The Swiss Army knife of trail bike tires: meet the Specialized Purgatory Grid Trail Tire. This do-it-all tread features large center square lugs that bite in soft soil, while still providing support on hard-packed ground and equally at home on the front or back of the bike. Block-in-block knobs rolls fast, adapt to terrain, but are supremely confident when pushed hard. There’s plenty of meat on the Purgatory’s carcass to offer reassuring grip across a wide range of terrain.