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How did you mount your roll bar?

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I'm a little puzzled as to why you'd mount a roll bar that won't offer any protection, but to each his own.

The roll bar in my Miata is mounted through the carpet to substantial backing plates. I cut the carpet for fit snugly around the uprights. If you are concerned about aesthetics, consider whether the upright poking through the carpet is uglier than the mounting plate squashing down the carpet. There will be holes in the carpet from bolting in the mounting plate (usually 4 holes per plate) vs 1 bigger hole for mounting the plate under the carpet.

If you are planning on running the car at a track day, check with the organizers re regulations. Rules for track-worthy roll bars are very strict, and certification of the bar is often required, as well as regs about the relationship of the bar to your head.

If the bar is just for style, consider what is known as the mousetrap effect. If you roll the car, a style bar can collapse like the bale of a mouse trap, doing more harm than good. Also be aware of the relationship of the bar to your noggin. A bar that sits directly behind your head becomes a hazard in a rear ender, as you split your melon on the bar.

Worried yet? Bet you never thought a safety device could be so dangerous! /ubbthreads/images/graemlins/laugh.gif
 
That looks OK for a street bar, very similar in mounting style to mine (though with less cross bracing). If you are using padding for the 'cracked melon' problem, it is best to use SFI rated padding, available from places like Racer Parts Wholesale, SafeRacer, Hard Dog, etc. The typical soft, squishy foam won't adequately protect your melon in a crash. If your head is well under the bar, or > 6" ahead of it, you're probably OK.
 
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I'm a little puzzled as to why you'd mount a roll bar that won't offer any protection, but to each his own.


[/ QUOTE ]
There has been a thread on "cosmetic" roll bars for MGBs going on for several weeks over on the MG forum. Probably should check it out.
 
Use backing plates for all mounting and bolts and padding, bolt it to the metel (not on top of carpet), its better than nothing. You might consider welding in a cross support, horizintal behind the seats would be fine, this would help brace it and allow a place to hook up a shoulder harness. If you roll it at least something will be over your head----"Mouse Trap" I doubt it.
 
I agree that something over your head is better than nothing but if, and only if, it is properly braced and installed. I would use oversize backing plates directly throught the metal (not through the carpet). If you can continue to the frame, better yet. The bar should have a brace from the lower portion of one side to the upper portion of the other side. Grade 8 hardware too.

Your bar has aft support but no fore support so you might consider a triangulating towards the front. You can add a brace from the top of the bar across the passenger seat to the front chassis mount.

But, I am thinking of adding door bars to mine that attach to the hoop, half way up and run forward between the seats and door and attach to the front chassis mount. This should keep the bar from mousetrapping if you do ever roll over (which I doubt would happen anyway.)

Maybe should have started this thread before powdercoating. oops.

see this site for ideas https://autoweldchassis.com/opts.ivnu

Don't attach a harness directly to this kind of bar unless the bar is secured to the chassis directly.
 
Hi Larry,

That bar of yours is identical to the old one that was in my TR4 until recently. I'm replacing it with a more substantial unit, taller and fixed to the floor/frame, to comply with racing rules, provide greater safety and give increased chassis rigidity.

But, I'm *not* suggesting not to install the one you've got there and I gotta slightly disagree with any folks who say "street" roll bars like that one are useless and discourage their use. I think they provide some increased margin of safety, even if it's not a whole lot. Even a "street" bar is more substantial than the hoodsticks!

"Street" bars are sized for height and width to allow the top to be raised and lowered. In order to fit a "properly sized" roll bar, the car would be committed to toplessness. (The taller/wider custom roll cage going into my car will be fitted under a hard top, so this isn't a concern.)

Even with a "street" bar, you might find that raising and lowering the convertible top is just a little trickier. I did.

Just don't panic if the hoodsticks don't quite clear the roll bar in the usual relaxed or de-tensioned position. The "trick" to raising is to lift the hoodsticks behind the bar, because they might not quite clear until tensioned with the lever at the b-post. If this is the case, temporarily tensioning them until the two forward sticks are postioned ahead of the bar does the trick. Then just release the tension until the top is secured all the way around. Once the top is fastened, tension it as usual. Really it's only a minor, extra step that becomes second nature after a while.

Back to your question, though. My bar was installed over the carpet (previous owner). I would definitely not do it that way again. In my opinion, the ideal would be to remove the carpet and have it properly cut and trimmed to fit nicely around the base of the roll bar. Maybe some hook and loop fastening (Velcro) or snap fasteners could be used to keep the seam closed around the base of the roll bar. In my opinion that would give the nicest and cleanest look. But, more importantly, it would allow the carpet to be easily removed for cleaning or if it ever gets wet. The latter is of particular concern, because if the car ever gets caught in a rain shower with the top down, or a little water gets inside during it's weekly bath, the carpet under the bar mounts can get wet and might stay soaked a long time, promoting rust. Also, if not carefully sealed, it's possible some splash might find it's way to the carpet, up from below, around the mounting bolt holes.

The heavy mounting plates and bolt heads might make for a pretty lumpy appearance of the carpet, right around the base. A layer of padding under the carpet, much like is used on the floors of our cars, could help that a lot by slightly raising the rest of the carpeted area to be more level with the bolt heads.

I agree strongly with the suggestion to install some padding on the roll bar to protect noggins, and maybe even a head rest type pad on any car where lowback seats are used. Also don't bolt anything to the roll bar, such as a shoulder-style seat belt, anywhere around head height. (I speak from bad personal experience about both these items.)

/ubbthreads/images/graemlins/cheers.gif
 
Does anyone have suggestions for a TR3 roll bar for vintage racing? I would most likely be racing with the corenthians in Texas, but would like to install something that would be legal in other groups as well.

Thanks,
 
Greg, your best bet would be to get a copy of the rules of whichever group(s) you plan on running with, and see what the requirements are. As the Chief of Tech at Waterford Hills, I have had to disapprove cars that have showed up with a non-compliant roll bar or cage, simply because the owner didn't do his homework.
Jeff
 
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