While there\u2019s a lot to consider when eyeing up a fresh set of boots for a mountain bike, including compound, width and tread pattern, the carcass \u2013 also called the casing \u2013 is at the core of any bicycle tyre.<\/p>\n
Selecting the right tyre for your needs can seem like a confusing web of jargon and brand bluster \u2013 and, truth be told, even the most experienced riders can still become lost in the naming conventions and technical specifications of any range of tyres.<\/p>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>But fear not, BikeRadar is here to help.<\/p>\n
While every brand will have its own jargon, the same construction principles apply. Get to grips with the way tyre carcasses are constructed \u2013 and what that means for your ride \u2013 and you\u2019ll soon understand how to choose the best tyres for your riding.<\/p>\n
There\u2019s a lot to cover here, so use the links below to skip to the section you need, or read on for every detail.<\/p>\n
- Dissecting a mountain bike tyre<\/a><\/li>\n
- Why does carcass construction matter?<\/a><\/li>\n
- What types of mountain bike tyre carcass are there?<\/a><\/li>\n
- What mountain bike tyre carcass do you need?<\/a><\/li>\n
- What else is there to consider?<\/a><\/li>\n<\/ul>
Dissecting a mountain bike tyre<\/h2>\n
![\""Maxxis\"]( "\\"\"Maxxis\\"\/")
<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>The construction of a typical mountain bike tyre will look like this.<\/span><\/figcaption> Maxxis<\/strong><\/a><\/span><\/div>\n Let\u2019s start with an overview of how a typical mountain bike tyre is constructed, as well as the common terminology.<\/p>\n
A mountain bike tyre is made up of many layers, but most tyres from the majority of manufacturers are designed in a similar way. The above image from Maxxis shows a regular mountain bike tyre\u2019s construction with its composite parts:<\/p>\n
- Bead:<\/strong> A wire or rubber section that hooks onto the rim, keeping the tyre attached to the rim and creating an air-tight seal.<\/li>\n
- Carcass (often referred to as the \u2018casing\u2019):<\/strong> This part is what this article is all about. A casing can be thick or thin with a low or high TPI (we\u2019ll come on to this). The casing can wrap around itself once or multiple times, and wraps around the tyre\u2019s bead.<\/li>\n
- Tread:<\/strong> Defining the type of terrain or riding style the tyre is most suited to, the tread pattern of different tyres can vary greatly, but its form isn\u2019t generally influenced by the casing.<\/li>\n
- Puncture protection:<\/strong> A rubberised insert used within the tyre\u2019s construction to provide protection against tears or pinch flats. Increased puncture protection adds weight.<\/li>\n
- Sidewall:<\/strong> The rubberised exterior of the tyre that gives it shape. The sidewall is usually where some of the puncture protection portion is located (for example Maxxis\u2019 EXO or DoubleDown inserts).<\/li>\n<\/ul>
Why does carcass type matter?<\/h2>\n
A tyre\u2019s carcass can have a significant influence on how your bike rides, according to Aaron Chamberlain from Maxxis.<\/p>\n
A tyre with a thicker casing creates a \u201cmore damped ride, which is typically desirable\u2026 [when] you\u2019re smashing into rocks and roots at high speeds and subjecting the tyres to high cornering forces,\u201d he says.<\/p>\n
Heavy-duty models might be great for stability in turns and for damping vibrations and bumps, and can often be run at lower pressures, but they\u2019ll weigh more and create more rolling resistance (drag).<\/p>\n
On the other hand, a thin, lightweight carcass can improve acceleration, deform around smaller, sharper bumps more readily and roll fast \u2013 but it might be more prone to punctures, or tear more easily, and sometimes require higher pressures.<\/p>\n
![\""Male\"]( "\\"\"Ribble\\"\/")
<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>Tyre carcass construction can have an impact on how your bike rides.<\/span><\/figcaption> Andy Lloyd \/ Immediate Media<\/i><\/span><\/div>\n According to Schwalbe\u2019s Tim Ward, lighter, thinner carcasses can also \u201creduce trail buzz and, in turn, rider fatigue, allowing the rider to put all their energy into [riding].\u201d<\/p>\n
Tyre carcasses that sit between these two extremes are designed to balance the damping and stability of weighty tyres with the compliance and deformation of lighter ones.<\/p>\n
This, according to Ward, \u201cenhances the rolling characteristics and trail feedback\u201d while offering \u201cincreased lateral support and stability in hard cornering.\u201d<\/p>\n
Although tyre carcasses aren\u2019t a silver-bullet solution for improving or changing the way your bike rides, they can have a significant effect, and choosing the right tyre for your needs is crucial.<\/p>\n
With that in mind, let\u2019s get stuck into the different types of mountain bike tyre casing construction.<\/p>\n
What types of mountain bike tyre carcass are there?<\/h2>\n
![\""YT\"]( "\\"\"YT\\"\/")
<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>Confused by what all this means? We\u2019re here to help.<\/span><\/figcaption> Steve Behr \/ Immediate Media<\/i><\/span><\/div>\n In this article, we will focus on mountain bike-specific carcasses, where there are typically more options available from the major brands.<\/p>\n
Gravel tyres<\/a>, road bike tyres<\/a> and general-use bicycle tyres use the same principles of construction, but have different objectives (eg, low cost or all-out rolling performance) and there are fewer carcass types to choose from.<\/p>\n
What is tyre carcass TPI?<\/h4>\n
A mountain bike tyre carcass consists of layers, starting with and always including a rubberised threaded material that forms the basis of all tyres \u2013 each layer that makes up the construction of the carcass is referred to as a \u2018ply\u2019 in tyre jargon.<\/p>\n
A tyre\u2019s carcass material is made from threads of varying thickness and quantity, usually 60 or 120 threads per inch (TPI), that are coated with rubber.<\/p>\n
A lower TPI means thicker, stiffer, heavier threads, thus fewer per square inch. A higher TPI means thinner threads that will create a lighter, more flexible tyre with thinner sidewalls.<\/p>\n
The thicker the threads, the more rubber is needed to fill the larger spaces between each one, as they can\u2019t be woven as tightly.<\/p>\n
As a result, carcass construction can affect the weight, rolling resistance, damping, reliability and grip of a tyre.<\/p>\n
Many mountain bike tyres use a single-ply or dual-ply 60 TPI casing material to create a well-supported, resilient tyre; others might use only a single layer (or \u2018single ply\u2019) of 120 TPI material for lighter weight and increased flexibility, which helps reduce rolling resistance on rough ground.<\/p>\n
Puncture-resistant inserts or sidewall inserts aimed at providing extra support and stability may also be added as additional layers within a casing, but these vary from brand to brand.<\/p>\n
<\/p><\/div> <\/section>
Selecting the right tyre carcass is often about the riding discipline.<\/p>\n
Downhill and cross-country riding, for example, place different demands on tyres: stable and sturdy for downhill bikes<\/a>, light and fast-rolling for cross-country bikes<\/a>.<\/p>\n
It can also come down to the rider (heavier or more aggressive riders might favour stability over rolling resistance) and the terrain (an XC racer<\/a> might not necessarily choose the lightest, fastest-rolling tyre if the terrain is rocky and likely to damage the tyre sidewall).<\/p>\n
Generally speaking, there are four types of carcass construction, each outlined below.<\/p>\n
The devil really is in the detail, though, as some tyre brands offer casings with the same name but in two different constructions (for example, 60 TPI and 120 TPI), which will have an impact on the tyre\u2019s performance and intended use.<\/p>\n
Single-ply, high-TPI carcass<\/h3>\n
![\""Maxxis\"]( "\\"\"Maxxis\\"\/")
<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>The EXO casing from Maxxis is an example of a single-ply carcass designed for low weight and fast-rolling speed, with some protection against punctures.<\/span><\/figcaption> David Arthur \/ Immediate Media<\/i><\/span><\/div>\n A 120 TPI single-ply tyre favours speed over durability.<\/p>\n
The thinnest mountain bike tyre casings are built for XC-style riding and racing. The key objectives are low weight, fast acceleration and minimal rolling resistance, but they must also be able to cope with the varied terrain of modern XC courses<\/a> without tearing or puncturing.<\/p>\n
Tyres with a lightweight casing generally have a low-profile, fast-rolling tread pattern and are usually 2.4in and narrower in width.<\/p>\n
- Carcass (often referred to as the \u2018casing\u2019):<\/strong> This part is what this article is all about. A casing can be thick or thin with a low or high TPI (we\u2019ll come on to this). The casing can wrap around itself once or multiple times, and wraps around the tyre\u2019s bead.<\/li>\n
- Why does carcass construction matter?<\/a><\/li>\n
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