August 25, 2020

What Are Tires Made Of?

What are tires made of? Many would answer the question with a kneejerk reaction: rubber. But the truth is a bit more complicated because tire material can include everything from nylon chords to tough steel wire to silica to sulfur. The typical composition of your average car tire goes far beyond rubber. Tire shoppers may not know about the arduous and complicated process of creating tires out of many complicated materials when they buy tires online, but this quick intro can help illuminate how layered a car or truck tire is.

Trying Out New Sources for Natural Rubber

What are car tires made of?

Today, tires are not made of rubber entirely, but a mix of chemicals and materials combined for optimal performance. Only about a third the composition of a tire is natural rubber, with textiles, fillers and cables making up the weight.

So, what materials are tires made of? Here’s a list of “ingredients”:

  • Natural Rubber
  • Butyl Rubber (Synthetic)
  • Polybutadiene Rubber (Synthetic)
  • Styrene-Butadiene Rubber (Synthetic)
  • Halogenated Polyisobutylene Rubber (Synthetic)
  • Steel Wire
  • Polyester Fabric
  • Nylon Fabric
  • Rayon Fabric
  • Aramid Fabric
  • Silica Filler
  • Carbon Black Filler
  • Natural Fillers (Such as Cornstarch or Wood Pulp)
  • Antioxidants
  • Antiozonants
  • Zinc Oxide
  • Sulfur

What are the main layers of a tire?

Why are there so many different types of materials in a tire? The type of materials used often depends on the layer. This is what a typical car tire composition looks like:

  • Bead: The bead wraps around your car’s rim and secures your tire to the rim, so it needs to be extra strong. It typically contains a ribbon-like cable that is frequently made of steel and coated in rubber. One might not think there would be metal inside a tire, but there is!
  • Inner-liner: This innermost part of the tire structure is meant to hold air inside the tire, and typically is made of a synthetic rubber.
  • Plies: The body ply of the tire usually has several layers of different materials, often with cords to add strength to the tire. These cords are made of fabric materials like polyester, nylon, or rayon.
  • Belts: Belts are the layer between the cords of the ply layer and the tread. These layers add strength to the tread and help to absorb shock.
  • Tread: This part of the tire directly touches the road, and is generally the part featured in your typical tire commercial. There are many, many different types and designs, but they’re usually carved in a way to avoid hydroplaning and grip the road.
  • Sidewall: The side of the tire needs to be both tough and flexible, and is typically made of rubber, though some also feature nylon inserts or even steel.

How much natural rubber is in tires?

Natural rubber, which is made from latex sap that’s taken from several different types of rubber trees (such as the Amazonian rubber tree and the Congo rubber tree) comprises only about 28 percent of a conventional car tire by weight. For trucks, it’s usually somewhere between 19 and 34 percent. Collecting the sap for rubber is monotonous, difficult work; trees need to be sapped every day for about two decades. Companies like Bridgestone looking to lower their carbon footprint (many synthetic rubbers require petroleum) in the midst of natural rubber trees becoming more scarce are in a bind, so many are trying out new sources for natural rubber, like dandelions.

Answering the question of “What are tires made out of?” may raise even more questions about which tires are right for your car. Feel free to connect with us to ask questions about the composition of the tires you’re planning to buy.

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