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SM Roll Cage Design and Construction

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#1
smscca

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Hello Everyone

I would like to introduce a topic for discussion that I have not seen discussed on the forums in quite a while. The SM racing program has some of the best production car racers, chassis specialists and engineers in motorsports and I am anxious to read the replies to this question.

How important is the design and construction of the roll cage in a Spec Miata to the overall handling characteristics of the race car?

#2
Scottie

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I am not an expert. But my car was on 3 jack stands yesterday (I had 4 under the car, but one wasnt adjusted up all the way). It was perfectly flat. So, it obviously adds rigidity, which MAY make for a better handling car. I would say yes.
How do I fit this Ls7 into my mia.... nevermind

#3
Kyle Burkhardt

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Any cage is going to add that kind of rigidity and, therefore, improve handling. I think OP's question is whether there is a better design cage. I'm no expert either, but there won't be a great difference between SM cages since you can't tie in the shock towers. What you can do is consider weight. Make it as light as the rules and your sense of personal safety allow. Also, ideally you would want to tie the bars into the body, but that's not legal, so a good builder will get the bars to touch the body (ex the A pillar bars, the front roof bar touching the top of the windshield frame, the hoop touching the sides, etc) which does a pretty good job of accomplishing the same thing.
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#4
davew

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Every cage builder has their own prefernces. I prefer my design and can explain why. But not here, the question is not about that.

I have driven lots of these cars over the years. I have not noticed a significant difference in cornering with cage design. What I have noticed is in braking. A well designed cage ( this refers to not only my design, but also any of the major cage builders designs.)just stops better. More consistent and more stable.

Do not let the cage touch the a-pillar. Unless you have a deal for free windshields. The movement of the windshield frame will cause the windshield to crack.

Dave

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#5
Kyle Burkhardt

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Makes sense about the windshield. I come from the tin top world.
Kyle Burkhardt
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#6
Bruce Wilson

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The guy that built his SM with some of the bars made of exhaust tubing thought that lower COG was more important than rigidity. Gotta wonder if he was correct, a complete moron, or both? :o

Safety first!

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