Understanding the Components of Commercial Truck Tires

Modern commercial truck tires are actually more complicated than many people realize.  They’ve been engineered over the decades to stand up to incredible pressure, while still being able to travel for tens of thousands of miles before needing to be replaced or retreaded.

Much of that is due to their construction, so in today’s blog, our team at STTC wanted to briefly talk about how commercial truck tires are built and how each layer of the tire adds to its overall performance.

Understanding the Seven Key Parts of a Truck Tire

1. The Inner Liner

The innermost part of the tire is a liner which is primarily designed to hold in the tire’s air.  It’s composed of synthetic rubber specifically created for strength and longevity.  (In fact, up to 70% of a modern commercial truck tire is synthetic rubber.)

2. Carcass 

The carcass is a layer of cords which create a semi-rigid frame around the inner liner, helping the compressed air within retain its shape.  The carcass will also largely determine optimal tire pressure and the overall amount of load the tire can handle.

3. Bead

The bead is a thin layer of wire, steel, and rubber which directly bonds the tire to the rim.  It also provides some structural support, further helping maintain the tire’s shape.

4. Sidewall

The sidewall is one of the most critical components.  Made of flexible crack-resistant rubber, it’s located between the bead and the outer tread, and is there to protect the carcass – and the inner liner – from damage.

5. Belts (also called Breakers)

Belts are made from steel cords which are embedded into rubber and connect the tread to the carcass.  Belts’ primary purpose is binding the tire’s layers together, but it also provides some protection from puncture.

6. Undertread

The undertread is a layer of rubber made from synthetic and natural rubber. This layer helps keep the tire cooler when driving and it is necessary when retreading a tire. The undertread is the rubber layer that the retread rubber bonds to.

7. Tread

Finally, the outermost layer is the tread – the part of the truck tire which touches the road.  It’s generally made of a blend of both natural and synthetic rubber and is the thickest rubber on the tire.

Turn to STTC For Top Quality Commercial Truck Tires

We have decades of experience providing commercial truck tires for vehicles of all sizes.  Visit any of our locations for assistance!