TYRE CASINGS
Single-ply, high-tpi
The thinnest MTB tyre casings are built for cross-country (XC) riding and racing. Key objectives are low weight, great acceleration and minimal rolling resistance, but they must also be able to cope with varied terrain without tearing or puncturing. Tyres with a lightweight casing like this generally have a low-profile, fast-rolling tread pattern and are usually 2.4in wide or narrower. The high thread count of a 120tpi tyre means less material overall, resulting in a lower overall weight, which is vital for all-out acceleration, but at the expense of some durability.
Single-ply, medium-tpi
Most tyres for everyday riding use a 60tpi casing. This makes them slightly heavier than a high-tpi single-ply tyre, but the thicker threads make them stronger and sturdier, without being overly heavy, so they’re suitable for everything from XC and downcountry to trail and enduro. Manufacturers often combine a single 60tpi ply with a puncture protection layer in the sidewall (eg. Maxxis’s EXO Protection casing, Schwalbe’s Apex) for added structural support and resistance to cuts and pinch flats, or even a bead-to-bead puncture layer (eg. WTB’s SG2 system), both options being lighter than speccing a dualply (two layers of material) carcass.
Dual-ply, medium-tpi
For gravity-fed riding – especially bike park laps and downhill (DH) racing – you need a really sturdy tyre that can withstand massive forces, including ripping around bermed turns and hitting rock gardens flat-out. Tyres in this category normally use a dual-ply 60tpi casing and sometimes have additional sidewall puncture protection, too. The heavy-duty construction and increased rubber volume mean these beefy tyres also tend to be better at damping trail vibrations, so they bounce less over bumps and give a more planted ride. Two layers of 60tpi material is regarded as su cient for slamming through corners and smashing into rocks, while remaining manageable in terms of weight. These tyres are significantly heavier than the other options, though, and the tough casing is usually paired with a softer-compound tread, so they roll significantly slower. Of course, this isn’t a big problem when you’re pointing straight down the hill.
Dual-ply, high-tpi
Some brands o er dual-ply 120tpi tyres for really aggressive trail riding or enduro racing. The idea is that these provide good support in the turns and against big hits, but with a higher rolling speed and lower weight than a 60tpi equivalent. Maxxis’s DoubleDown, Schwalbe’s Super Gravity and Vittoria’s Enduro casings are all examples.