Roll bar: how to?

First, get the rule book for the racing you want to do. It should have the required specifications for the roll cage and mounting. Go to an event and ask for advice from the tech guys themselves. See if you can find examples online of roll cages/mounts for Beetles racing in the same type of event.

I will say the rear bars in your picture are unlikely to pass inspection because they don't go to the top of the hoop. And being a "show bar" it may not be the correct material, thickness, or diameter to begin with.

Ah the MADNESS strikes again.

 

Ed,

 

Justin has it right.  Racing organizations have raised bureaucracy to an art form.  I would be very surprised if any bar or cage, not purpose-built, would conform to specs.  Ideally, one would study the rules of a racing class that interests you, then build the car to conform to those rules.  Of course, that eliminates 90% of the real world drivers, who have the car first, then need to determine what class(es) in which it can be raced.

 

Moreover, proof of compliance is often left to the car owner.  If an official questions metallurgy, weld type or penetration, it is up to the car owner to prove compliance.  An experienced, local roll/cage builder can reduce compliance concerns.

 

Be prepared for additional concerns regarding replicas.  An authentic TC, TD, or TF (or 356 for that matter) would stand little chance against a modern replica with a contemporary engine, brakes, and suspension.  My suggestion is that you ease into it, kinda like having a new dentist give you an exam before you trust him for that root canal.  Go to a couple of events and root around.

I don't think that SCCA  rules would apply to a VW powered TD replica (or any other formal organization that I can think of).  The same for our speedsters.

 

Best to put the roll bar in, and participate in some informal gymkhanas or hill climbs with like minded people, i.e. those who just want to have fun.

 

Your car is a replica of the TD in the link you provide, so make your rollbar a replica (but a safe one), and enjoy yourself.

Thanks, guys. I know the legs have to be cut off and re-done from the top. And, Greg, the point is explicitly not to make a mouse trap.

 

I checked with a colleague who is caging his TDr for hill climb. He says that's a no-go without a windshield bar, rules-wise. 

 

These cars can race but they get classed as "unlimited" because, as replicas, there's no standard car to fit them to in the rule book. 

 

So it's Like Jim says: you purpose-build a chassis with cage or you don't get to race. In Bill's case (he's the other TDr) he's making an exoskeleton. The whole cage runs outside the tub. Removable, at least, if not exactly elegant.

 

So my 5-point idea looks like it won't work. I still might make a removable 4-point system if I can figure a way to make it strong enough to actually work in a roll. 

 

Still listening to you-all for ideas and advice.

As mentioned above, rollbar rules change from track event to track event.  In other words, what will pass at one event may not pass at another.

Case in point:  When I took the training sessions for my novice racing license the roll bar on my V8 powered Miata didn't pass the 'broom handle' test (a resting broom handle, on the windshield header and the roll bar, must clear your helmet while sitting in the driver's seat). 

I eventually was able to take the course in my Miata by putting on my fiberglass hardtop....go figure.

Since then I've tracked my V8 Miata at a number of track days and have never been turned away.

I suspect that to pass tech inspection you would need to have a four point bar and be able to show the tech guys that your bar was mounted (welded or bolted) to your vehicle's frame.

Not sure about your windshield, though. 

SCCA rules, circa 2000, for any open topped vehicle state that the height of the inner bend of the rollbar must be a minimum of 2" above the top of the drivers helmeted head when seated. It must have at least one down bar to the front of the vehicle at or near the bottom of the front cowl. The roll bar must be structurally frame mounted and preferably welded in place, at the minimum grade 8 bolts/nuts must be used. The roll bar must be a minimum of 1 3/4" od with a .95 wall thickness. This is for the amateur class 1.  

 

One other thing, each SCCA event, even on 'open track days' may often have additional rules above and beyond the standard rules that must be adhered to for each class racing that are set by the event organizers.

GR, 

 

I think you mean .095 for wall thickness.

a true roll bar should be supported from the rear and have side bars along the driver and passenger seat/doors. Here's a link to RLR who makes several for vw bugs. 

In building one for a speedster the rear supports would need to be two piece in order for one to remove and install the trans. The RLR rollbar mounts to the trans cradle mount. The challenge on a speedster is not to make it too tall but still be effective. most rules require six inches min from the top of the helmet to outer edge of the roll bar tubing. In a rollover if your belts are tight your body and Belts will stretch at least 6-10 inches.   The RLR website is.  http://ronlummusracing.com

Yes, you are right. forgot to add the 0

Ed,

I noticed the "Last Open Road' sticker on the rear of your car.  What a great series of books. That and the fact that I love European cars of that era makes me wish I were born to see some of what the author writes about.  At least we can try to capture some of the feel with our replicas.....

Amen to that, Frank. Just about 7/8ths through "The 200mph Steamroller" right now. "Fairway Ferret." HAR!