Mountain Bike Tyre Guide

Overview

As your only contact point with the ground, the right mountain bike tyre can make a huge difference to your performance on the trail. With trail conditions varying in different locations and at different times of the year, choosing the best MTB tyre is not always obvious. In this MTB tyre guide, we break down the most important aspects, like tread pattern and tyre width to help you choose the perfect tyre for the trails that you love to ride.

MTB tyres are measured by their width alongside the size of the rim that it is designed to fit. See our tyre size guide to learn more about specific tyre sizing. The conventional wisdom is that wider tyres offer more grip, as they have a more rubber in contact with the ground, while narrower tyres roll quicker as there is less rolling resistance. While this is true for MTB wheel/tyre combinations that have the same diameter, mountain bikes are available with different wheel sizes. A 29er rolls significantly quicker than a bike with smaller 27.5” wheels if they have the same width tyres fitted. This means that we need to think about wheel size as well as tyre size. Our bike wheel size guide explains this in more detail.

Wider tyres have a larger volume which increases the overall diameter of the wheel. This means that the extra drag caused by the larger contact patch is offset by the increased speed offered by the larger diameter. This is why Plus sized tyres roll quickly despite their wide profile. One other thing to consider is that a narrower tyre will cut through mud to find grip while a wider one may tend to slide over it. This is why dedicated mud tyres are narrower than an equivalent tyre designed for rocky conditions.

The rubber on your tyres gives you grip by conforming to the lumps and bumps of the surface you are riding on. This means that a softer rubber compound will offer more grip than a harder compound. For the same reasons, a soft compound will be slower rolling than a hard compound. As with most things mountain bike related, there is always a compromise between speed and grip, so the ideal tyre compound will vary depending on the type of terrain you ride on. Soft compounds are preferable for downhill racing while harder compounds are a better choice for long distance cross-country rides.

Another thing to consider is durability. Soft rubber compounds wear considerably quicker than hard rubber compounds, especially in the centre of the tyre as it spends most time in contact with the ground. To take account of this, some premium tyres are made from multiple compounds, with harder compounds in the centre for improved durability and speed, and softer compounds on the side for improved cornering grip.

In an attempt to maximise grip and speed as well as longevity, some high-end tyres features special rubber compounds that combine synthetic materials with natural rubber, to improve grip and durability without negatively impacting rolling resistance. One of the best examples of this is Continental’s Black Chili compound which features nanometric carbon soot particles for improved all-round performance.

Mountain bike tyres need to be tough enough to cope with hard riding on challenging terrain. For this reason, mountain bike tyres are tougher than road tyres. Unfortunately making a tyre tough also makes it heavy. There is always a trade-off between weight and toughness. Cross-country race tyres are the lightest but are not recommended for anything other than racing due to a lack of durability. Downhill tyres are the toughest, with double thickness sidewalls to reduce the chance of getting a flat when the tyre pinches against the rim. These tyres are too heavy for efficient trail riding however.

In order to improve durability without adding too much weight, tyre manufacturers add tough abrasion resistant layers to their high-end tyres. Side walls are particularly vulnerable to cuts from rocks. Premium MTB trail tyres feature sidewalls reinforced with a lightweight abrasion resistant layer that protects the sidewalls of the tyres from cuts. Look for Specialized GRID, Schwalbe Evo, Continental Apex or Maxxis Exo tyres for the best side wall protection.

With their vastly improved puncture resistance, Tubeless tyres are fast becoming the norm on mountain bikes. When used with tubeless tyre sealant, small punctures will seal themselves without you noticing. Even larger punctures are easy to fix on the trail, as you don’t even need to take the wheel off the bike. See our tubeless repair video to learn how to repair a tubeless MTB tyre

Another advantage of tubeless tyres is that you can reliably run lower tyre pressures. This gives you more grip without the pinch puncture risk you get with inner tubes. While they take a little more effort to set up initially, this extra work is more than offset when you realise that punctures are almost a thing of the past. Converting to tubeless tyres is easy. Tubeless compatible tyres are often labelled ‘Tubeless Ready’.

Alongside wheel weight, tyre weight is probably the most important weight consideration on a bicycle. This is because of the rotational effect of the wheel which means that adding weight to the rim will slow you down more than adding weight anywhere else. You will notice the effect of a heavy tyre most climbing and accelerating, so is the first place to look when you want to make your bike lighter. The easiest way to reduce tyre weight without compromising performance is to choose a tyre with a folding bead. Folding tyres use a Kevlar bead instead of a traditional steel bead which is just as strong, but much lighter.

One of the simplest ways to improve the performance of your mountain bike is to ride with the right tyre pressure. The ideal tyre pressure will vary depending on riding style, rider weight, and trail surface. You want your tyres to be soft enough to conform to the lumps and bumps on the trail, but not so soft that you bang your rims on rocks and roots, or the tyre folds over and squirms about while cornering.

If you are riding cross country trails or a trail centre loop, then you will want your tyre to be hard enough for efficient rolling on the climbs but not so hard that you loose grip on the downhills. For aggressive downhill riding lower pressures are ideal as they will give you more grip. Downhill tyres tend to have thicker reinforced side walls that help to prevent pinch punctures and give you additional support while cornering. Another consideration is that a higher-volume tyre will require less pressure than a thinner tyre for optimal performance.

There are too many variables to give an ideal pressure range here, but most mountain bikers will run between 20psi and 40psi. Lighter riders will benefit from lower tyre pressures, while heavier bikers will need higher pressures to get the right level of support from the tyre. Mountain bikers tend to run a couple of psi more in the back than the front, as it is the rear tyre that takes the biggest hammering. A simple rule of thumb is never to exceed the recommended tyre pressure, found on the tyre side wall, but don’t be afraid to experiment with lower tyre pressures, especially if you are running a tubeless set-up. A digital pressure gauge or digital track pump is the most accurate way to measure tyre pressures, while a hand pump with a pressure gauge is the least accurate, but can be very helpful out on the trail.

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