As you may know, the NHRA safety rules, which govern the NMCA, require a Snell SA-certified helmet that comes with an expiration date. Every five years the Snell Foundation increases the standards to improve racer safety, and the certification is named by the release date (e.g. SA2005, SA2010, SA2015). What you may not know is that your helmet is not necessarily out of date when the new standard i...