Must roll cage be bolted to frame to offer decent protection?

Must roll cage be bolted to the frame in order to protect in a roll-over? I am going to build a cage for my civilianized M-38. I'll have downtubes with angled bracing behind each seat plated to the top of the rear wheel wells and then front downtubes left and right on each side of the dash, plated to the floor and perhaps bolted to the dash too.

I am not a serious off-roader. Just lookin' for protection if she rolls once or twice. Any advise is appreciated.


Jordan

 

Jordan
You do not have to tie your cage to the frame for roll-over protection if you have solid floors/sheet metal. Plates welded to the bottom of the tubes, quality bolts (grade 8 )through the
floor and plates on the bottom side is sufficient. Remember it is best to cut the sandwiching plates different sizes so they don't "work" the sheet metal or tear through the floor in a roll.
Best of all KEEP IT ON IT'S TIRES!!! R)

 

Thanks for the help guys.

 

Basically what they said. For the average user to solid sheet metal it will offer fair protection. I used to race my '59 CJ-5. Endo'd and side rolled on hard pack. The cage protected me. Cage was trashed but I was protected. Still running the same tub. If it were a 55 mph endo on the highway probably would have been different but for trail use a basic well designed cage Would be fine. The cage was bolted to the tub as said above.
If an all out race rig or one that sees use where multiple rollovers are a possibility I'd tie to the frame and make sure the sheet metal is solidly mounted as well.


Sent from my iPhone using Tapatalk

 

My CJ5 suffered a rollover on the highway at about 40 mph. It just had the stock hoop type rollbar bolted on the rear fenderwells. The driver walked away with no major injuries-that rollbar really did it's job!
One thing I've read is to round the corners on the reinforcing plates under the body. This will reduce the chance of tearing the sheetmetal in a wreck.

 

I did an endo with just the fender mounted roll bar in my CJ5 at 55 mph. Not only did the bar not come loose, I could find no warp in the bar and am still using it 40 years later. It did loose a lot of paint and the fronts of the wheel wells ended up about 2" shorter along with similar depression at the tub rails. As a side note, the CJ5 received all new sheet metal and is the one in my signature.

I did frame mount the bar in the 3B and used heavy rubber/steel spring shackle bushings with grade 9 bolts so things can flex a bit. That one has not been live load tested.

 

Thanks everyone for the input.

Jordan

 

I think tying it into the frame is the correct way to go, but tie it in like you would the body. I am going to tie mine in where the body bolts to the frame, such that hit has the flex points with bushings.

 

I'm going to tie my cage into the frame. I like to wheel my early cj and even with the frame mostly boxed it it flexes. I don't want to deal with the old frame cracking and then breaking, so I'm going to stiffen it up more with the cage.

 

I want to tie my cage into the frame. If I ever roll it at highway speeds, I want to live...
Not saying the other will kill you but I like the additional protection.

 

I have a stock jeep roll bar from a later CJ5. I have a fiberglass body. Anyone have any experience installing the roll bar? There are after market frmae to fender kts. These kit need to be welded. Just wondering if anyone has a simpler solution. I dont belive that fglass will hold up in a rollover.

 

Might be just as easy to have someone bend up a new frame mount bar. I agree with Chuck-I would never mount a bar to glass.

 

I agree. I am concerned about flexing and ultimately cracking of the tub between the mounts from the frame and the tub. I thought about putting rubber between the bar and tub then rubber between the lower mount/plate and the bottom of the wheel well. I guess you could call it sandwiching but it would be supported by the frame and would hopefully cushion the connection. I would then bolt the bar through the tub and rubber into the frame supported plate under the wheel well. I rarely ever drive this thing over 35mph but nevertheless fell better with a roll bar on the jeep.

 

If a guy ties into the frame, are there any techniques for welding to the frame to avoid weakening it? That concerns me a bit. The other problem is the jeep is all painted and finished. Guess a guy could rattle can the frame welds and also hope the weld heat does not burn off the undercoating on the tub.

Jordan