Roll Bar design

I am planning on putting a roll bar into my speedster. Once the new power plant is installed i think it wise to fit one. I have looked at some of the pics of the old race cars but i am not crazy about the design. Any body got any ideas.

Functional roll bar: will need to be tied into the chassis via a three point mount. It can be done but requires some fiberglass cutting and additional metal supports.
If it's more of a show bar you are looking to do, there are a number of options that are inexpensive.

It all depends on if you want a "show bar" or a roll bar. A show bar is purely decoration and typically just a hoop or two, where as a Roll Bar has triangulation and is braced against the pan or tube frame in various spots with bars that come forward into the passenger compartment. The purpose of the "forward" bars is to keep the Roll Bar from Collapsing should you invert 180 degree's

I am going to go with a boxster style rollbar - painted not chromed. subtle, functional and looks much more aggressive than the CMC standard decorative hoops.

http://www.986faq.com/4-0/xmy-1.jpg

I'd suggest evaluating what you want to do with the car as one factor in your decision, but also I'd look around at the traffic you're keeping company with.
One hit, and BLAMMO. Most of our cars are toast. If you can be Miyamoto Musashi about driving and assume you're already dead in a crash, you don't need roll bars at all -- so cosmetic ones are fine. If you drive like an idiot -- as I've been known to do -- you might want a little more protection from lateral hits and mud-grabbed-my-sidewalls-and-now-I'm-upside-down stuff.
I'd suggest that the roll bars be tied in at the same three pionts as everyone advocates here, but also that there be no chance of your head being mushed by the bars if you're hit hard or flipped.
The PCA advice for these cars is not to put them in street cars of the 356 design at all:

http://www.356registry.org/Tech/roll-bars-in-street-cars.html

I went a little nuts. Unless you live in the Valley of the SUV -- or drive like I do -- it's probably overkill.

If your looking for protection and safety ...Forgettaboutit. A pan car is not really designed for a roll bar. I have built plenty of chassis for late models and sprint cars... I know what I'm talkin about. A Bug with a roll bar .. first point of compression .. the body structure. Secondary.. the roll bar. Compaction and momentum are the key factors of impact.I have survived a 160+ mph impact straight into a wall in a chassis I built with only a few bruises from the seat belts.All I have to say is ...You'll really have to spend a lot of $$ on the pan chassis to make it work. Go with the show bar.

Simple show bar with minor mount alterations from a Miata for $175.

who sells the show bars, interested in perusing all the different models.

You'll need some padding or distance between your head and the bar. In a rear end collision your head will snap back and forth and open up like a hard boiled egg on the roll bar.
ed

Does anyone here have some decent looking padding on their CMC show bar? I kinda want to put mine back in someday.

Cory, where is the Bushido driving school?

You are getting the straight skinny here. Done right, and that is the only way I think it should be approached, you could lift the car from one of the roll bar hoops. Triangulation, stout tubes, good welding. I personally like the Boxster look also, and believe one could apply a padded cushion in the hoop to give you some whip-lash protection. I have some pictures in my gallery, I think, of a roll bar done rather well, w/ padding and plenty of bracing. If those pics are not in there, I'll post 'em up from files here.

Just a word of caution. Roll bars with padding work great if you're wearing a helmet but,,, I've seen it way too many times when I've handled traffic accidents that when your head hits the roll bar with padding, the padding compresses and it's virtually just as hard as if it were not padded. The padding works best if you're wearing a helmet. Additionally, many people lull themselves into a false sense of security with a roll bar and often times with a fake roll bar.

My suggestion is to make sure the Roll Bar or faux roll bar is far enough behind your head so that no contact is made, (padded or not)

This is getting gruesome. If my head is snapping backwards hard enough to hit some foam-padded steel and suffer concussive damage, wouldn't the damage to my neck or spine be just as severe if there was nothing to stop my head?

Moral of story: headrests are good to have in a rear-ender. Also everyone should upgrade your 3rd brakelights.

stephen a,

Here's a photo of a paddded (fake) CMC rollbar. Note the third-brake light mounted to the underside and lighted via a wire run within the rollbar, this makes it more visible because it puts the light up high and it also shines through the rear window when the top is up. (I later realized it would have been easier to run the wire under the padding). The padding is installed with black vinyl tape (various colors are available) and wire ties. I don't race the car, just like to have it look that way. This is a pan-based car so didn't try to install a real rollbar, figure these things are about as safe as a motorcycle anyway.

ECB

Bruce,
I would love to see your car sometime. I live in VA and hope to build a outlaw sometime in the next year - love your look.
Dale

Stephen A, No it's not guresome but some straight facts during the decision process of "do I install a real/fake roll bar."

Yes, If your head did snap back then you'd probably be seriously injured (that's why the HANS device was developed) but, in many collisions, just a tap is enough to make your head move and if it hits a padded or un-padded roll bar and stops abruptly, then the chances of a skull injury are great and, maybe no injury other than whip lash would have occurred had the roll bar not been there.

It's all a big roll of the dice but if you can shave the odd's that are against you then you have a better chance of winning

The shots of a sturdy roll bar welded in. Also a Photoshop insertion of a boxster roll bar in a Speedster. FYI

Kelly, I have to disagree to the statement that it's a sturdy roll bar. The top of the roll bars are un-supported and the leverage on the top of the bar could easily cause the hoops to fold under. To make it a "real roll bar" I believe it needs triangulation starting at the upper portion of the hoop with as great an angle as you can get on the triangle brace bar.

See here for an example: http://www.teammiata.com/mall/Boss_Frog_Roll_Bar.asp

Did you ever see guys racing the older cars at vintage races without rollbars - open wheel, elevation changes, full out arournd sharp corners, etc. - wow, that takes big ones! I'm also always surprised to see the nuber of top down autocrossers running without rollbars. Nothing to do with installing rollbars, just a couple of observations.

Dale - Thanks for the compliment. Come to Carlisle in May and see alot of nicer cars.

ECB

I have been sporting a lumpy skull for 30 years from contact with the roll bar in one of my early Tigers. Needless to say the current Tiger is sans bar, as will be the Speedster.

Robert,

How about posting some updated photos? Your last posted drawing shows an integrated rollbar.

Picture of cosmetic dual bars in speedy. Sorry for the quality... camera phone pic. I have other shots on the office computer. Cosmetic, SCCA, rigid street, etc... Will try to get some up first of the week.

The 356 Reg article is a good one, Cory. I refer people to it all the time.

For us, the dual hoop is the most popular for street use. The track guys aren't generally concerned about looks first... which some of you may have noticed in the Blow It Up spyder. :)

Carey, I agree that your brace-at-the-op is stronger by design. The ones braced lower down will not be as strong, but they very well may be strong enough. What we really need here are pictures of crashes w/ roll bars of different designs. That would settle the discussion pretty proper.

Wow Guys, I would never have believed that this thread was going to generate so many replies! Thanks for all your input. I never gave it much thought about my head hitting the roll bar. I have installed reclinable racing seats with a high back, hopefully this will help to keep my head away from the roll bar, I do understand if I have a seriuosly big prang I wont be around to see the dents in my head but I guess I am looking for a little protection from those gentle roll overs that could occur while playing on a skid pan or autocrossing. The main reason is that I need a secure mounting to fit the 4 point seatbelts, I have yet to see a speedster with three point retractable seatbelts that work without fouling the softtop.

I would also admit that I am partial to the looks of a pair of nice thick chrome hoops (polished stainless is even better.)

I have posted a picture of the car with seats under my pictures, I am not sure how to ad a thumbnail to my posts.

The triangular downrigger from a hoop into the structural metal of the car can probably be accomplished five or six different ways, but I've got to say I think there might be bigger issues for a VW-based car like a CMC.
When we dismantled my car, there were remnants of three pans in it. The seat belts were held in to the floor with 1/4-20 bolts, and the pans were rusty around the bolt-holes. If I had been in a wreck, I'd have been ejected for sure.
That doesn't even begin to cover the condition of the pans elsewhere. That was the true catalyst for the re-do of the whole works.

I found this image today. It's the best overall shot of my car's CMC body without any modifications.

Here's a pair of shots from one of the "cosmetic" bars.
This particular set was made removable, and they are firmly attached tot he main 3" tube rails and torsion housing, BUT I would still not bet my life on them...

Carey, Nice color on that car . . .

Thanks. It's a custom color I mixed up a few years ago using the BMW Merlot Red Metallic and removing the flake. Unfortunately it is a NIGHTMARE to spray... VERY, VERY poor coverage. Anyway, it has been a standard color ever since.
You are looking at one of the LAST Merlot cars (I think I have 4 more in queue)... we decided today (literally) that it will not be in the '08 line-up.

Obviously, I like the Carmona Red Metalic, a Porsche color that is readily available, I suppose. Have no idea how much trouble it may be to spray, but when done right, it is awesome, IMHO. I guess you could leave out the flakes, which are very mild to my eye and really look like pearl. Believe plain Carmona Red has been in the Porsche palette for many years. Your pic (although kinda low res) looks similar, is all I am saying.

Carey:

I think there's a guy here in Beaufort who has one of those. Very different color - not quite Burgundy and leaning towards purple. Very pretty and very different (at least his is....)

gn

You know your the reason that I finally posted about my roll bar and chassis set up in my car.

From the back, the driver and passenger side roll bar hoops are ment to match that of the top edge of the windshield frame and the hoops width was to keep from having head to roll bar contact.
From the side, the rear hoop bracing bar is ment to mirror the leading edge of the windshield.

All of this took a little planning and didn

NIIIICE. Where were you two years ago?

Actually, I met you the first year that you took your car to Carlisle's car show.

My cage layout is a vast mix or many designs and I toyed with the idea of a full overhead cage..., but what you see is what...Awww you know the saying.

David: WOW! You have got it right. Not that I think Cory got it wrong, 'cause he did not. His cage is as stout as you would ever need. What you have there is obvioulsy a serious racing sort of thing. I still think there would be a way to get satisfactory crash resistance and also be able to use the doors. Is that a recent photo? Or is the car together yet? Awesome.

what about this?
not for roll/ more for (SHOW)

You better check your self before you wreck yourself! passenger has a eject button!