Mountain bike tyres are characterised by the knobbly tread patterns required to gain traction off-road. Replacement MTB tyres for wet and muddy tracks will feature large, widely-spaced knobs for grip, compared to smoother, closer-spaced tread for dry trails. MTB tyres also offer different rubber compounds, with softer compounds offering better grip and traction but a faster rate of wear. Tyres will also differ in terms of sizing, with models to suit the various MTB wheel standards (26”, 27.5” and 29”). Tyre width can also vary. MTB tyres are also available in tubeless versions, which in combination with compatible rims offer an airtight seal.