Seismic Alpha Wheels 80.5mm x 55mm 78A set of 4. 80.5mm tall x 55mm wide LDP Trim: Optimal balance of momentum, efficiency, and grip for pushing and pumping speeds! A highly-optimized balance of properties for modern racing. The fastest urethane that the skateboard industry has ever seen, bar none. The largest and most supportive hub ever seen in a wheel this size. Size and momentum to carry you past the competition in straightaways, yet agile enough for quick acceleration, fast edge-to-edge adjustments, and snappy technical pre-drifts. Finely-calibrated width and supremely supported edges for smooth, predictable handling through even the hardest corners.