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IX. ROLL BAR SPECIFICATIONS:
2. Basic Design Considerations: The basic purpose of the roll bar/roll cage is to protect the driver in case the vehicle rolls over. This purpose should not be forgotten.
B. Cars with factory built or factory reinforced roll structures may be allowed in the Grand Sport Division. They will be evaluated on a per car basis. The decision of the Race Director will be final.
C. The two vertical members forming the sides of the hoop shall not be less than fifteen (15) inches apart, inside dimensions, at their attachment point to the uppermost chassis member.
D. An inspection hole of at least 3/16 inch diameter must be drilled in a non critical area of the roll bar member to facilitate verification of wall thickness. This should be at least three inches from any weld or bend.
3. Material: The roll bar hoop and all braces must be of seamless, ERW (Electric Resistance Welded), DOM (Drawn over Mandrel) or CREW (Cold Rolled Electric Welded) mild steel tubing.
B. The size of the tubing to be used must be determined on the basis of the weight and speed potential of the car.
C. On cars utilizing a full roll cage, the main hoop and support braces should be of the same size.
4. Fabrication: The main vertical hoop must be one continuous length of tubing with smooth continuous bends and no evidence of crimping or wall failure.
B. Gussets should be welded at the junction of any tubes.
5. Bracing: It is recommended that braces be of the same size tubing as used for the roll bar itself.
B. It is required that a diagonal brace be used to triangulate the main hoop, and it is highly recommended that this brace be attached at the top on the drivers side and attached to the bottom on the "passenger" side. See Exhibit A
C. A head rest is required if not part of the seat.
D. Anchoring the shoulder harness to the roll bar is recommended.
6. Mounting Plates: Roll bars and braces must be attached to the frame of the car whenever possible. Mounting plates must be used for this purpose.
B. In the case of cars with unitized or frameless construction, mounting plates must be used to secure the roll bar structure to the floor of the car. The important consideration is that the load be distributed over as large an area as possible. A back-up plate of equal size and thickness must be used on the opposite side of the panel with the plates through-bolted together.
7. Removable Roll Bars: Removable roll bars and their braces must be very carefully designed and constructed to be at least as strong as a permanent installation. If one tube fits inside another to facilitate removal, the removable portion must bottom on the permanent mounting, and the mounting hardware used to secure each joint must be grade five (5) or better. It is recommended that the telescope section be at least eight (8) inches in length.
8. Installations on Cars of Spaceframe or Frameless Design: It is important that the structures be attached to cars in such a way as to spread the loads over a wide area. It is not sufficient to simply attach the roll bar to a single tube or junction of tubes. The roll bar must be designed in such a way as to be an extension of the frame. Considerable care must be used to add as necessary to the frame structure itself in such a way as to properly distribute the loads. It is not true that a roll bar can only be as strong as any single tube of the frame.
On cars of frameless construction, consideration should be given to using a vertical roll bar hoop of 360 degrees completely around the inside of the car, and attached with suitable mounting plates. This type of roll bar then becomes a substitute for the frame.
9. Other Designs: Deviations from the above will be considered.
10. Roll Bar Padding: Roll bar padding should be used to protect the Driver/Navigator in all areas of possible contact.
11. Minimum Tubing Sizing: The size of the tubing to be used shall be determined on the basis of the weight and speed potential of the car.
Vehicle Weight |
Tubing Material |
Tubing Dimensions |
| Under 1500 lbs. | Mild Steel | 1.50" O.D. X .120 wall |
| Alloy Steel | 1.50" O.D. X .090 wall | |
| 1500 to 2700 lbs. | Mild Steel | 1.75" O.D. X .120 wall |
| Alloy Steel | 1.50" O.D. X .120 wall | |
| 2700 lbs. & over | Mild Steel | 1.75" O.D. X .120 wall |
| Alloy Steel | 1.75" O.D. X .120 wall |
X. ROLL CAGE SPECIFICATIONS
2. Super Sport Division Requirements: Bolt-in roll cages are allowed, welded cages are recommended.
B. Door intrusion bars are required on both sides of the vehicle. A minimum of one bar is mandatory and two or more are recommended.
C. Material, Fabrication and Bracing specifications are the same as the specifications for a Roll Bar. See Section IX for detailed information.
3. Unlimited Division Requirements: Bolt-in roll cages not allowed.
B. A NASCAR style roll cage is highly recommended.
C. Door intrusion bars are required on both sides of the vehicle. A minimum of two bars are mandatory and three or more are recommended. The bars should be connected in a ladder like fashion.
D. Expanded metal roof mesh is required and should be welded to the cage on all cars without an integral welded-on roof. This requirement applies to cars with fiberglass or plastic roofs, removable or sliding tops and open cars. The mesh must cover the driver compartment and passenger compartment unless the car is driven solo.
E. Materials, Fabrication, Bracing and Installation specifications are the same as the specifications for a Roll Bar. See Section IX for detailed information.
4. Specification: See Roll Bar Specifications for the roll cage fabrication specifications.
5. Main Hoop and Braces: The main hoop and support braces should be of the same size.
6. Minimum Tubing Sizing: The size of the tubing to be used shall be determined on the basis of the weight and speed potential of the car.
Vehicle Weight |
Tubing Material |
Tubing Dimensions |
| Under 2700 lbs. | Mild Steel | 1.50" O.D. X .120 wall |
| Alloy Steel | 1.50" O.D. X .090 wall | |
| 2700 to 3000 lbs. | Mild Steel | 1.75" O.D. X .120 wall |
| Alloy Steel | 1.50" O.D. X .120 wall | |
| Over 3000 lbs. | Mild Steel | 1.75" O.D. X .120 wall |
| Alloy Steel | 1.75" O.D. X .120 wall |
XI. RESTRAINT SYSTEMS:
1. Seat Belt Requirements:
B. All Other Divisions: A five (5) or six (6) point harness system is mandatory.
2) Mounting points must be at, or on the roll cage, frame member or body panel.
3) The belts should be mounted in such a way so as not to cause undue spinal compression and never above horizontal.
4) If mounted to the body panel adequate spreader plates should be used.
5) Belts must be mounted on a frame member or roll cage in the Unlimited Division.
6) Mounting to sheet metal (or fiberglass) is specifically prohibited.
2. Belt/Restraint Age Requirements:
B. The belts must not be more than 24 months old in the Super Sport and Unlimited Divisions.
C. No belt/restraint showing wear and tear of any kind will be approved for competition.
3. Arm Restraints: Arm restraints are mandatory in Unlimited and highly recommended in all other Divisions.
4. Seats: Seats must be firmly affixed to the roll cage and/or basic structure of the car. The use of proper racing seats is recommended. Aluminum, steel or fiberglass material is recommended.
5. Engine/Transmission Restraints: For the Unlimited Division the following is mandatory and recommended for the Super Sport Division.
B. Solid mounts are recommended.
C. Intrusion of the engine/transmission into the cockpit compartment must be prevented by the means of solid mounts or restraints, (i.e., chains), or bars attached to the roll cage.
6. Recommendations:
B. The use of helmet restraints are recommended.
C. Sternum belts are recommended for seats which do not support the shoulder straps. However, large metal buckles on the sternum strap are not recommended.