Chris S

What's worse are the double-hoop style bars that offer no rollover protection but could act as mousetraps in the event of a rollover. I hate those things. They look ugly, too.

CG

I had a 90 Mata as a track toy with a Kirk Racing 5pt. competition roll bar in it. I was rear ended by a Camry going 55 to 60 mph faster than I was. The rear of the car folded up to the point that the bar was bolted into the frame. I believe the bar saved me from worse injury. I'm only 5'8" so the headrest protected my head so I didn't hit the well padded roll bar. If I had been taller I'm not sure the padding could have saved me from a cracked Melon. However, I would not have a Miata without a good bar installed.

rockville

I suspect the fact that the body stopped crumpling when it got to the roll bar is probably not because of the roll bar. Instead it's probably because that's the same area where the gas take happens to sit. Mazda is willing to let your luggage get crunched to save your life but they, likely wisely, decided that it was a good idea to not use the fuel tank as part of the crush space. Also if you look at the legs of the typical bar they are not well setup for resisting the crushing loads you are talking about. From the side the roll bar looks a bit like a wishbone. Strong for vertical loads but the two legs are only tied together by the stock chassis.

TougeS2k

CG

In general I agree. The crumple zone worked well and I my first thought was that the roll bar did little to help in this type of crash. When I took it apart afterwards I was surprised to see how the bending stopped at the rear bolt in point of the bar. While there was some slight bending in front of the oversized "feet" at the rear of the bar there was a sharp cut off of the primary frame deformation that was clearly, in my mind at least, due to the change in rigidity of the non-typical Kirk bar. I have however occasionally wondered if the bar may have added a little too much stiffness resulting in the crush space not being allowed to protect the passenger compartment to the fullest. However, maybe just because it makes me feel better to believe it, I will stick with my initial assessment that it protected me.

One other thought since you brought up the vertical loads which the bar is intended for. Just before the girl hit me she nailed her brakes. As her nose dived she somehow scooped me up and folded the back of my car under. My back bumper was rolled under to the point that it had tire tracks from my tires on the painted surface. A great deal of the impact was absorbed axel back underneath. Maybe the roll bar took something of a vertical load from the bottom instead of the top as would normally be expected. (?)

David1

When you get run over by a Peterbuilt semi in it, roll bars will not matter.

RC 94

Yay ridiculous examples.

Chris S

I recorded 1.91G in my last Miata via my TraqMate. Anyone who thinks they're incapable of much speed or grip is sadly mistaken.

JonBoy

Sarcasm meter broken, Chris?

CosmosMpower

That had to be a peak spike, not sustained cornering?