I have heard about this sport, but never watched it in person. While we were visiting Fernandina, Florida we drove by this park and I had to jump out to see this action. When I got up close I observed that a lot of the bikes had disc brakes with a shield on it. The shield was in place to prevent the rotor from being bent.I asked a player on the sidelines where the part came from. He told me some were custom made. all of the bikes looked like fixies with a flip-flop hub and disc brake on the front. I saw some amazing bike handling skills on the basketball, tennis court that was being used for the field of play.