Roll Cage what size dia. and thickness?

Hi what size pipe and the thickness should be used for a roll cage?..This cage would be used in a street car...Thanks for any info...Miller

 

You should follow the NHRA rules on the subject:

From here (The google cache because NHRA just broke their website, and the real link no longer works)

 

The current SCTA rules allow the 1 5/8, (1 1/2 in small motor classes) but its believed that they will go to 1 3/4 for the 2010 races. (Its currently "recommended")

 

if weight is not A problem 1 1/2 in black iron pipe schedule 40 is really solid if bent on a rotary bender

the nascar tube specs are not really too sturdy in the event of a horrendes crash, but they usually hold

also the diameter of the pipe is closer to 2 in and is a lot thicker walled

I dont know anything about this but built a lot of cars useing this and crashed severely and things do not move when built like this

I also bought several newer cars with the new lighter cages and WENT A LOT FASTER WITH LESS WEIGHT

always rember that speed is dangerous, how fast do you want to go????

 

Hi thanks for the fast replies....Miller

 

Bah! I was trying to find the correct link to the information on their damned site! I clicked "Post Reply" full minutes before you. Minutes!

 

it's YYrrrickey Booby

 

I will just post as fast as possible in the future, and not cite my references. Information will be less useful, but I will be first and that seems to be more important.

 

PIPE will not pass Tech anywhere. If you want it for looks only, just use exhaust tubing. If you want protection I would use 1 3/4 or 2 in. .125 wall tubing.

 

Should add that my post above was for a roll bar only. For a full cage it should be 1 5/8 tubing

 

There are some "major" changes in the SCTA Roll cage dimensions. I don't have them to hand but check at scta-bni.org I believe they are on their site. The 2009 rule book is at the printers right now and should be available very soon.

Or you could do like a friend did many years ago. I was in Ireland and the brother of a friend was into rallying. At the time a roll cage was not required but after a serious crash cages were required. He had no money (whats new?) and he worked at a plant that manufactured PVC tubing. He made a cage out of black PVC tubing and covered it in foam. He got away with it for a season and a half before he was caught.

 

Hi thanks again for the info...The car is a 31 Ford and there is not much between your door and the other guys front bumper...I am just trying to make the car a little safer for street driving and never to race it....What is the difference in pipe and tubing?..As far as weight that is not a problem.....Thanks

 

PVC tubing??............HA HA, the joke was on the tech guys (??)

 

Miller,
If you are going to do this roll cage for a car that is going to be inspected by NHRA, SCTA etc you may want to think about going with 1-3/4 dia and .134 wall thickness. NHRA is big into using a sonic checker to check wall thickness and if you go with the minimum wall thickness, .120, it will be thinner on the outside of the bends and the cage could be illegal. Going with the .134 wall prevents this. Also I would recommend going with DOM tubing, better quality and weldability.

Rex

 

WTF are you smoking dude?

NASCAR cage specs aren't too sturdy, but BLACK IRON PIPE will be fine?

To the OP:

Stock cars generally have main cages built on 1.75" OD x 0.095" Wall HREW 1010 steel tube.

I have been upside down at 100+ MPH in a car with a cage built from that stuff, and it didn't move at all. Four complete rolls, and aside from sheet metal damage, you'd have never known that the thing had been upside down.

NHRA suggests (IIRC anyway) 1.625" OD x 0.134 Wall DOM 1018/1020 steel tube.

SCTA generally wants thicker walls yet, though I do not remember the exact spec offhand.

I am building my chassis and main cage from 1.75" OD x 0.095" Wall HREW steel tube, with 1.5" OD x 0.095" Wall HREW secondary tubes, and 1" OD x 0.095" Wall HREW tertiary tubes.

If you're sure you'll never race it, you can get away with 1.5"-1.75" OD x 0.083" Wall. That will build a plenty strong cage for a car with a GVW under ~3,000 LBS, since street cars are unlikely to ever see an impact directly on the cage from another car of similar weight at race speeds.

 

Most roll cage kits (ChassisWorks, Chassis Engineering, etc.) for NHRA legal cars are 1 5/8" X .134 tubing. The minimum spec is .118 tubing, but there is enough "tolerance" in the factory tubing that they go to .134 to make sure it meets spec.
Larry T

 

check with S&W racing.they have a ton of kits available

 

i'll be the devil's advocate here: roll bars/cages in street cars are more dangerous than they are helpful.

discuss.

 

get the NHRA/IHRA rule book...build to that...will pass tech anywhere.

M.

 

Hogwash.

A properly executed roll cage does not reduce your safety on the street.

Now, that is not to say that a bar 1" from your melon is OK, but a properly designed cage will not put bars that close to your head anyway.

That means you cannot run a funnycar type cage on the street. Your head is too close to the steel to be without a helmet.

However, a well built halo cage, or whatever you drag guys call a perimeter stock car cage will not reduce your safety at all, 'cause the things are always designed to keep the tubes as far from your body as possible (which has always made the drag car specs where you the tubes can't be more than X" from your helmet seem odd to me).

As always, the efficacy of the device centers around the design and construction of said device.

 

I dont think that anyone has real evidence either way but your body and head are less restrained in a street car than in a race car. i can imagine someone in a three (or two) point belt moving to the side or up enough to hit the "halo". all bars within range of possible contact should be padded anyway

 

You know, I just always assumed that if the owner was concerned enough to put a cage in their car, they'd be concerned enough to also install five point harnesses, AND make sure that their seats and mounts were up to the task.

To me it seems stupid to expend all the effort to build a cage, and then only use two point seat belts and stock sliding seat mounts (bolted to the sheetmetal floor pan with two or three 1/4" bolts into sheetmetal nut'serts).

Also, good HD padding should be a forgone conclusion, regardless of whether the car in question runs on the street or the track. If it has a cage, all the tubes in the passenger compartment should be padded.

 

If you ask me, i think roll cages are dangerous in street driven vehicles, unless necessary by NHRA/IHRA competition. Everyone thinks they look so cool, but supposing some old lady rearends you....with no helmet you are exposing your head to .125 mild in every which way. Can you say head injury? I say no roll cages unless you plan on driving to burger king with a helmet on. JMHO

 

WOW ...You guys are great...The more I read the more I learn about my question...What is a safe distance to keep any part of your body from the cage/bars even with padding?...As I said this car will never be at a race track nor will I race it on the street... I am looking for some safe way to handle a side impact..Thanks ...Miller

 

I would say a minimum of a foot, but depending on how hard the lick is, that may not be enough.

I've hit the very top of my helmet on the steering wheel in my modified before. That is a healthy 24"-30" in a straight line, and I was wearing a five point 3" Simpson harness at the time. Granted, that was a damned hard lick, but it illustrates just how far your body will stretch, even when you're well belted in. Put it another way. In another lick of similar magnitude, just the inertia of my arms bent the steering wheel over double in two places. You could see where my hands were, 'cause there were two places where the ring was still straight. Never lost hold of the wheel, but it was a vastly different shape post impact.

I would be inclined to place the main hoop to the rear of your seat by at least 6"-8", and have the upright outboard of the seat by at least 8"-12" (basically as far out against the skin as you can get it). That puts the greatest distance possible between your melon and the steel, AND keeps the tube out of a direct line to the side or to the rear (to thwart the oft tossed about tiny rear or side impact that brains you).

The easiest way to keep your head off the bars though, is to use a damned seat with a real head rest.

I'm putting a cage in my car, because I want to be able to survive a roll over or a hard side impact. For those same reasons, I am also using five point belts, and high back racing seats.

IMO it is pointless to build a cage and use stock type belts and stock type seats (or any low back seat really). If your seat and belts can't restrain you in one place during a wreck, there is no point in even having a cage, 'cause you'll be dead from ricocheting around inside the cab long before you get smushed by the top caving in.

 

Thanks for the detailed info..I plan to use seats with built in head rests...I am concerned with a side impact more then front or rear impact...Thanks Miller

 

Good thread

 

Use 2in dia. 0.125 walled dom chrome moly tubing. Not pipe that shit is dangerous as hell if you flip over, it can buckle,pinched, and a whole lot of other things you dont want happening in that situation.

 

I'm getting the steel today to build a 6 point cage for my buggy (yeah, a glass VW powered buggy), and while it may see the strip once or twice, it will mostly be a street car with a very mild motor.

Is DOM mandatory or will mild steel be good? I'm thinking 1.5" .120 wall????

 

I actually think I know what it is you have in mind here. I wanted to add a little safety to my car because I plan on driving the hell out of it and statisitcally that increases my chances of an accident. I needed to reinforce my body anyway, so I built a "safety cage" that adds regitity to the body as well as provides more protection in the event of the "unthinkable". I used 1-1/2" x .120 wall DOM tubing and tied it into the body and sub-floor and tried to hide it the best as possible. It will not meet NHRA or SCTA standards, but will provide some protection in the event that something would happend AND the body is rock solid now. The thing I couldn't work out was reinforcing the doors. Was out of room and unless I wanted to leave the windows up all the time there was no place for reinforcing. But the 'B' pillar is SUPER strong and I have a cowl structure tied into the 'A' pillar so hopefully that will help.