What are the rules about roll bars? I know there are SFI specs about cages for the faster cars, but there doesn't seem to be much about the roll bars aside from General Regulations 4:10, and it doesn't mention how tubing is bent, although it does talk about mounting requirements and welding processes. Most guys think a roll bar has to be 6 point, but the rules never mention a pass side door bar...I think hardly anyone actually reads the rule book carefully, before talking about what's required.
The only problem I found with bends is that depending upon method of bending the tubing is stretched. That can thin the outside metal of the bend to below wall thickness required. Do they and how would they check that is the magic question and you would know far better than most of us what work s and doesn’t. That’s why I bought my cage in kit form. Now I just worry about my weld neatness. No grinding and dressing the welds if I’m reading it correctly.
I have read the NHRA rule book carefully and am therefore self-qualifying myself to talk about what's required to successfully pass a true NHRA certification The reason I was asking is I am actually very aware of what's required to meet true NHRA roll bar and roll cage certification to the point that the cages and bars I built (out of mild steel and bent on my own bender) were built out of .134 wall tube due to possible manufacturing inconsistencies in .120 wall failing to meet the NHRA .118 requirement when/if subjected to sonic testing. I have personally witnessed cars fail NHRA sonic testing after using .120 wall. As for bends, if 1 5/8" tube (required for true cages in typical "door cars") is used (for example), in order to pass NHRA certification, the tubing needs to maintain its 1 5/8" diameter, before, during and after any bend. That is not something I dreamed up. That required consistent tube diameter is lost when tube is bent on an exhaust tubing bender. The typical consensus has always been (in my neck of the woods at least) ... if you build your car to NHRA specs, your car will be accepted anywhere. I do realize that passing "tech" at a random local track is not the same thing as passing a legit NHRA certification and I don't believe you ever claimed this could or did pass an NHRA certification but, with my knowing what IS required to pass a true NHRA certification, I was surprised to see what looks like a muffler bend on your main hoop. I have an NHRA rule book in front of me but, I am only up at this hour due to a spider triggering one of my security camera's, I am up when I shouldn't be so I am heading back to bed. I noticed that you didn't actually answer my question and that's fine ... I'm over it, carry on
From my Experience, National events race tech is By the Book to compete @ a event or race then a track that is NHRA Sanction, Pro Certifications are different then Passing tec , My piping was built to Pro certification But I never Registered ,I do Not compete at a National Race / Event. When Eric was killed in early 2000's I had my chassis Up dated to New rule @ time just for peace of mind , in cage Area. NHRA has Made / Enforced certain Rules /Specs in Last 20 years then Went back to Old Rules , One of was the use of ""Condition -N 4130 "" To ""Heat -Treated " a failure do to cracking , Back to "Condition -N ". The NHRA rule book that most of Use /Have seems to be Not Complete ! I believe main Tech is Baker ? If I recall , I have tried to reach a few times for Clarifications on Rule's because Hearing & seeing Racer's Disqualified @ National events & did Not see in Regular rule book . So National events more Restrictive then Local NHRA sanction tracks, I prefer the Black Sheep Track .
That's the thing, isn't it? You automatically look for what it takes to pass a certification, when all the car needs to do is pass NHRA tech inspection at a track, for a speed that does not require certification. If you could point me to any NHRA/SFI documentation that specifies tubing diameter and thickness, after bending, for a 10.00 roll bar, I'd much appreciate it. But I think there is no such documentation, because a 10.0 roll does not require anything more than being made from 0.118 wall tubing, min OD 1.75" to pass NHRA tech inspection. I can't find any documentation for this for 8.50 and slower cars that need to get certified. The SFI stuff is only for 8.49 and quicker cars. Oh, thanks for the explanation of what it takes to build a cage for a fast car. It's neat stuff, and it's good to hear you're taking it with the seriousness that it deserves.
If there are truly no specifics regarding NHRA 10.00 roll bar bends, then a person could, hypothetically speaking, buy the correct/legal diameter and wall-thickness tubing then hammer it flat, bend it to their required angle, install it and be arguably and technically legal. I took a meander through my old rule book and ... I can't find anything . I took a look through the online 2025 rule book and ... once again, nothing . Some internet searching does show different race bodies (not necessarily drag but road race) that do state bend specifics but, as it stands right now, you appear to be correct as far as NHRA specifics. That being said, I have an email into NHRA tech asking if a "crush" muffler bend is legal and if it isn't, where is that stated. I am shocked and stunned that NHRA doesn't appear to state anything regarding quality of bends ... as long as the tubing started out legal, anything goes just doesn't make sense. From a Canadian Rally Car site ... "30. 1.5 . 1 One continuous length of tubing must be used for each of the hoops with smooth continuous bends and no evidence of crimping of wall failure". My apologies if I am wrong (as it appears I am), I now feel stupid paying a good chunk of money for a JD Squared bender and several dies when "$5 a bend at the local muffler shop" would have sufficed I'll report back when I hear from NHRA. Admittedly, I haven't had a lot of luck getting responses from large corporations but I want it in writing and will hound them until I receive a response As a side note, something is tickling my balls Oh look, it's just my tail between my legs If the NHRA finds a muffler bend not sufficient, they sure don't make it easy to locate that info IF it exists at all. Of all the things I've ever lost, I miss my mind the most (a bumper sticker I used to have ... seems applicable today though ). Once again, I apologize ...
So, with that being a unibody car, do you have plans to put diagonals in, pretty sure that is an "across the board" requirement for unibody cars, at least in regards to NHRA rules.
Thanks for the apology, but I think the issue runs pretty deep. I'm an engineer, and I'm pretty well used to reading drawings and specs and having to figure out what is required, vs what is a good practice, or whatever. Most of the folks doing fabrication and tech inspections on drag cars don't see the world quite the same way that us engineers see it. If you're doing work for people, you have a choice to do the minimum required, or do the best you can, or somewhere in between. You can make a legal roll bar or cage that looks like crap, but that isn't going to do your business any good. I haven't purchased the SFI documents to see if maximum bend deformation is specified in them, but it sure is not in the non-SFI NHRA regulations about cages and bars in 8.50 and slower cars. They say what material you have to use, but they don't specify that it has to maintain that diameter or wall thickness after being bent, nor what type of bending equipment is required. I think the are assumptions about this being made by a lot of people, and if these assumptions cause cars to fail tech inspections when there is no rule that says they should fail, then there is a serious problem with the tech inspection process.
You really ought to read the rule book, and see if your assumption is correct. Keep in mind that this is a car that will run 10.00 or slower, and has it's original floor and firewall.
@borntoloze. Sometimes you need to be careful how much you poke the giant. Those rules might be in a gray area now. You ask a question and they look at them it might mean a bunch of changes for a lot of people. I am not against safety requirements. But I would not drive fast cars if that was all I thought about!
I'll add that all track are teched different even going by the rule book, it's based on who's interpretation of what. We have local guys that run at national events on a regular basis, they try to test n tune at the local track and the local tech nazi tells them everything that's wrong with their car and why it can't pass tech. Lol
Just yesterday I described Smokey to someone. He's one of my heroes, I'm glad I got to meet him before he passed.
I don't do drag racing, but have been (in the past) pretty involved with circle track racing. There, each track had its own rule book. How and by whom the existing rule book was interpreted was almost as important as how the track enforced its rule book. In circle track racing, the rule books were often interpreted as either telling you what you could do to/with your car, or it was interpreted as telling you what you couldn't do to/with your car. Those two interpretations could be a pretty long ways apart. From there it mattered if the track considered the rule book as suggestions (not enforced very much), or requirements (followed with reinforcement). At some tracks, the level of enforcement could have been determined by how popular the car owner/driver was, or what fit the tracks desires of the day. The standing opinion of any track's rules, pretty much come down to you had to know how the track you raced at viewed and enforced their rule book.
too late, I already built mine. But it's neat to see how many varieties they have, none of which are exactly what I needed.
And I am just here for wheelie videos... Thanks again Jim for posting your build and travel threads. They are the best!
I think Jim should take a week and come watch the corn grow. I have a feeling my project would be done if I had his knowledge and abilities for a week. Of course my chiropractor would feel left out as I get a couple days of work and then I have to visit him. Maybe he could road trip the Cheep just to work the bugs out.
Jim, I believe the Lakewood style bolt in bars are still legal. One back brace and an added driver side . No, you don't need a passenger side bar. All that extra stuff has been added over the years for rigidity.
You can bolt the roll bar assembly into the car, if it has 6" square plates on the bottom, and you can put a matching square plate under the floor. Which is not so easy to do on many cars, but probably is possible on this one. I just welded them in. You can't really install/remove it because the downbars all get in the way of moving it, once it's all welded together. And the bars have to be welded together, as far as I can tell.
Hey @squirrel Hey Jim, I really have to hand it to you for going deep into the rules, to illustrate to all concerned about the rules of the roll bar installation. It brings to mind, the famous sentencing scene from the old classic movie " Inherit the Wind" The tone of the Judges voice " Henry Morgan " says it all!
thanks, but it's not a deep dive, it's just reading the rule and understanding what it says, and more importantly, what it does not say.
General info , for those interested. Somewhere in that guide, it mentions padding, where ever the driver could come in contact with the bar, i.e. on the side bar and on the driver side of the main hoop . Also a head rest, but usually a high back bucket seat will suffice. Once you have a bar, you'll need a 5 point racing belt, whether or not the ET requires a bar in the first place.
Padding is only where the helmet can contact the bar, so the side bar doesn't need it. I built head rests into the roll bar/cage on the older cars I had with low back seats. This one has high back seats. And it also mentions that you have to bolt the seat back to the lower cross bar, which I did.
@squirrel or any one have a link for Pdf file on line for Full / Complete 2025 NHRA R-B I looked on line did not find , Over weekend another controversy , From my understanding Rule is No Modifications Allowed to part !! But Manufacture made / designed /produced , & part was used they way Manufacture intended to be used. So No modifications were done.
I searched for 2025 NHRA rules, and this is the first result https://www.nhraracer.com/Files/Tech/2025 NHRA Rulebook.pdf I think you're right about not modifying SFI approved parts...you could read the rules and see what it says.
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