I was just wondering if anybody has tried to make a roll cage that is more ergonomic than the standard 8 or 10 point cages available for our cars. When I say ergonomic, I'm referring to the continued use of the rear seats by passengers, the use of the entire trunk for cargo, and the cage is more form fit to the car than normal.

I know this wouldn't be as safe as the typical 8 or 10 point, but would something like this be viable if you wanted to make the chassis stiffer without losing too much functionality while increasing occupant safety in a roll over? I was thinking either 1"x.120" 4130 or 1"x.156" 4130 tubing for something like this.

 

If you build it with smaller diameter tubing, it will be for show only and not provide any driver protection which is the main purpose of a roll bar/cage. 1" tubing will offer no protection.

A full cage can be built using 1-5/8" tubing for many of the main tubes. 1-1/2 and 1-1/4 tubing is used for the secondary tubes.

A roll bar (no halo or a-pillar tubes), can't be made from anything smaller than 1-3/4" tubing.

If you "need" a full cage then you need it because of track rules. It then needs to be built to pass a track tech inspection. Having a full cage in a slow street car will help but your insurance company will probably refuse any coverage if they find it has a full cage. If you have a full cage in a street car then passenger comfort is at the low end of the scale.

 

I've never heard that before... is that the case for a roll bar also, or just for a cage? So what do all the street cars with a cage do for insurance?

 

ive never had an insurance company inspect my car before... ive had a bunch of cops do it tho

dont put the cage in if it doesnt need it. i just put a 8pt in mine with swing out door bars (helped a WHOLE lot) back seats are usless... not to mention it wouldnt be safe and any accident would likely kill the person in the back. u can build watev u want for looks/"ergonomic" but theres a reason the NHRA specifies tech inspection and strict design/installation rules to be followed. either do it right to NHRA specs and kno uve created a stiffer/safer car or do what u want and know u prob didnt do anything but add weight.

 

Forget about having passengers in the back seat. Not possible unless you have a main hoop only.

But as far as ergo goes, you want to push the main hoop and halo bars 'out' as far as possible. This provides more head room (so you don't crack your skull on the tubes) and more crush zone (in the event of an acident, the cage has to be crushed farther in order come in contact with the occupants.

I have my a-pillar/roof/halo bars within an 1/8" to the outter roof skin in the area closest to the driver / passenger. The top corners of the main hoop are within 1/2". I had to remove most the steel structure in the roof to get it this close. For the main hoop some sheet metal removal was necessary, along with some hammering.

You have to be precise with your bends and fit-ups. There is no such thing as a pre-bent kit that will give you this. Measure 18x, bend, fit, bend, fit, bend a little more, that’s just right. It is very time consuming process to get to this level of precision. I wasn't happy with my first main hoop, so I had to make another. Somehow I got both A-pillars right the first time.

http://www.f-bodysport.com/cage.htm

 

I took a look at the pics of your cage Big Mods, that's a really first rate cage!!!! Very nice work!

 

Yea really iv never heard that before eiether. iv seen many cars with 8, 10 even 12pts or more driving on the streets. . . i dont think the guy with the 50k+ car would driving with out insurence on the streets.

 

i have heard that some collectors insurances do not like caged cars.

 

Then don't tell them that you have one.

 

most collector car insurance companies do what they call agreed value, which means they come and look at the car, and then both of you sit down and decide what the car is worth. they will actully look at the car, not just take your word for it.