Roll Cage Requirements in HPDE?

[Del Armstrong]

I’ve done a couple of HPDE events now, and am having a blast with it. But it’s come to my attention that the roll bar in my Miata convertible has an issue. With my helmet on, my head is taller than the roll bar. :eek: This is clearly unacceptable, and I appreciate the folks who pointed out the problem.

I'm having problems finding the NASA rule which specifies what the requirements are for clearance between the helmet and the roll bar. Is there such a rule, or is it a judgment call? I've seen references on the net to 2" between the top of the helmet and the "broom stick", but I can't find anything official in the CCR. Does anyone know what the requirements are (and if they're written somewhere, where I can find them)?

It looks like neither a taller roll bar, or a lower seat will buy me 2” of clearance. However I might be able to use the car with the removable hard top installed. Does having the hard top on mitigate the roll bar problem for HPDE? I’ve seen comments that in spec Miata the hard top must be “permanently” installed. Does permanent mean welded on, or just bolted on (so I can remove it when I want to)?

So to summarize, what is the minimum clearance I need? Can a removable hard top fix the problem? And if a hard top will work, how does it need to be mounted?

Thanks.

Del

[ker]

del, sorry i didn't see your email until i saw this as well.

there is no "rule" that requires your helmet to be below the roll bar (which is why you are allowed on the track). however, you should do whatever you can to get under. i think the reason for the 2" you've heard of is most likely if the car is upside down you will hang in your straps and "fall" some.

[Del Armstrong]

Kevin,

Thanks for your reply, that really helps. I'll see what I can do to improve the situation as much as I can.

Del