roll cage for no particular reason: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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July 7, 2008 9:06 p.m. oldopelguy HalfDork

So, I have a couple old Opels I'd like to feel more comfortable in at todays highway speeds with the 3-ton tanks that seem to be everywhere these days. One in particular needs some rust repair and could benefit from some stiffening while I'm at it. Neither of these cars is going to ever track race with SCCA, the one might see a drag strip a couple times and both probably some non-competative autocrossing, maybe a Silver State run someday if I win the lotto. These are going to be weekend drivers, maybe daily drivers if they're running well, your basic sleeper hot-rod that'll shut down a rice-rocket at a stoplight once in a blue moon.

I'd like to add a 6 or 8 point cage while I re-do the cars. I'm a pretty good welder, and have all sorts of welding and cutting equipment in the shop. I don't have a tubing bender and it's third in line behind a new mill/lathe and a Ironworker, so it's not in the cards right now.

Just how bad off would I be with a pre-bent drag cage kit from Jegs or Speedway, as compared to a DOM one custom made? I know it doesn't meet current road race specs, but it was pretty much the standard cage for half a century, so it's got to be worth something in improving the crash-wortiness of a car, right? I know all the concerns about hard metal objects in a street car, and I'm ready to deal with that, but being able to mount a shoulder belt to something solid and support the front of the car for a one-piece front-end are more critical.

Alternately, anyone got a bender I could use for an afternoon in the Atlanta area?
July 7, 2008 9:21 p.m. Izzy's Cages New Reader

I'd suggest sticking to a 6+ point rollbar. Keeps all of the stuff away from your head, gives you some side impact protection etc.

One big plus of a custom bar would be that they could make it much tighter to the body, smaller diameter & thinner walled tubing etc. The prebent kits never really fit all that well and they're always heavy. Make some patterns and take it to a local cage guy to bend up your hoop and other bent tubes.

Also just an FYI. Welding is only about 10% of an actual cage install. The prep & fab work is where all of the actual work is.
July 7, 2008 10:35 p.m. carguy123 Reader

A big downside to roll bars is that you are more likely to have head to metal contact with even a moderate shunt. You almost need to wear a helmet while you drive.

Now with that said, you should be able to design a bar that is sufficiently far from the body that contact is unlikely.
July 8, 2008 12:43 a.m. NYG95GA Dork

I would say it depends on the bar and the car. I put a Kirk 4 point into my Neon just because I've always wanted a car with a roll bar. The design is such that I could never hit my head on it (unless the crash was so violent that the bar wouldn't be a factor). I put it in for no other reason than that I've always wanted one OTOH, an Opel GT is much smaller than a Neon, and it might not have the space to pull it off; I'd say to look around at some installed bars (if you can find any).

I say if you feel strongly about it, you should do it.
July 8, 2008 5:32 a.m. ddavidv SuperDork

I have a cage in my race car that is still street legal. I do not recommend you do it unless you need it to race. It's a colossal amount of work to install. It sucks useable interior space. And it is truly a safety concern when not wearing a helmet. If you do elect to go down this path (I would not), only SFI padding should be used...and lots of it.
July 8, 2008 6:08 a.m. oldopelguy HalfDork

Neither car is an Opel GT, one's a Kadett wagon and the other an Ascona sedan, so both have a lot of headroom and I'm well prepared to pad as necessary. Most of the interior of both cars is bare steel anyway, the Kadett is pre-'67 and doesn't even have a padded dash, so addind some padded steel tubing adds less danger than in most cars. The Kadett starts out at 1700#, so adding some weight with the cage isn't a huge concern.

My real concerns are to have something sturdy to mount a real harness to, adding some stiffness to the chassis (to make up for what it's losing when the floor gets cut for it's engine swap and front end get's made into a 1-piece) and adding some side impact protection. All those things you guys always recommend a cage for.

The real question is whether or not one made out of non-DOM tubing is inferior enough to a DOM one that I need to step up and do it "right" regardless of the costs.
July 8, 2008 6:31 a.m. 44Dwarf New Reader

Doug Gore from Speedway Illustrated has done several test and articles on cage metel and layouts too. His finds are non DOM cages are just as good and in some cases better!
Tubbing is made in todays world light years ahead of the tubbing from the 50's and 60's infact the man who said don't use a seemed tubing Mr. Carrol Smith was qouted serveral times before he passed a away that "i wish i had not made that statement, todays seemed tubing is safe"

To bad your not in Mass i'd let you use the bender for a small fee. but i only have 1" and a 1.5" die set.

44
July 8, 2008 8:48 a.m. aussiesmg HalfDork

Just put a prefabbed cage into my GRM challenger, it took some tweaking but was a lot less work than a custom cage, I scored a deal on it though, but your less likely to have that happen for an Opel.
July 8, 2008 12:13 p.m. GlennS HalfDork

Would a 5 point harness cut down his chances of hitting his head on the cage?
July 8, 2008 12:55 p.m. phillyj New Reader

wouldn't a roll bar be more safer than a cage as it only occupies the rear portion of the car?
July 8, 2008 6:12 p.m. Izzy's Cages New Reader

IMO, a properly placed multi-point roll bar is "safer" than a full cage in a daily as long as the harness' are utilized, a proper fixed back seat and SFI padding are used.

I say "safer" because once you add a bunch of tubing to any vehicle, superman syndrome sets in ;)

Use of a 5 point wont necessarily keep him from a head pop with a full cage. In a big wreck, the body moves quite a bit, even with the harness'.
July 8, 2008 9:55 p.m. NYG95GA Dork

A full cage obviously poses more of a danger to the unprotected head than a bar well behind the headrest, which is why I feel the 4 point bar I use does not require a helmet during DD duty. If there were bars running right next to my head, I doubt I would feel comfortable with it.
July 8, 2008 11:26 p.m. oldopelguy HalfDork

On the Kadett, with the stock, very tall seats, there's over 6" between my head and anything hard on the roof. If the halo bar fits anywhere near reasonably it'll be almost a foot away from my head and completely unreachable without metal deformation once I'm strapped in. Racing seats will only help.

The question is not one of whether or not to install the cage, I've weighed the options and a cage will be installed. The question is whether a DOM one built to SCCA specs is enough "better" than a mild steel one built to NHRA specs to justify the cost in a vehicle that'll probably never see an SCCA road race.
July 9, 2008 12:15 a.m. MrJoshua Dork

Not worth the extra dough in my opinion.