The 24 Hours of Lemons Forums → Lemons Newcomers → Roll cage options..
Is there wiggle room for roll cages?
I've got this chrome molley tubing looking for someplace to be, Can I build a cage to NHRA specs and get a NHRA inspector to sign off on it at 150MPH1/4 mile or whereever their rules are?
but Chrome molley is smaller than DOM tubing..
Seems a shame to have to buy tubing when I have stuff sitting here..
Unless you get a specific waiver from Jay, then no. You can substitute moly, but it had better be the right size. You can probably get away with using 1.70 vs 1.75, but I wouldn't try to rationalize using 1" just because its moly.
The other thing with moly is that MIG welding it makes the weld area brittle. You should really TIG it or gas weld it. With that plus the cost difference, I'd hate to use that stuff on a cage.
Plus, a little give makes the car a lot less likely to be a write off when you bonk one corner.
I know old-school racer guys who built a chromoly cage and never did it again after a shunt that rendered the car unstraightenable... Not that we care much in Lemons about a car that has a permanently paralellogrammed chassis, but go with DOM mild steel if you can.
Unless you get a specific waiver from Jay, then no. You can substitute moly, but it had better be the right size. You can probably get away with using 1.70 vs 1.75, but I wouldn't try to rationalize using 1" just because its moly.
The other thing with moly is that MIG welding it makes the weld area brittle. You should really TIG it or gas weld it. With that plus the cost difference, I'd hate to use that stuff on a cage.
I'm pretty sure it wouldn't pass a NHRA inspection unless it was TIG welded. That plus the Cage tubing has to have large enough size to it to survive a accident at 150MPH.. Those inspectors are sharp. I believe it's not only slightly smaller in diameter but also thinner wall. I suppose I really should drag it out of the dark and measure it to makle sure I know exactly what I'm talking about..
As for keeping things straight during the welding process, I have a surface plate for that.. ;-) actually I have an old printers layout table that's 4 inch thick surfaced steel.. That thing isn't an ant's fart off of dead level and it cost me an hours worth of work to haul it away..
I've seen the banana that some people turn their car into welding a cage into it.. IT doesn't matter if it's DOM or ERW or Chrome molley..
The rule is only 4 down legs allowed isn't it? Otherwise the cost (Value?)of the cage goes towards the value of the car? IF the down legs are welded in various locations on the body that is still only 4 down legs isn't it? or does each brace count as a down leg?
I'm thinking of tying the cage into the door bars etc..
Dragster style cages would be allowed correct? Full width roll cages aren't a requirement are they?
Plus, a little give makes the car a lot less likely to be a write off when you bonk one corner.
I know old-school racer guys who built a chromoly cage and never did it again after a shunt that rendered the car unstraightenable... Not that we care much in Lemons about a car that has a permanently paralellogrammed chassis, but go with DOM mild steel if you can.
MY thinking on cages is that unless it's allowed which I believe the rules don't with only 4 down legs allowed. The cage should be a cocoon. Allow the car to crumple around the cocoon, absorb energy and let the cage protect the driver. XJ-S bodies are cheap to free while a human body is darn expensive to rebuild.. ;/
Is there wiggle room for roll cages?
This question has the same answer. Do insurance underwriters have a sense of humor?
It is worth trying to save $350 in tubing to be rejected at tech?
Although not specifically stated in the rules (at least where I can find it), they do want a full size cage. You can have as many legs down as you want - 6 is the minimum fronts, main hoop, and rear stays. Fron there, you can add fronts to the fire wall, doorbars to the sill, diagnal to the floor, rear stays to the floor, etc. have at it.
I build cages - simple, well built, good design, and good welds will be better than a complex birdcage where your welder can't reach everywhere they have to and will leave ugly and incomplete welds.
It is worth trying to save $350 in tubing to be rejected at tech?
Although not specifically stated in the rules (at least where I can find it), they do want a full size cage. You can have as many legs down as you want - 6 is the minimum fronts, main hoop, and rear stays. Fron there, you can add fronts to the fire wall, doorbars to the sill, diagnal to the floor, rear stays to the floor, etc. have at it.
I build cages - simple, well built, good design, and good welds will be better than a complex birdcage where your welder can't reach everywhere they have to and will leave ugly and incomplete welds.
Totally agree with what Rob says here.
Spend the money on the cage. Find somewhere else to pinch pennies. The extra 50-100 bucks you may spend to make sure a car is safe could mean much more in the long term.
Read the rules, man! It doesn't say anything about "four legs down". Don't assume that any other ruleset that you've ever read before has anything to do with the Lemons rules. Read the rules!
The rules will quickly tell you that the specs are a MINIMUM, and that 6 mounting points are required (front and rear hoop and two backstays). They will also tell you that front and rear hoops must be full-width, which answers the question of a full-size cage.
Get creative with your theme and your drivetrain and suspension engineering if you want to, but simply read and follow the rules for safety equipment.
http://www.24hoursoflemons.com/pricesandrules.aspx
3.1 Rollbar and Structure
Hasn't the "I know more about cage building than the rulemakers" questions been asked a million times? Use the search to look for "cage rules" to see 28 pages of threads containing the same basic replies as the ones above.
MY thinking on cages is...
...completely irrelevant. Build, or have built, a cage that meets or exceeds the letter of the rules. Print them out and hand them to the builder--or if you are the builder staple them to your forehead, tape them to the dash or otherwise commit them to memory.
The cage should be a cocoon.
No. You should not get out of the car after your stint metamorphosed in any way. The point of a roll cage is to prevents it's occupant from being smashed in a rollover, impact, or other incident. Most importantly, it must meet the requirements outlined by Jay's crack legal team Loren linked to above.
I was really hoping to have wings after my first stint.:(
This thread is also a good source of information for cage building. Helps fill in some areas and it has pictures of what it should look like.
http://forums.24hoursoflemons.com/viewtopic.php?id=3334
All of the above have stated the situation well. Tubing must be of at least the minimum diameter and thickness and the cage must be full width and have at least 6 points of contact with proper spreader plates. Done.
Contact me directly if you have any questions.
-John
It is worth trying to save $350 in tubing to be rejected at tech?
Although not specifically stated in the rules (at least where I can find it), they do want a full size cage. You can have as many legs down as you want - 6 is the minimum fronts, main hoop, and rear stays. Fron there, you can add fronts to the fire wall, doorbars to the sill, diagnal to the floor, rear stays to the floor, etc. have at it.
I build cages - simple, well built, good design, and good welds will be better than a complex birdcage where your welder can't reach everywhere they have to and will leave ugly and incomplete welds.
One of the difficulties of the internet is that you can't see me or my shop,
Since that is the case I won't be offended that you are treating me like so many of your novice racers. However careful reading of the post should have given you a clue..
You should however be willing to accept the opinion of professionals Like NHRA inspectors who certify a cage as being safe to crash at speeds around 150MPH (and put their signature on the inspection tag)
If you were sitting here in my shop a quick glance around would change the whole tone of your answer.. Over there is a XK-E V12 roadtser I built that has a chrome Molley cage that is beautiful.. the welds look like a sewing machine did them they are that perfect for penetration and properly done.. (Nope no changed direction and nice and even..)
The cage in the "D" type is equally well done.. In fact all of the work is really tidy, neat, and clearly show a knowledge of the demands of racing..
Start checking out those cars and you'll see a lot of really beautiful creative touches that many people over the decades have admired and complimented me on..
Bottom line, I have been building and racing cars since the early 1970's, I've never had a complaint about my workmanship or work..
I have recieved compliment after compliment from tech inspector and fellow competitior.
I read the rules but if you understood the differances between Chrome Molley and DOM or ERW you'd understand the real nature of my question..
Yes, I did write that. 
Hasn't the "I know more about cage building than the rulemakers" questions been asked a million times? Use the search to look for "cage rules" to see 28 pages of threads containing the same basic replies as the ones above.
OMGuar wrote:MY thinking on cages is...
...completely irrelevant. Build, or have built, a cage that meets or exceeds the letter of the rules. Print them out and hand them to the builder--or if you are the builder staple them to your forehead, tape them to the dash or otherwise commit them to memory.
OMGuar wrote:The cage should be a cocoon.
No. You should not get out of the car after your stint metamorphosed in any way. The point of a roll cage is to prevents it's occupant from being smashed in a rollover, impact, or other incident. Most importantly, it must meet the requirements outlined by Jay's crack legal team Loren linked to above.
Justin,
First if you knew me you'd know that no cage I build will ever be substandard. So yes it will exceed the requirements.
Nothing I am asking about is shoddy or cheap! (price chrome moley if you doubt me)
Yes the goal of a cage is to protect or cocoon a driver..
Too many people use the rollcage to stiffen the chassis and with it improve the handling.
Back in the 60's ,70's and right up untill pretty recently rollcages were simply an extension of the chassis..
Now we know that it is better to let the chassis absorb the crumple/crushing and protect the driver with the cage..
I am saying that the sole goal of a cage is so that in an accident the driver walks away unhurt. Now My question for you is do you
understand why it would be safer in a Chrome Moley cage than a DOM cage? Hint, look up the strength of each type of tubing.
Geez, this is so simple. Follow the rules or start your own series. WTF
I have no doubt that Jersey Mike's Mustang Fab can MIG and TIG a quality joint that will pass NHRA tech every time but drag race cages will not pass any road race tech. SCCA/NASA/BMWCCA/PCA/Lemons/Grand-Am road race cages will not pass SCORE tech. SCORE cages will not pass MIL-STD-1290A light fixed and rotary aircraft crash resistance.
I think the problem is that people don't realize that it's not Jay/Nick/Lemons staff that really set forth the requirements. It's the insurance underwriters, so the rules are there to keep them happy. Deviation from them risks voiding the coverage. Your cage might very well be stronger than what's required. However, if you're involved in an "incident" and the insurance investigators find out that your cage wasn't built as required by the rules, who do you think's going to get hammered? That's right, Jay/Nick/Lemons staff. That's why there are pretty much NO exceptions/waivers to the cage requirements any longer.
OMGuar,
No one is saying that you can't use Chromoly tubing, only that it still needs to be at least the same size as mild steel.
Lemons spelled out what they are looking for in a cage on thier rules page. That is what has been worked out with the lawyers. If it doesn't pass muster at tech, you won't be allowed to run without fixing it. NHRA is different than Lemons and thier cage specs are different because that is what they worked out with thier lawyers. SCCA and NASA each have thier cage specs and lawyers too.
You asked if there was wiggle room for cages in Lemons. Let's turn that around a little - If I asked you if there was wiggle room on a 150MPH NHRA cage, how would you answer me?
we had a guy similar to you build our cage. I told him what tube met spec, gave him the rules, pointed out some things, and after talking to him, he said I'd be getting NASCAR-type door bars, extra attachment points to integrate the cage with the unibody, etc.
well, he moved to the beat of his own drum, and what i got was a VERY basic cage, 6-points, X-bars for the doors, no extra attachment points, and backstays with curves in the bases(which, if he had looked at the cage rules I provided, specifically disallowed this) I went back to him, and instead of fixing the cage/putting in the one he promised us, he spent DAYS arguing with Jay/his staff and i was finally OK'd to run as-is. that is, until the summit point tech inspectors put a firm smackdown on the whole affair and i had to fix it myself, mainly because i won't go back to a guy who ignored the safety specs i provided him to build the cage to, AND wouldn't deliver on promises made. He felt his 30years of cagebuilding to be superior to whatever spec the Lemons crew determined, but in the end i would feel the sting.
we have no qualms with your reputation or skill. same with the guy I used. the issue is not building a cage that meets the basic requirements for the series. feel free to email jay/john and tout the virtures of the superior strength of moly over DOM, but what they say ultimately goes.
OMGuar, we really are just trying to help you. Rob and I (and possibly others that have replied) have worked the tech line for Lemons. We've also done tech for the SCCA and other organizations on track days and race days. We want you to have a fun and safe weekend. We want you to pass tech with no fixes the first time through. We do not want to send you back to your paddock spot to flail and bang out a new cage over night then get on the track the next day exhausted and wreck. We do not want to have to build, or finish building a cage for you the day of the race because your cage was not built to spec the first time around.
I read the rules but if you understood the differances between Chrome Molley and DOM or ERW you'd understand the real nature of my question..
Our comprehension of chro-molly vs mild steel and DOM vs ERW was never in question, your question was,
I've got this chrome molley tubing looking for someplace to be, Can I build a cage to NHRA specs and get a NHRA inspector to sign off on it at 150MPH1/4 mile or whereever their rules are?
The answer, which has been repeatedly said as "no" or "probably not" were completely on point and apropos.
One of the difficulties of the internet is that you can't see me or my shop,
Since that is the case I won't be offended that you are treating me like so many of your novice racers. However careful reading of the post should have given you a clue..
No disrespect intended, but your question wreaks of noobness. Which, is perfectly fine, everyone is new to something at some point...you are new to Lemons.
You should however be willing to accept the opinion of professionals Like NHRA inspectors who certify a cage as being safe to crash at speeds around 150MPH (and put their signature on the inspection tag)
What "we" should do is completely irrelivant...I mean really, we race in $500 crap cans and spend more time with our team mates thinking up new, ridiculous themes, figuring out how to make obscure cars reliable/fun/safe and wrenching on cars than with our families, so when we think something is okay, that's when you should really worry.
The fact remains that Jay has lawyers and insurers that require X, Y & Z to be done. X, Y &Z are outlined in the rules. We all built our cars to meet these requirements. You too, can follow them or send Jay & Co. an email extolling your superior design knowledge and reputation. They might give you a waiver. They might also laugh at you and tell you to build to meet the rules.
I have been building and racing cars since the early 1970's
Congrats. Make sure you tell the Judges and Jay that when you see them at tech, BS and the penalty box.
I'm thinking of tying the cage into the door bars etc..
Good idea.
Dragster style cages would be allowed correct?
No
Full width roll cages aren't a requirement are they?
Yes they are.
How about this? Sell your chrome moly tubing to an NHRA guy looking to build a cage that will withstand a 150mph impact and be inspected by the NHRA. Take that money and buy the correct diameter and wall thickness DOM tubing that will be inspected by the Lemons tech guys. Use the rest of the money to buy beer. Everybody is happy.
There are different types of cages for different applications, because things go horribly wrong in different ways. The types of impacts you might have in road racing are not the same you are likely to have in a drag race.
Look at cages from different types of pro racing - they aren't all the same, because of the type of protection they need to provide. There is a reason that they need to be constructed differently.
Personally, without making any assumptions about your ability to construct a safe cage out of chromoly, I'd still recommend against it. Mild steel has more of a tendency to bend before breaking. I'd much rather have a cage that deforms a little bit than one that breaks and sends a piece of tubing through me. And I'm pretty sure that even with TIG welded chromoly, NHRA rules still require heat treating the assembly after welding. Seems like a lot of work, and one more thing that could go wrong. Again, I'm not saying you aren't capable of doing it, just that I wouldn't.
It's been touched on before, but cages that are too strong do nothing but transmit all the impact force to the driver. I was reading something the other day, and I can't recall which series it is - maybe for rally cars, but they were talking about rule changes to specify weaker softer material for tubing that extends outside the main portion of the cage - to create a crumple zone in the cage itself, since the cages there have been mainly designed to stiffen the car. In fact, they have been so successful at that, they have made the cars much more dangerous for the driver.
I also approve of selling the expensive tubing and using the extra money for beer. This is probably the best advice in the entire thread.
Justin,
First if you knew me you'd know that no cage I build will ever be substandard. So yes it will exceed the requirements.
Nothing I am asking about is shoddy or cheap! (price chrome moley if you doubt me)
You have to realize that everyone is trying to help. No one is personally saying you do bad work.
My team doesn't have the skills and wouldn't trust our selves to build our cage so we went to a local cage builder. He had built cages for a variety of things but not Lemons, cause this year was the first time there was on in the state. He built the cage and it looked good, quality welds and all. Unfortunately it didn't fit a couple requirements. Another team getting their cage built there saw our cage and emailed me which had me email nick and a very long stressful day occurred, with at one point it getting suggested we rip out the cage and find someone else to build it. With not knowing another cage builder and only a couple weeks left to the race it wasn't something I really wanted to deal with. Luckily I was able to get the cage builder to work through the issues with John and it was fixed and we passed through tech with no problems. (ok the tech inspector did complain that he got some wet paint on his hand but seriously we painted that the previous Sunday who would think the paint would still be wet 5 days later).
Everyone basically want you to get your car through tech quickly effortlessly, then have you get massacred by the bs judges (nothing personal just more fun to watch then getting through bs easily), and then racing on the track.
I think the problem is that people don't realize that it's not Jay/Nick/Lemons staff that really set forth the requirements. It's the insurance underwriters, so the rules are there to keep them happy. Deviation from them risks voiding the coverage. Your cage might very well be stronger than what's required. However, if you're involved in an "incident" and the insurance investigators find out that your cage wasn't built as required by the rules, who do you think's going to get hammered? That's right, Jay/Nick/Lemons staff. That's why there are pretty much NO exceptions/waivers to the cage requirements any longer.
Then according to that sort of thinking all cages are built exactly the same.. without regard to the car they are built into?
Of course not! There is a whole lattitude of the way cages are built.. Simply walk through the pits and take some photos or measurements..
It's not my goal to break new ground.. To reinvent the rollcage. I've been racing for far too many decades to imagine anything I come up with
is new or better.. However methods that have been approved and proven safe in the past may be worthy of new interest.
The prime Issue I asked about is Chrome Moly there is no listing of it in the rule book..
I can clearly understand why.. it's extremely expensive compared to DOM. However under certain conditions the opposite is true.. As in the case I listed.. That plus the tube bender I have access to has only the mandrels for Chrome moly tubing. They don't fit DOM tubing.. Or ERW.
IF you spent a few moments with a engineering book you'll see how much stronger chrome moly is. that strength translates to added safety.
Now here's legitimate reasons not to allow Chrome moly.
It can be used to make the chassis stiffer. The stiffer the chassis the easier it is to get the car to handle properly..
a Cage made from Chrome moly might be as much as 40-50 pounds lighter. ( a complete chassis made from Chrome moly would be as much as 100 pounds lighter but since no tube frame cars are allowed .............
Finally if the reduced wieght of a Chrome moly cage was required to be competitive the added cost would simply drive racing costs up.
Since there are so many legal ways to remove weight a few pounds lighter wouldn't matter, if it did simple have a the chrome moly cage car carry ballast equal to the weight savings.. `
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