We will require SA 2005 or better rated helmets for MINI Thunder IV. Please check your helmets to be sure they qualify. They should have a sticker inside. If you don't have one you can rent them at Thunderhill from the track for $35/day. Here is a website that helps explain the SA vs. SM (Motorcycle) ratings Ratings: Auto Racing Helmet Ratings - RacingHelmetGuide.com Sources for new Helmets: Auto Racing Helmets http://www.thebellstore.com/ - Speedway Motors, America's Oldest Speed Shop