Rollbar Advice/Regs, Please
 

Sorry if this is redundant, but I can't glean this from past threads.

Being a Club Cranky wannabe, I've got to redo my SPFs rollbar to pass muster. I've found someone with significant rollcage fabrication experience that *thinks* he can do a full width rollbar for track that could be switched off with the stock hoop for street.

I realize the Oltoff group have done some work here, but it's hard to get details and they're far from Cincinnati.

So, I need some sort of regulations. I know there's the full width and two inches above helmet. And I've found some steel composition and wall thickness data from the web.

If it matters, I most want just track time, not wheel to wheel racing. After all, I've SEEN RacerX in full cry and can't imagine being in his way...

But anything you could provide to help with regulations for track events and any other practical advice would be very, very welcome.

Thanks, all. I promise *after* pics when this gets done.

Doug

I had a similar problem. Here is what I did! First get yourself some 2.00 diameter d.o.m. tubing .125 wall .Go down to your local midas muffler shop they will bend it for you at a reasonable price. You need to make some .500 x 3.00 steel plates one gets welded to the rollbar the other gets bolted to the floor right over the frame thats important as it must withstand the weight of the car.You also must have at least 2 other cross bars triangulated so that they form a pryamid .Note these 2 other bars must bolt to the rear bulkhead and,then down to the main frame.I spent about 400.00 in materials plus the bending this also included powder coating the frame. I suggest going to a machine shop in your area to fabricate the plates.Any thing less I would not suggest ,after all its your life on the line.


Regards
tommachine73

ttt

Doug,
Call Bob or Dennis Olthoff direct and ask them your question. I did that yesterday and was told that a driver at 6'-0" as a rookie didn't need to raise the rollbar if not going full out on the track. I suggest you check it out for yourself and your own situation. They have the extention setup if you need one.
TL

Doug,

Here is a excerpt from the SCCA General Comp rules.

GCR - 144
ROLL CAGES
These general specifications are for all automobiles. Roll cages are
required in all automobiles.
Roll cages may be of two (2) designs, low front hoop (top of steering wheel) or high front hoop (top of windshield). Specific installations are subject to approval by the Technical and Safety Inspectors at each event.
The Technical Staff of Club Racing shall have the responsibility to ensure specification compliance with SCCA safety standards. To that end, the Technical Staff of Club Racing may or may not accept alternate construction standards from any source that significantly vary from SCCA standards of protection.

18.1. BASIC DESIGN CONSIDERATIONS
1. The basic purpose of the roll cage is to protect the driver if the car turns over, runs into an obstacle such as a guardrail or catch fence, or is struck by another car. It shall be designed to withstand compression forces from the weight of the car coming down on the rollover structure and to take fore/aft and lateral loads resulting from the car skidding along on its rollover structure.
2. A system of head restraint to prevent whiplash and rebound, and also to prevent the driver’s head from striking the underside of the main hoop shall be installed on all vehicles. Racing seats with integral headrests shall also meet this requirement and have a support to the main hoop. FIA homologated seats need not have seat back attached to roll structure if seat manufacturer
recommends, within their mounting instructions, that seat back
remain unattached to roll structure. Competitors shall have
manufacturer recommendation in writing. The head restraint on
non-integral seats shall have a minimum area of thirty-six (36)
square inches and be padded with a non-resilient material such as Ethafoam® or Ensolite® or other similar material with a minimum thickness of one (1) inch. The head restraint shall be capable of withstanding a force of two-hundred (200) lbs., in a rearward direction. The head restraint support shall be such that it continues rearward or upward from the top edge in a way that the driver’s helmet can not hook over the pad. The padded surface shall touch the helmet; it shall not be under fiberglass or other hard material. 3. Forward braces and portions of the main hoop subject to contact by the driver’s helmet (as seated normally and restrained by seat belt/shoulder harness) shall be padded with non-resilient material such as Ethafoam or Ensolite or other similar material with a minimum thickness of one-half (1/2) inch.
4. No portion of the safety roll cage shall have an aerodynamic effect by creating a vertical thrust.

5. Roll cage or chassis design shall prevent engine intrusion into the driver compartment.
6. Material:
A. Seamless, or DOM (Drawn Over Mandrel) mild steel tubing
(SAE 1010, 1020, 1025) or equivalent, or alloy steel tubing
(SAE, 4130) shall be used for all roll cage structures. Proof
of use of alloy steel is the responsibility of the entrant.
B. Minimum tubing sizes (all Formula, Sports Racing, GT, and
Production Category automobiles, and all automobiles
registered prior to June 1, 1994) for all required roll cage
elements (All dimensions in inches):
Vehicle Weight Material
Without Driver Mild Steel Alloy Steel
Up to 1500 lbs. 1.375 x .095 1.375 x .080
1500-2500 lbs. 1.50 x .095 1.375 x .095
Over 2500 lbs. 1.50 x .120 1.50 x .095
1.625 x .120
or 1.75 x .095
C. Minimum tubing sizes for (all Showroom Stock, Touring and
Improved Touring Category automobiles registered after June
1, 1994) for all required roll cage elements (All dimensions in
inches):
Up to 1500 lbs 1.375 x .095 DOM / Seamless / Alloy
1501-2200 lbs 1.500 x .095 DOM / Seamless / Alloy
or 1.500 x .120 ERW
2201-3000 lbs 1.500 x .120 DOM / Seamless / Alloy
1.625 x .120 DOM / Seamless / Alloy
1.750 x .095 DOM / Seamless / Alloy
or 1.750 x .120 ERW

Hope this helps, I can send you the entire text and DWG's from the GCR if you would like.

Just send me a email with your needs and I can forward.

The Olthoff's have 2 options. A taller driver side bar, and a taller full width bar. I can't see why you would have one fabricated/engineered when somebody who knows the car well has already done it. Why try to reinvent the rollbar... uh I mean wheel? Plus, you have a nice car, why go out of your way to bugger it all up?

John
spf1421

Dennis Olthoff just finished up the full width rollbar on my SPF, it is a stunningly perfect installation, strong, handsome, and absolutely first rate construction, right down to the polished welds.

I agree, have someone who has done one (or many) do your car up right. I wouldn't want someone learning on my car.

thanks
 

Gents,

Thanks for your replies. You know, if the folks at Dynamic Motorsports here in Cincinnati had a better relationship with the Oltoff group, I wouldn't be looking for a local fabricator here in Cincy. But every time I ask about this topic, I get the shoulder shrug. Every time. And this is not the first time that sort of thing has come up. Too bad.

Now I guess I could have the car shipped to Oltoff-land and done up, but man, that's expensive and I loose my car for longer than necessary.

Hal: can your new rollbar be switched out with the old one? I'd like that option as I do like the original look.

Richard: Wonderful stuff. Thanks.
Doug

Doug,
I have a full width roll bar that was installed by the Olthoffs several years ago. I believe it is the same as what they currently offer.

I don't think taking it off and putting the original hoop back on is very practical. There are two holes drilled in the body for the posts on the passenger side. The hole for the downtube behind the driver's right shoulder became a place to mount a battery cut off switch when my car's roll bar was installed. I don't know what you would do with the holes on the passenger side if you took off the full width bar.

I changed my rollbar by adding a cross tube just above the rear cowl. This was done to raise the anchor points for the shoulder straps. The original mounting points for the shoulder straps was way to low IMHO. I moved the battery cut off switch of course. Hope this and the photos help.

This bar fits just under the rear hoop for the soft top allowing you to still use the soft top.

FWIW, the car looks "orginal" :rolleyes: when I am driving it. :D At least I can't see the difference from the driver's seat. :cool: