Due to demand for a racing version of our Tarantula 70mm wheel, Tunnel offers a Tarantula with an extremely high-rebound racing urethane that maximizes speed and grip.The “STR” – Speed Through Research - urethane formula optimizes the performance of the off-set, 70 mm wheels. In other words, these wheels are fast!Tunnel and AEND Industries created the new urethane, and Longboard Larry and his racers as well as Canada’s Lee Cation did testing and added input.The Racing Tarantulas are poured in 78A STR racing urethane with an eye-grabbing red and black swirl. Look for more color combos in the near future.