http://www.reocities.com/TelevisionCity/network/3070/history.htm

The 1970s
Skateboard Heyday
Was the 1970s
By Eric “Arab” Groff

The 1970s is still considered by many to be the glory days of skateboarding. Every kid on the block had a board and skateparks were everywhere, with the first park being Carlsbad Skatepark in Southern California. Much of skateboardings growth would not have been possible if it wasnt for a man named Frank Nasworthy, who single-handedly changed skateboarding forever with the creation of the Cadillac Urethane skateboard wheel. This new product set the stage for skateboards to go above and beyond where they had been before with pool riding, downhill slalom, pipes, ramps, parks and sidewalks… Skateboarding had become accessible and effortless for everyone.
Although there were other advancements in skateboard design like kicktails, wide trucks, 10 inch boards, radial wheels and precision bearings, Nasworthys wheels would prove to be the greatest invention and contribution to skateboarding. (and you can quote me on that).