You might think of bike tires as an essential but pretty straightforward piece of equipment. They’re circular, rubber, and made to grip the road or trail, right? Well, yeah. But there’s a bit more to know about tire design. Here, we’ll give you the full story on bike tire technology, including things like puncture resistance, casing, beads, and TPI (threads per inch). Whether you’re riding road, trail, or path, this knowledge will help you make the right choice when it’s time to upgrade your tires with a replacement set.

Bike tire anatomy

1 Bike tire casing

The casing is the foundation upon which the tire tread sits. It’s constructed from many threads that are tightly woven together. The standard of measurement for a casing’s quality is its TPI—threads per inch—or the number of threads contained in one inch of the tire casing.

2 Bike tire bead

The edge of the tire that fits into the rim is call the tire bead. There are two main types of beads, and they’re often referred to as wire bead and folding bead. Wire beads are heavier and generally found on less expensive tires. Folding beads, which are often made from aramid fibers, are lightweight and often found on performance tires. Aramid is essentially a super strong and durable synthetic polymer.

3 Puncture protection

Some higher-performance tires, and especially road and hybrid tires, feature built-in puncture protection. These “breaker belts”, as they’re known, help provide extra durablity.

4 Bike tire tread

The tread is the part of the tire which contacts the ground. Some tread is designed to roll in a specific direction in order to offer the most efficiency, longevity, speed, and traction. If the tire is directional, the sidewall will have an arrow pointing to the proper tread direction the tire tread is meant to roll forward.

Tire technologies explained

What’s a tire’s TPI and why does it matter?

The standard of measurement for a casing’s quality is its TPI—threads per inch—or the number of threads contained in one inch of the tire casing. The higher the TPI, the higher the number of threads per inch, which makes the tire lighter, more supple, and delivers better road or trail feel and performance. For example, a higher TPI tire like 120tpi is going to offer a more supple, responsive, and comfortable ride than a 60tpi tire.

What is a bike tire compound?

Bike tire compounds are the specific material makeup of the tire tread where the rubber meets the road. Compounds are optimized for best performance based on their intended use and location. For example, the center tread’s compound maybe optimized for longevity, while the softer rubber compounds on the sides are designed to allow the tire to conform to the ground for the best traction.

What is bike tire durometer?

Durometer is a measure of how soft or how hard the rubber is. The lower the number, the softer the rubber. Tires with a lower durometer offer more traction, but generally roll slower and will wear more quickly. Tires with higher durometers are more rigid, and will generally last longer, but not provide quite as much grip. Some tires have dual compounds that use a softer rubber on the sides for cornering traction and and a harder rubber in the center for tread life and a faster rolling speed.

What is tire siping?

When riding in wet conditions, a tire with siping helps with traction. Tire siping allows water to channel into grooves built into the rubber tread. The grooves help push the water out away from the tire to ensure the rubber stays in contact with the pavement to retain grip and traction.

Bike tires vs. bike tubes

Bike tires are what you see attached to the wheel while the inner tube is hidden inside the tire and is what holds the air. If you get a flat tire, it is important to check the tire for any large cuts that may require a new tire, otherwise it is quite common to only have to replace the inner tube. Also, make sure to look for the cause of the flat—such as a nail or piece of glass—and remove it from the tire before you replace the inner tube. If you don't, you could get another flat!

What about tubeless?

As the name implies, tubeless tires are designed to be used without tubes. When you pair a tubeless tire with tubeless-ready wheels, sealant, tubeless valves, and a tubeless rim strip, you’ll no longer need to use a tube. There are a lot of benefits to tubeless tires — far fewer flats and the ability to run lower pressure for better traction, to name just a couple. Plus, they’re easy to set up. If you’re considering tubeless, make sure you choose a tubeless-ready (TLR) tire and wheelset.

Learn more about tubeless

Top picks for city tires

Best-recommended road tires

Rider-endorsed gravel tires

Fan-favorite mountain tires