Z3 1990 Miata
#42
Just ran a sim on 4 point bar traditional style with a main hoop using 1.5OD and 0.12 wall with 75ksi yield strength(TuffDOM) regular DOM 1020 steel is about 60ksi. using same 3000lb loads I got this.
not any stronger but about 10lb lighter due to superior strength compared to 35ksi I used for no brand bar.
not any stronger but about 10lb lighter due to superior strength compared to 35ksi I used for no brand bar.
#46
Cpt. Slow
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You still haven't come CLOSE to matching an actual roll bar or it's mounting points. Much less come close to real life forces.
If you're so hell bent on using FEA, you need to be doing stress tests on rolled over miata roll bars, not guessing by the weight of the miata.
#48
Hard Dog Hard Bar Sport - Polished Stainless Steel
That's what I used for second bar. I used same loads for comparative analysis only.
Anything I say or prove doesn't matter because everyone is going on "Nobody does this bias".
That's what I used for second bar. I used same loads for comparative analysis only.
Anything I say or prove doesn't matter because everyone is going on "Nobody does this bias".
#49
SADFab Destructive Testing Engineer
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I would be more worried about the material than the structure of the bar. Is it really 1/8 inch thick tubing? Because if so that is a damn thick style bar. Most of the ones I've seen are built out of like exhaust tubing.
#52
I think I found the source of this style bar MossMiata.com - Parts & Accessories for Your Mazda Miata
The ones I saw on eBay are polished stainless steel and 2" OD, mine is chrome finish with 2.25" OD. Maybe that's why ebay bars are so thin, because they are a visual copy of this one but they are too cheap to add chrome plating process and knock it out of a thin walled stainless steel to save cost.
The ones I saw on eBay are polished stainless steel and 2" OD, mine is chrome finish with 2.25" OD. Maybe that's why ebay bars are so thin, because they are a visual copy of this one but they are too cheap to add chrome plating process and knock it out of a thin walled stainless steel to save cost.
#53
You notice how even Moss lists it as a style bar?
C'mon man. You're smarter than that.
I mean there's really no need to pretend. Half the cars here don't even run any bar at all, which is dangerous too, so it's not like you're doing something absurdly crazy. I just think everyone's issue with this is that you're convincing yourself that this is safe when it's not.
C'mon man. You're smarter than that.
I mean there's really no need to pretend. Half the cars here don't even run any bar at all, which is dangerous too, so it's not like you're doing something absurdly crazy. I just think everyone's issue with this is that you're convincing yourself that this is safe when it's not.
#55
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The sanctioning bodies for NASA and SCCA track days also require a minimum of one diagonal support to the main hoop and that your helmeted head not exist at a higher point than a line drawn from the top of the rollbar to the top of the windshield (infamous broomstick test).
#56
build it like this. then run your tests the material should be 1.75" .095 Dom tubing.
FYI this is a lemons cage. it doesn't get any "less" then this.
here is a typical NASA legal roll bar. note the support tube mounting position on the main hoop. also note the cross bar location inside the main hoop.
although there is some name calling in this thread. everyone does have your safety in mind, and they are trying to help you.
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Last edited by OGRacing; 01-20-2015 at 01:25 PM.
#58
the other thing to look at is that the style bar simply isn't tall enough to protect you in a roll over. that combined with the potential to be trapped by it makes running no style bar safer then running one.
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#59
mkturbo.com
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The other thing that no one has really pointed out is how the "style bar" bolts to where the seatbelt bolt in. For a roll bar that is not an acceptable mounting point. If you check out how any of the real roll bars mount, they may have a bolt there, but they also go much further down and bolt into the actual chassis.
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