Looking for some roll cage design ideas... love to see some pics. Minimal cage... 4 or 6 point.. Sent from my iPhone using The H.A.M.B. mobile app
Are you looking to race your car? if so, grab a NHRA rulebook . I can get you some pics of mine, 8 point from S&W. The rear bars go through the package tray, and it clears the headliner (by a hair).
I will be running the car at around 6 races a year. (H.A.M.B., Meltdown)... probably not any sanctioned races.... don't want a "full" cage.. and still want a back seat Sent from my iPhone using H.A.M.B.
Don't bother - it could do more harm than good if not done the "right" way.......if its just for looks have some exhaust tubing bent up.....
You would still need one to p*** tech at what ever track you run at. The event promoters have nothing to do with the track safety rules.
A functional roll cage/roll bar and a functional back seat is very difficult to combine. To have rigidity, you want the cage to be designed out of triangle shapes as much as possible, and som of the diagonal tubes that create triangles in the "main square" shape of the cage more or less has to be where the backseet/rear p***engers need space. Although you could have a bolted construction to use when racing, and throw it out again for everyday use.
My Nova has an 8 point bar and retains the stock rear seat, not easy to get the seat (or your ***) in/out but doable.
This is good advice. You should know that if you install one even in a cl*** where it's not needed it will need to meet current spec's along with safety belt mounting, wall thickness of material also. The Wizzard
DDDenny; Maybe my memory is slipping or things have changed again but that drop down door bar may keep you from making a p*** at all. I seem to remember the door bar needing to p*** somewhere near the shoulder of the driver. Am I wrong? The Wizzard
An NHRA legal roll bar would have to be welded to your original frame which makes it a tougher to install also. If it's strictly a race car then I would have one installed, if street driven I would give it a lot more thought. Roll bars are to be used with a 5-point harness and a helmet as a package.
11.50 requires minimum roll "bar" 1 3/4 x .118 wall for mild steel, door bar can be of swing-out design for driver access, Done correctly the rear bar behind the seat could be removable for daily driver/seat use. Problem with "KITs" is that they tend to make them 13/16 of what they should be for the novice to be able to get in and weld them
I used an Art Morrison kit in this '55, it fit very well. We took a little out of the bend out of the front legs, to make it easier to get in and out of the car. It has swing out side bars. One thing I did differently, is the tie bar behind the seat. I bent it to clear the tunnel and mounted it above the floor, so the seat belt mountings are exposed, and the carpet runs under it.
In another thread I said NHRA legal and was corrected then so I'm sure you are right. Actually was never intended to be drag raced, just a street car.
Does anyone know if the bar that runs behind the front seat can be "u" bent to allow the front seat to slide all the way back ?. I'm 6,5" and I can't get into most cars with roll bars.
Yes, the bar behind the seat can be curved to clear the seats. I p***ed tech with my old Morris Minor and had the bar curved to clear the seats.
I seem to remember a rule about drivers position and the main hoop. I too have curled the ends of the crossbar to clear the seats, but the driver's helmet cannot be under the main hoop. I could be wrong about this.
You can bend tubing any way you like it, but the moment a tube isn't straight anymore you have made it very much easier for that tube to bend further - in a wreck for example. If you want a rigid cage/rollbar, it should be designed with this technique, based on triangles of (mostly) straight tubes. It becomes very rigid because every change in form basically requires tubes to change length, and that doesn't happen easily. Other designs, such as squares or bent tubes can deform relatively easy by bending the tubes. But you have racing regulations to follow ofcourse. They often do not dictate the safest construction for various reasons, often it's a compromize for easy manufacturing, easy install and so on.
I got a lesson about this in fabbing an oval track car many years ago. I wanted everything triangulated but the tech guys said we needed door bars that had a curl in them. Remember, the car has to absorb energy in a crash. So while a triangulated structure is very strong, there needs to be areas that can crush in a somewhat controlled manner. As others have said, unless you duplicate everything about a race car in a street car, don't put a cage in it. If you don't wear a helmet, 5 or 6 point harness and probably a Hans Device, a roll bar or cage is more dangerous to the driver than no bars at all. Also, a race car harness will hold you straight up. In a car without a cage that is an invitation to disaster. (Ford Proving Grounds- Romeo, MI)
All of our road-race stuff has curved bars, that bump out to the inside of the door skin, away from the driver, so they can absorb impact, and dissipate it before it can reach the driver. As has been mentioned, no cages on the street. Every season I get my head bashed up by cage bars, just servicing the electronics, radios, restraints, etc., and I am only in the car when it is not moving, and for a few minutes at-a-time. I had to take out TC-B car through tech, because its driver was on the track, in another car. When I exited, I nearly knocked myself out, and that car does not even have a tight cage.
If you don't need a bar/cage by the rules, don't put one in. Once you put one in you have to meet ALL the rules for that installation. Just putting one there for looks could cause a big problem at the track. They also give you headaches on rough streets/RR crossings. SPark
Its been a long time since we have built a 6 point rollbar in a race car.( All S.F.I. cages now) but As stated before, if a roll bar is installed it has to meet all the rules. Even if the car doesnt require one, The door bar must fall between the shoulder and elbow with your arm in the relaxed position. ( with your hands in your lap) The bar behind the seat can be curved to let the seat be moved back, it can be no higher than the top of your shoulders and no lower than 4in below the top of your shoulders. Also the seat back must be mounted to the roll bar. If aftermarket seats are used and the seat backs are higher than your shoulders, the belts must p*** thru the seat. If you build a steel roll bar use .120 wall D.O.M. or .134 wall R.E.W. tubing . D.O.M. being my first choice.
Interesting... I put a 5 point bar in my 55 chevy, and drove it on the street something like 85k miles with the bar in it. I never wrecked the car, fortunately. I made a bolt in driver side bar, and only installed it when I went racing. The rear down bars were bent and the back seat was fully functional. It did take little bit of effort for adults to get in back there, but several guys did so. I put an 8 pt cage in my Chevy II, and I've put close to 20k miles on it so far. It's a little bit of a nuisance to get in and out but I've never beaned myself on it. I've never wrecked this car either fortunately. When I drive it on the street, I wear a 5 pt harness, but no helmet. There is some risk to driving this car, both on the street and at the drag strip. If you are totally risk averse, you might want to rethink the whole idea of driving a hot rod. If you are comfortable with taking a reasonable risk, then you can probably deal with driving a roll bar or caged car on the street. Some guys have rather odd ways of evaluating and living with risk.
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