mcsinc wrote:Does this include the roll hoops in the S2000 and MX-5?
M helmet is fine with factory roll over protection. If the factory protection is padded enough to protect your fleshy melon in a street crash then it's soft enough for an M helmet.
The rules actually say M helmets aren't legal with a roll cage. However, I don't see where the rules provide a definition of when a roll bar becomes a cage. In fact the two terms seem to be interchanged in various places. The point is though that an M helmet isn't designed to sustain multiple hard impacts such as might occur from an unprotected bar right behind/beside your head.
Basically by definition an M helmet is for motorcycles, but is legal for autocross. Motorcycle helmets are typically designed to sustain one major impact while SA and above are for motorsports and designed for multiple impacts, fire protection, etc
There is this reference to padding on roll bars though.
J. ROLL BAR PADDING
i) Braces and portions of the main hoop subject to contact by the driver’s or passenger’s
helmet, as seated normally and restrained by a seatbelt or harness, must be padded with a
non-resilient material such as Ethafoam(R) or Ensolite® or other similar materials with a
minimum thickness of 0.5 inch