KaiPL
Enthusiast
I was looking at the roll bar specs for Silver State Classic and Sand Hill Challenge events, and comparing these specs to the Autoform bar.
The fore/aft bracing requirement looks like it might not be met, although perhaps the diagonal placement would offset that some.
Don't know about the mounting requirements.
Here are the Sand Hill/Silver State specs:
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.
A. The top of the roll bar shall not be below the top of the driver’s helmet in a closed car and a
minimum of two (2) inches above the driver’s helmet in an open car when the driver is in the
normal driving position. It shall not be more than six (6) inches behind the driver.
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 Event Director will be
final.
C. The two vertical members forming the side 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.
A. The size of the tubing to be used must be determined on the basis of the weight and speed
potential of the car.
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.
A. All welding must be of the highest quality with full ***********. Arc welding should be used
whenever possible. All attachments points must be welded 360 degrees around the tube.
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.
A. All roll bars must be braced in a for or aft direction with the brace attached within six (6) inches
of the top of the hoop, and at an angle of at least thirty (30) degrees from vertical.
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 driver’s side and attached to the
bottom on the “passenger” side.
C. A headrest is required if not part of the seat.
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. When the main hoop is attached to
sheet metal, such as a floor attaching point for unibody cars, the mount plate must be at least 36
square inches (6” x 6” plate) on both sides of the sheet-metal.
A. A minimum of double-nutted grade 5 bolts for self-locking or welded nuts shall be used to bolt
to the car. No bolts are needed if the bar is welded to the car’s frame.
B. In the case of cars with unitized or frame less construction, mounting plates must be used to
secure the roll bar structure to the floor of the car. The important considerations 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 Space Frame or Frame less 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 and single tube of the frame.
On cars of frame less construction, consideration should be given to using a vertical roll bar hoop
of 360 degrees completely around the inside of the car, and attaches 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.
Under 1500 lbs. ERW, CREW 1.50” O.D. X .120 wall
DOM 1.50” O.D. X .090 wall
1500 to 2700 lbs. ERW, CREW 1.75” O.D. X .120 wall
DOM 1.50” O.D. X .090 wall
2700 lbs & over ERW, CREW 1.75” O.D. X .120 wall
DOM 1.75” O.D. X .090 wall
The fore/aft bracing requirement looks like it might not be met, although perhaps the diagonal placement would offset that some.
Don't know about the mounting requirements.
Here are the Sand Hill/Silver State specs:
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.
A. The top of the roll bar shall not be below the top of the driver’s helmet in a closed car and a
minimum of two (2) inches above the driver’s helmet in an open car when the driver is in the
normal driving position. It shall not be more than six (6) inches behind the driver.
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 Event Director will be
final.
C. The two vertical members forming the side 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.
A. The size of the tubing to be used must be determined on the basis of the weight and speed
potential of the car.
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.
A. All welding must be of the highest quality with full ***********. Arc welding should be used
whenever possible. All attachments points must be welded 360 degrees around the tube.
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.
A. All roll bars must be braced in a for or aft direction with the brace attached within six (6) inches
of the top of the hoop, and at an angle of at least thirty (30) degrees from vertical.
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 driver’s side and attached to the
bottom on the “passenger” side.
C. A headrest is required if not part of the seat.
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. When the main hoop is attached to
sheet metal, such as a floor attaching point for unibody cars, the mount plate must be at least 36
square inches (6” x 6” plate) on both sides of the sheet-metal.
A. A minimum of double-nutted grade 5 bolts for self-locking or welded nuts shall be used to bolt
to the car. No bolts are needed if the bar is welded to the car’s frame.
B. In the case of cars with unitized or frame less construction, mounting plates must be used to
secure the roll bar structure to the floor of the car. The important considerations 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 Space Frame or Frame less 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 and single tube of the frame.
On cars of frame less construction, consideration should be given to using a vertical roll bar hoop
of 360 degrees completely around the inside of the car, and attaches 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.
Under 1500 lbs. ERW, CREW 1.50” O.D. X .120 wall
DOM 1.50” O.D. X .090 wall
1500 to 2700 lbs. ERW, CREW 1.75” O.D. X .120 wall
DOM 1.50” O.D. X .090 wall
2700 lbs & over ERW, CREW 1.75” O.D. X .120 wall
DOM 1.75” O.D. X .090 wall
