Whereas a motorcycle helmet would bear an M rating. The SA rating requires the helmet to pass flammability and rollbar impact tests, while the M rated helmets do not have to pass those tests.

That said, the eyeport may not be an wider for an SA rated helmet.

Personally I drive with a full face helmet, visor up, and wear safety glasses (I keep clear ones and sunglass ones in my track bag). If you think an HPDE is hot, try doing an enduro stint with a full fire suit, gloves, balaclava, etc, that's hot!

• Snell Memorial Foundation

Car long since sold. Sig is for historical purposes only.