious signs of wear and tear. There is no need to kick the tire… unless of course it goes flat. You can kick a flat tire all you want, maybe, just maybe… you can pull a Fonz.

But our lack of concern over tires may simply be a result of our lack of knowledge on the subject. So to help clarify what comprises and makes a tire a tire, rather than a wheel, we are going to discuss treads. As a wheel can basically be anything round or circular used for various purposes. While a tire is specifically for vehicles, and what makes a tire different from a wheel is tread.

Tire Tread

The tread is the part of the tire that comes into contact with the ground. They are often designed to meet specific market demands either for certain weather conditions or for certain types of performances. The tread is either made of a rubber or rubber/composite, while the the tread itself is characterized by four geometrical shapes; Grooves, Lugs, Voids, and Sipes.


Grooves are designed to channel water away from under the tire. There are various types of grooves depending on the need. High performance tires have grooves that are angles from the center of the tire out towards the sides. Which helps to flush the water out from underneath. There are even certain grooves in tires that flex as the tire moves, which acts as a pump for the water, sucking it up into the groove, channeling it out towards the side.


Lugs are the part of the tread that actually makes contact to the ground, they are needed to provide traction. The lug, as it runs over the ground is compressed. As the tire continues, the lug returns to its normal shape. Amid this process, the tire releases variable forces in the vehicle which are referred to as Force Variation. Force Variation is essentially a fancy phrase to say that the tire is continually changing shape as it moves, but always returning to its normal figure. The Lugs themselves are also never identical in size or shape to help minimize the noise levels.


Voids are there to provide space for the lugs to shift and flex. They also help the grooves to disperse water from under the tire, as well as mud and snow. The void ratio is the space between lugs, the lower the void ratio the higher the contact area, the higher the void ratio the less the contact area.


Sipes are the cuts across the tire that run perpendicular to the grooves. They help the grooves to allow water to escape from the center of the tire toward the sides which allows the tire to maintain traction and prevent hydroplaning. The Sipes also are also helpful to the Lugs, by allowing more space for them to flex.

Hopefully this article will help to shed some light on how tire tread helps to keep you safe on the road. If you are in need of a car tune up or a transmission repair please visit your local AAMCO dealer. AAMCO is now offering a free transmission check for those who feel it is needed. Because those who know, know to go to AAMCO!