The Tioga Powerblock is the ultimate BMX racing tyre, designed to efficiently transfer pedal power and other rider inputs into lateral motion. In short, you’ll roll faster with less wasted energy. In steel bead with thicker, stronger sidewall. The standard Power Block strikes the sacred equilibrium between performance and value. The outer knobs About half the length of the transition knobs, the outer knobs are designed for maximum compression and traction at lean angles greater than 25 degrees. Typically not needed during a clean race, but if things get messy, the outer knobs will keep tracking during aggressive manoeuvring and cornering giving you every last bit of grip to get you across the finish line faster. The centre row "Power Block"During acceleration, heavy pedalling torque is transferred to the centre tread zone of the rear tyre. If these centre knobs are too small or tall they will exhibit greater knob flex/compression and stick to the ground just a bit longer before take-off, robbing valuable energy (too much traction is not always a good thing) conversely if knobs are too big or short, the tyre may slip under heavy torque before regaining traction significantly slowing you down. The transition knobs Substantially smaller than the centre blocks and in exact proportion to the centre blocks the transition knobs are designed to deform slightly at lean angles greater than 15 degrees. This knob deformation or compression is the rubber "sticking" to the ground which is akin to traction. They are positioned at 45 degree angle relative to the centre knobs to help maintain forward momentum during side-to-side transitions and cornering.