There is an official system, it's the Riders Only section of AMAProRacing.comAMA PR SM Pit Steward said:
Licensed racers, crew, team owners, and other AMA credential holders are able to contact AMA regarding such things as rule changes, etc. In any proposed rulebook change, riders et al have a comment period prior to implementation. Seemed to me to be nothing more than lip service to say Pro Racing was doing something for the riders, but that's another story.....
As far as a publicly voiced "suggestion box" goes, this is most definitely the place to do it. If you get many responses, perhaps you could categorize them, and present them in order of importance to the powers that be. Good luck, and thanks for the help.
