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Author Topic: Would you pass this cage? Is it safe enough?
JC-MX5
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Region: NASA Florida
Car #: 33
Year : 1990
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I was on eBay just now, looking at what race cars are up for sale just for the fun of it. I'm definitely not looking to buy. Anyway, I saw a 1990 SM for sale and started looking closely at the cage. The door bars are welded to the tub instead of the main hoop (which doesn't go all the way to the floor). I thought this to be curious as I have never seen a Miata with this sort of cage. I was wondering if this would be a safe/passable way to build a cage.

Say for example, you have a bolt-in roll bar of legal tube thickness (Hard Dog Hard Core). Could you simply add the rest of the cage later, but weld the rearward ends of the door bars to the tub itself? Here's what I'm talking about.

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As you can see, the passenger side is a regular X and the drivers side has NASCAR bars. If the seller of this particular car is on here, I'm not trying to bad mouth your car or anything like that. I'm just curious to see if this would be an option for my car down the line. Thanks in advance for your input, guys!

[ 10-31-2010, 01:29 AM: Message edited by: JC-MX5 ]

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Josh Chaney
Future Rookie/Build in progress...

Ralliboy Verified Driver
Rock Star

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Car #: 33
Year : 1993
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Passable yes, Safe? hmmm...Does the car come with a log book?

If you want to go the hard dog/ weld other parts route, dont. The cage is a big safety item. Don't skimp.

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Randy Ramos

http://WWW.MeatheadRacing.com

NV Racer Verified Driver
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Car #: 70
Year : 1990
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That is the norm here in the West. There was a thread on this earlier this season and Scca issued a revision stating that this style of cage was legal since the main hoop and door bars are welded to the same plate.

Dennis

JC-MX5
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Car #: 33
Year : 1990
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The ad says the car has an up to date log book.

http://cgi.ebay.com/ebaymotors/1990-SPEC-MIAT...5fNotQ5fStreetQ5fLegalQ5f

quote:
Originally posted by Ralliboy:
Passable yes, Safe? hmmm...Does the car come with a log book?

If you want to go the hard dog/ weld other parts route, dont. The cage is a big safety item. Don't skimp.

I definitely won't be skimping on my cage, but I am trying to find a potentially cheaper, but safe route. Ideally, I want a MiataCage.com cage with NASCAR bars on both sides, but of course that's really expensive, even if I borrowed a welder and had the knowledge to do it myself. For what it's worth, Hard Dog sells a cage that is just an extension of a hardcore bar, iirc (and it's a goofy looking bolt-in).

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Josh Chaney
Future Rookie/Build in progress...

SCCA_Racer
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Year : 1991
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Take a look at the gas tank area. That secondary panel has been removed which mean the filler neck is exposed. I would want the car to be re-inspected by your local tech inspector before buying.

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Joshua Fine
SCCA member 323214 since 2003
Novice Permit in 2010
Racing 2011

JC-MX5
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Region: NASA Florida
Car #: 33
Year : 1990
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Well like I said, I'm just browsing eBay for fun. If we're being honest, I wouldn't buy this car even if I had the money. I want to build my own. It's the style of roll cage construction I'm asking about to see if it's a viable option for me. I do agree though. I'd have this car re-inspected too.

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Josh Chaney
Future Rookie/Build in progress...

Cajun Miata Man Verified Driver
Overdog Driver

Region: Houston; SWDIV
Car #: 15
Year : 99
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I wouldn't drive it. Looks like a lot of corners were cut on this budget build.

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James York


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Mitch Taylor
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Although that x does not look too beefy, most porsche cup and factory race cars use the x with gussets on both passenger side and driver.

Any cage design can be executed good and bad. and you are correct taking a car down to the raw tub and starting from scratch is usually the best but expensive. Keep looking there are plenty of good cars out there for sale keep looking. A good friend just purchased full tubed car , for under 8k.

Kent Carter Verified Driver Made Donation to Website
Future Never Has Been

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Year : 1991
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I don't think that cage could get an 'annual' in the SowDiv.

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Do I turn my 99 Hard S into a killerfast SM or seek a donor?

Greg Kimble Verified Driver
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Personally wouldnt drive with that set-up, also just curious but it that the anchor for the sub strap mounted in front of the seat?? Finally there are many good car builders in FL, the cage should be done by an expirenced welder/Fabricator even if you do the rest of the build yourself.

Greg

cam Verified Driver
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The cage is the single most important aspect of the car. IMHO, it is a poor design to my untrained engineering eye. I would not drive it in wheel to wheel racings. Should be OK for Auto-X and DEs only. My primary concerns are how the front wraps around the dash board, I can not see a platform or plate which the front connect too, passenger side X brace looks to have low quality welding, there is a missing brace along the roof, and there are missing supports that should be in the trunk. In short, it looks like a bolt in kit not designed for wheel to wheel racing.

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"The problem with Socialism is that you eventually run out of other people's money."
~Prime Minister Margaret Thatcher
"A government big enough to give you everything you want, is strong enough to take everything you have."
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Keith in WA Verified Driver Made Donation to Website
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+1 Doesn't take too long at the track before you see someone with a really bent car. Forunately, all my friends who have badly bent their cars had good cages in them. I thought I was going on my roof once, and my immediate thought was "Shit I'm going over...good thing I have a strong cage."

Racing is expensive. I fully gutted the car and got a good cage properly installed. Over 2 years, I've spent far more on tires, gas, and entry fees. Some costs, I accept once or twice a month just knowing it's the price to play the game. Other stuff, I paid the money hoping I'd never have to use it but glad to know it's there if I do.

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Keith Novak
(Will work for tires)

Dave Stevens
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quote:
I definitely won't be skimping on my cage, but I am trying to find a potentially cheaper, but safe route. Ideally, I want a MiataCage.com cage with NASCAR bars on both sides, but of course that's really expensive, even if I borrowed a welder and had the knowledge to do it myself.
The Miata Cage kit is a pretty good deal, all things considered. I started learning this kind of fab again over three years ago. I had a bunch of training in high school and some in college before I ran off to join the circus. But that was 30 years ago. At this point I have everything I need. Including the experience. That is the part you can't buy for yourself.

Let's look at what it costs to do the cage. If you have a good steel supplier you can get enough 1.5"x.095 DOM for about 300 bucks, give or take. So you've saved 800 bucks, right? No. To get to the point of that kit you will need at a minimum a chop or band saw ($200), bender and die ($700 or so after shipping) and a notcher but you'll need the notcher to install the kit. I spent 250 on my Notchmaster but you can get a cheapie for aroung a hundred. No prob, now do you know what to do with all that stuff? Of course not counting levels, degree angles and brackets for such. So now you have all the stuff. What you don't have is the design. You can look at the pics and get Bend Tech software to help ($75-250) but you still need to have at least some fab experience. So now you've got about 1500 or better into tools and material. Opps, I didn't factor in plate for the footings. Or cutting it. At 1050 to your door that Miata Cage looks pretty appealing at this point.

Now you have to put it in. Can you weld? If you are borrowing a welder chances are you can't weld. My apologies if you can. Hacking a bunch of booger welds around tubing isn't going to get you a log book. Might get you hurt or worse. At the minimum you'll want a 180 amp class mig. With gas, wire and PPE (and of course the machine) you are looking at about a grand. Around here if you give a pro welder/fabricator 500 and your car ready for the kit you can do it for around 500. Beginners will burn up 500 in coupons, wire and gas learning how to do this.

At this point the 1600-1700 buck for the kit and to have it installed looks pretty good. Compared to the 3 to 5 thousand dollars in tools and materials to design, fab and install a cage yourself.

Dave

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The 2011 Money Furnace
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JC-MX5
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Region: NASA Florida
Car #: 33
Year : 1990
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I honestly didn't think this would be taken so far out of context.

-I am more than aware of how important the cage is. I would never accept a bad job in that department.

-I'm not trying to buy an already built car, particularly this one, so please stop telling me not to buy it.

-I don't know how to weld. I want to learn, so I'm going to include it when I'm in school if I can. I would never try to build a cage myself. I don't know the first thing about it. I was speaking hypothetically when I presented the scenario of "welding a pre-built cage myself." Obviously, there's more to it.

-I can see the cage in the car is crap. The door bars look awful and don't flow together like one piece of continuous metal, as they should. I wasn't asking if I should have a cage exactly like that. I wouldn't feel safe driving a car with that cage.

-I would never ever have a cage that didn't go into/under the dash. It's half-a$$ed in my opinion.

Now, say I was having a custom cage built. I would personally make sure that the welds were done correctly and that there were no corners cut. There would be an under-dash bar, all proper roof bars and even a Petty bar if I felt it necessary. I simply want to know, could the door bars be safe in a crash if properly welded to the tub (even partially) by a professional? I'm not necessarily saying I would go this route, as I probably won't. I just want to know if this would be viable if a professional fabbed it up.

I even started to wonder, "What if the door bars were partially tied into the main hoop and the lower portion to the tub?" and I found this...

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http://cgi.ebay.com/ebaymotors/SPEC-MIATA-MAZ...5fNotQ5fStreetQ5fLegalQ5f

This car is being sold by the same people. The top door bar ties into the main hoop and the bottom door bar appears to be welded to the tub. This car also has a proper dash bar as well as a center roof bar. The fab work seems to be to a higher standard as well.

In the end, I'm more than likely going to buy the MC cage. I was always going to have it professionally welded, so no worries there. I hope I cleared up any confusion. This thread was made was merely out of curiosity.

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Josh Chaney
Future Rookie/Build in progress...

racerfink Verified Driver
Gig 'em Aggies

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Wouldn't the mounting points of the passenger side door bar add to the "8 point roll cage"? Seems to me that based on the wording of the rule book, that would be illegal for SM.

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'90 Spec Miata
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wheel Verified Driver Made Donation to Website
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The rule allows you to attach as many tubes as you want to the mounting plates. If these tubes are attached to a plate, that goes up and over the bulkhead,(where the main hoop is attached) they are legal. Of course, you can't attach the tubes to the rocker panel. I can't tell from the photo if that is the case.

JC-MX5
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Year : 1990
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I didn't notice before, but both door bars on the orange car are tied into the main hoop. This cage is definitely a better build. It looks a lot cleaner.

 -

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Josh Chaney
Future Rookie/Build in progress...

Kent Carter Verified Driver Made Donation to Website
Future Never Has Been

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quote:
Originally posted by Greg Kimble:
Personally wouldnt drive with that set-up, also just curious but it that the anchor for the sub strap mounted in front of the seat?? Finally there are many good car builders in FL, the cage should be done by an expirenced welder/Fabricator even if you do the rest of the build yourself.

Greg

Schroth requires a 'ahead of the seat' sub-strap mount on at least one of their models. Gotta follow the maker's recommendations above all....

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Do I turn my 99 Hard S into a killerfast SM or seek a donor?

Ken SM-94 Verified Driver
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The second bend on the upper door bar that allows it to get back to the main hoop isn't a good idea (orange car).

Check out the Miatacage.com cage. I wish they were around when I built my car.

Ken

JC-MX5
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Year : 1990
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As stated earlier, that's my ideal cage.

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Josh Chaney
Future Rookie/Build in progress...

-Bob-
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You'll be very surprised at the quality and number of cage builders right in your own area.

Ask them why their fabrications are better than what you are considering? Better yet, check them side-by-side your preference at your next NASA event and you will go with a Florida fabricator.

B Wilson Verified Driver Series Champ
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Just be sure to compare using the latest version and features of the Miatacage and make sure you do your research. I've heard people quote outdated information about various aspects of the Miatacage design. I'd be happy to debate the facts on this forum, but I have Miatacage's latest and it is the most advanced cage design I've seen in any car. You can't go wrong with the leading brand in this case.

Also remember that car weight balanced with safety should be a key factor in your decision. I currently have a 1.6 and make weight with 40 pounds of ballast. I weigh 182 lbs.

-bw

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Bruce Wilson
2010 Oregon Region Champ
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Keith in WA Verified Driver Made Donation to Website
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Returning to your original question of whether the door bars could be safe if welded directly to the tub and the main hoop not going all the way to the floorÖ It could be safe. It would take a good hard look at more than just that local area but more than likely it would need to be much heavier construction than a more traditional cage design for equal safety.

You can always throw lots of material at a problem but tube frames of any kind get much of their strength out of the geometry. Thatís where a well thought out design is equally as important as the weld quality.

Knowing a little about structural stuff, I have the ability to look carefully at some innovative designs and have at least an educated gut feeling of whether itís a sound idea or a bad one. If I didnít have that knowledge, Iíd look at the quality of the welds, the attention to detail, the reputation of the builder, and anything very out of the ordinary would give me reason for concern. If you donít know for sure whether itís a good idea or a bad one, itís safer to assume itís a bad one. The person inspecting your car for a log book will most likely assume itís a bad one too.

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Keith Novak
(Will work for tires)

   

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