You might think of bike tyres 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 tyre design. Here, we’ll give you the full story on bike tyre 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 tyres with a replacement set.

Bike tire anatomy

1 Bike tyre casing

The casing is the foundation upon which the tyre 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 tyre casing.

2 Bike tyre bead

The edge of the tyre that fits into the rim is call the tyre 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 tyres. Folding beads, which are often made from aramid fibres, are lightweight and often found on performance tyres. Aramid is essentially a super strong and durable synthetic polymer.

3 Puncture protection

Some higher-performance tyres, and especially road and hybrid tyres, feature built-in puncture protection. These 'breaker belts', as they’re known, help provide extra durability.

4 Bike tyre tread

The tread is the part of the tyre 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 tyre is directional, the sidewall will have an arrow pointing to the proper tread direction the tyre tread is meant to roll forwards.

Tire technologies explained

What’s a tyre’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 tyre casing. The higher the TPI, the higher the number of threads per inch, which makes the tyre lighter, more supple, and delivers better road or trail feel and performance. For example, a higher TPI tyre like 120 tpi is going to offer a more supple, responsive and comfortable ride than a 60 tpi tyre.

What is a bike tyre compound?

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

What is bike tyre durometer?

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

What is tyre siping?

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

Bike tyres vs bike tubes

Bike tyres are what you see attached to the wheel while the inner tube is hidden inside the tyre and is what holds the air. If you get a flat tyre, it is important to check the tyre for any large cuts that may require a new tyre, 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 tyre before you replace the inner tube. If you don't, you could get another flat!

What about tubeless?

As the name implies, tubeless tyres are designed to be used without tubes. When you pair a tubeless tyre 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 tyres – far fewer flats and the ability to run lower pressure for better traction, to name just a few. Plus, they’re easy to set up. If you’re considering tubeless, make sure that you choose a tubeless-ready (TLR) tyre and wheel set.

Learn more about tubeless

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