Hot Rods Do you have or plan to install a roll bar in your hot rod?

Looking at both of the '55 Chevys and the way they rolled , anyone think it could have had anything to do with the soft independent front suspension, I've seen a lot of straight axle cars get out of shape but they never seemed to dive to one side or the other. HRP

 

In the first one the driver looked like he was trying to avoid a collision and then lost it unfortunately.
To bad, it was a nice car. The second one, the car appeared to me kind of cobbled together. The driver seemed unwilling to get out of the throttle and thats what happens.

 

Only attached to the frame. If bolted I’m fairly certain it will require backing plates and Grade 8 hardware, if welded should be done by someone you would trust your life with.

 

I had a full legal roll cage in my 30 A 2 door when I was autocross, rally and road racing it.
I took it out because I am going to sell the car. The car has a boxed frame also.

 

No. Its not a race car. Its a highway cruiser.

 

It's a Chrysler coupe, but yes welded to the frame of the car. Front pads of the swing out side bar also.

 

I don't have any dedicated race cars, but I have a couple of street/strip cars that are quick enough to need cages, and they have them. I would not install one in a full body car that does not need one. A roadster...hmmm....I'd have to think long and hard about that, when the time came. Maybe that's one of the reasons why I don't have a roadster?

 

I understand your sentiment HRP. It was a huge step up from what I had originally. This end result was more out of practical necessity than looks. It clears my head with the helmet on.
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Most rules require a minimum sized plate as a footprint.

What you do is leave the plate until last, and have a hole for the tubing to slip through [to drop the cage down and weld the top side of the cage]
You then lift the cage up and slip the plates underneath and weld the cage to them [and stitch weld or bolt the plate to floor]
This is a common construction method on FIA type roll cages

 

That there is a great idea. Sure would stiffen the chassis.

 

Can't fit one in my car and me too. 6'3", 270#, I barely fit as it is.

 

Thanks!

 

See, that is my point. You thought out your plan and put your safety first. Doing otherwise just does not sense in any for or fashion. Good on you.

 

Is it used on cars with unibodys, not frames? Because if the car has a frame (like all old hot rods do), you need to weld the tubes to the frame, not to plates welded to the floor. And this method won't work.

 

In the 70s and 80s I worked for a trampoline manufacturer in their chrome plating department. The tanks were big enough to chrome plate half of a trampoline frame as a one piece unit. At the time the tanks were the biggest plating tanks west of the Mississippi River. We plated a few full car frames in those tanks and I lost count of how many headers we plated.

 

Although not applicable here, it is very common in FIA affiliated classes. Low height door intrusion bars are used as pseudo subframe connectors etc. The rules usually don't allow bars to go past suspension mounting points [to allow for crumple zones]


I've seen the results of a 70mph hit into the drivers door of a stationary car[in a class that had a standardized cage design]
This particular car didn't fit their design [but exceeded it] which saved the drivers life.

Their rules required an "X" design in the door bars which requires cutting and welded. What the builder did instead was bend the top door bar in a "U" shape and the bottom bar in an Upside down "U" shape and weld them back to back into an "X" shape.
The builder also had seat mounts attached to the door bars, so when it took this massive side hit the whole assembly shifted sideways and crushed the drive tunnel [instead of the drivers seat]


We had another incident with a rally car , where the cage and seat were built like a "capsule" BUT the rear shoulder harnesses were attached to the floor.
During a rally the rear wheel caught on a tree and ripped the car in half. The rear seatbelt anchors stayed with the rear half, and the Navigator was crushed to death by his own seat belts.


With Safety you are always chasing the weakest link.
As roll cages get better, the old 2" diagonal belts are the weak link.
So 3" 5 or 6 point harnesses are now normal ,and the driver's Neck is the weak link.
Now neck braces ,and lately HANS devices are mandatory.

But the saddest thing to evolve, is Liability laws [insurance and lawyers are now taking the sport away from the common man]
The man that is trying to save your life is probably the one that faces legal troubles.

 

I think he means it gets welded to both the frame and the floorpan. Slide the plate up the tube, weld to the frame, then slide the plate down and weld the plate to the floorpan.

 

I got the idea that the whole cage was slid down (past the floor) and the top of the cage welded together, then the whole cage was slid up, and the plates slid under the cage tubes, and the tubes and plates all welded together and to the floor.

but I could be imagining things he didn't actually write. Because that does sound like a great way to put a cage in a car that does not have a frame that you have to weld the cage to.

 

Just so you fellows know, @Mimilan is actually a she.

 

This is exactly correct. I've seen many cars put on the trailer because the cage wasn't fully welded on the top

Technically yes! I was just throwing ideas at how to fully weld the top of the cage on closed body cars [especially if the cage follows closely with the roof]

I'd be curious as to how the rulemakers interpret this on cars like Tri-5 Chevy's where the frame is narrower than the body, and the cross braces are part of the floor and not the frame.

 

When I put the roll bar in my 55 Chevy, I bent the ends of the main hoop inward at the bottom, and welded them to the frame. The side bar, I also bent towards the frame under the floor, and welded it to the side of the frame rail. I expect there are other ways to do it, and I'd also be interested in seeing some of the other ways to do so.

Welding the top of the cage together when you can't drop the cage down, can be interesting...I don't have the skills necessary to fit a cage closely. Fortunately the few cars I've installed cages in have had other opportunities to make it easier to weld the top--such as being more traditional race cars, where the cage is not expected to be "form fit" to the body--rather, it is noticeably smaller than it could be. Like they used to do, in the old days.

 

My 57 ford is like that, frame narrower than the body. For the side bars weld 2x3 out riggers to the frame and tie into the inside rocker. Then weld to the outrigger.

 

Re: Mimilan’s comment about liability lawsuits, that is why I quit doing rollbars at my shop, even NHRA certifiable kits. All it takes is one knucklehead and his lawyer and a small shop owner can lose everything. Of course these days they sue everybody who ever touched the car.
I’ve been going back and forth about building a rollbar for my ‘28 roadster.


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If the car will run quicker than 11.50, a roll bar is required, I installed this in a buddies, chopped 32 sedan. It is bolted to top of the frame rails in 6 places, with 6" plates, and has removable side bars. The plates sit flush on the rail with an added plate with gussets along the side of the rails. It also had 2 sleeves on the rear uprights, for headrests to mount. It's all removable, and allows the car to run 11.00, as it should, with a healthy BBC. He is planning on installing a tonneau cover inside. Good chance the car will be at GNRS !

 

Our OT race car had the roof removed to install the cage.

 

Planning one in the plymouth.

 

One thing I can tell you, chassis flex isn't something that I ever paid much attention to. It was just part of how a car moved.
The cage makes it a sturdy box. Certainly, a full tube chassis would be absolutely rigid!

 

Where a roll bar really shines is in a uni-body type car, but be careful as to the process used when installing as it can effect how the doors close especially after everything has already been aligned.
I noticed a slight resistance at the latch on my driver side door when shutting after putting the roll bar in my Nova.

 

Two ways to weld roll cage uprights to a "C" type frame ( say a Chevelle factory frame is one) to the top of frame rail or two) hole saw a hole through the top frame rail and slide pipe to bar tubing to bottom rail and weld bar to to top and bottom rail . Of course easier to do on a race car where you are putting in a floor.

 

Now I had a 1962 Chevy ll and we put a Chevelle frame underneath all the way back to the front of the rear spring hangers. Welded a thick plate to the back of the frame and used bolts to mount to rear spring front mounts and then bolted body to frame. Car hooked up on the pavement great. Gave you updated front suspension, steering and brakes over the factory set up. Now , I think that way would still be better than the aftermarket sub frame they have out now that still bolts to the factory front suspension points. Especially without frame connectors or even frame connectors. Now , bolt in or weld in frame connectors is a whole other subject.