How to choose your MTB tyres

Your tyres are the first and only thing that connects you to the ground. It's also your first shock absorber!
Alas too often neglected by beginners, tyres are essential elements of your bike. The choice of MTB tyres affects comfort, traction, performance, but also safety. It's necessary to know them well in order to make the most of their possibilities.

The dimensions of a MTB tyre

You will commonly encounter dimensions in this form, for example: 26 x 1.95"
26 "is the diameter in inches of your wheel and 1.95" is the width of your tyre.
If the diameter is normalized (in adult MTBs, the wheels are 26", 27.5" or 29 "inches in diameter), this isn't the case for the tyre section.
Sometimes tyres of 1.75 are as wide as 1.95 tyres, the latter of which are larger than 2.10.
The tyre's cut varies according to the brand because there is no standardisation at this level.
The most common sizes are between 1.40 and 2.60, which covers just about every possible use.

ETRTO, got it?

For more precision in your research, please refer to another indication printed on your tyre named: ETRTO (European Tyre and Rim Technical Organisation). This indication has been controlled and standardized,and is indicated in millimetres in this form: 50-559 50 corresponds to 50 mm of width at the level of the studs, while 559 corresponds to 559 mm in diameter.

MTB Tyres 26"

MTB Tyres 27,5"

MTB Tyres 29"

Casing

It is made of nylon or more-or-less woven cotton threads. Some are thick and stiff, others thinner, tighter, more supple and more expensive.
In mountain biking, flexible casing offers more latitude of deformation to the tyre. Thus you will get greater motricity and comfort by absorbing shocks.
The figure that determines casing flexibility is indicated by the TPI number, a measure indicating the number of yarns per inch (1 inch = 2.5 cm). Above 100 TPI, the casing is very flexible and the tyre considered a high-end one.

Tread and beads

The tread covering the casing is composed of a mixture of rubber and other chemical ingredients (such as silica) that affect density, rolling resistance, mud adhesion to the rubber, wear and physical aspect.
Today, some treads are more or less hard depending on the area of the tyre. For example, there may be a difference between the tread and the sidewall (bi-density, triple compound, etc.) so as to optimize grip and performance without adversely affecting output.

The beads: these are the two hoops that press the tyre against the rim.

Rigid beads are made of steel wire. They are intended for heavier entry-level tyres or tyres that need to be perfectly maintained on the rim (trial or downhill tyres, etc.) despite low operating pressures.

Foldable beads are made of aramid or para-amid, including kevlar, and are intended for high-end tyres. Noticeably lighter, they have the advantages of being easy to assemble and store thanks to the possibility of bending the tyre.

The tyre beads on the Tubeless and Tubeless Ready tyre models are specific to guarantee the water tightness of both rim and tyre.

Tyre technology

All brands offer innovative solutions that continuously integrate new technologies.
It's sometimes difficult for the average customer to make sense of so many rapid changes.
In order to facilitate your choice, we have listed all the technologies for each brand.

Pressure

The air pressure in the MTB tyre affects its dynamic characteristics. Smaller cross-sectional tyres should be more inflated than large cross-sections ones to avoid pinching and the subsequent puncture. Keep in mind that over-inflation reduces grip, traction and comfort by favouring performance on smooth terrain.
On the contrary, by deflating, comfort as well as grimp improve because the surface in contact with the ground is superior. On the other hand, this induces a higher rolling resistance, and therefore a reduced output.

You have several solutions to inflate your tyres: the foot pump, the hand pump, the CO2 inflator...

knobs

The role of a rear tyre is to promote traction. For this purpose, it's usually equipped with aggressive knobs on the tread. These are often perpendicular to the rolling direction in order to bite the ground (they are square, round or diamond-shaped). The knobs are smaller if the ground is dry and the tyre is designed to promote performance.
The front wheel is the steering wheel: precision and grip in curves mostly relies on it. For this reason, the stud will be more aggressive, in the form of directional arrows, and more pronounced on the tyre's sidewalls (the area in contact with the ground, when the bike is in a slip angle).

Choose according to your practice:

Enduro - All-moutain

Section around 2.35", aggressive lateral knobs but round profile to retain an advantageous yield.

DH - Downhill

Large section with aggressive, well-shouldered side knobs for maximum cornering grip, and solid center pads to resist bending caused by heavy braking.

XC - Cross Country

XC Rolling : thin and fairly low knobs, a medium section and an often-lightened casing for minimum weight and maximum performance. For dry and rolling trails only. From 1.90 "to 2.15".

XC Dry : more volume for better shock absorption. Double or triple density gum and prominent side knobs for a more efficient grip.

Mud

Section between 2.0 "and 2.2", medium spaced knobs for excellent grip in all conditions.

Tubeless MTB

All the motor sports praise the Tubeless pneumatic technology which has in turn invested the MTB. Hutchinson and Michelin worked with Mavic to popularize the system in 1998-99. The tubeless tyre has no inner tube.
The pneumatic envelope and the rim form a watertight ensemble thanks to specific tyre treads whose continuous ribs are integrally molded into the rim of the tyre.
The rim itself must be completely watertight. Some are specifically designed for this purpose, while others can be transformed into Tubeless via a specific assembly.

Tubeless tyres reduce the risk of puncture by pinching (cutting the air chamber between the obstacle and the rim) and makes it possible to roll with lower pressures.
Some tyres called Tubeless Ready were later developed to gain in weight by retaining the tubeless beads so that the tyre can be clipped on the rim. However, this system imposes the use of preventive fluid to waterproof the tyre's carcass, which is lightened and closer to a Tubetype carcass (inner tube).

To sum it up:

Tubetype: inner tube assembly.
TL ready or Tubeless Ready: tubeless assembly (without inner tube) with tyre sealant.
Tubeless: Tubeless assembly (without inner tube).

Practitioners' tips:

Versatile tyres: a sound investment

Schwalbe Nobby nic

Maxxis Crossmark

Hutchinson Cougar

Michelin Wildgrip'r

The tyre design allows for traction and performance, and offers rubber and tyre reinforcements of varied quality to balance puncture resistance and the MTB tyres' weight.