Found the below info posted on another forum & posted them in response to a question. I got to thinking that they will be hard to find in that thread. Since SCORE no longer makes their rules available on-line perhaps they should be posted to the COG under their own title? Mods, if this qualifies, feel free to move it to COG. VEHICLE SAFETY EQUIPMENT CR33 ROLL CAGES All vehicles in competition except Motorcycles and ATV’s must be equipped with a roll cage. Minimum design and tubing size based on seamless 4130 chromoly tubing or ASTM 1018/1026 CDS/DOM. No aluminum or other non-ferrous material permitted. Material Material for roll cage construction must be 4130 chromoly tubing or ASTM 1018/1026 CDS/DOM. All welding must be of the highest quality with full penetration and no undercutting of the parent metal. All welds shall conform to the American Welding Society D1.1, Structural Welding Code, Chapter 10, Tubular Structures and Standards for the material used (see AWS. Org). It is strongly recommended that the welder inspect all welds using Magnaflux™, die-penitent, or other effective methods. All tubes must be welded 360-degrees around the circumference of the tube. No oxy-acetylene brazing or welding allowed. Good external appearance of a weld does not necessarily guarantee its quality, poor looking welds are never a sign of good workmanship. None of the tubing may show any signs of crimping or wall failure. All bends must be mandrel type. The center radius of the bends may not be less than three (3) times the outside diameter of the roll cage tubing. It must be emphasized that the use of heat-treated or high carbon steels may cause problems and that bad fabrication may result in a decrease in strength (caused by brittle heat-affected zones), inadequate ductility and internal stress. Roll Cage Tubing Sizes For the purposes of determining roll bar tubing sizes, vehicle weight is as raced, but without fuel and driver. Note: There is an allowance of minus 0.010 inches on all tubing thicknesses. Minimum tubing size for the roll cage is: Up to 2000 lbs. 1.500” x 0.095” CDN/4130/Seamless or ASTM 1018/1026 CDS/DOM 2001 - 2500 lbs. 1.500” x 0.120” CDN/4130/Seamless or ASTM 1018/1026 CDS/DOM 2501 - 3000 lbs. 1.750” x 0.095” CDN/4130/Seamless or ASTM 1018/1026 CDS/DOM 3001 - 4000 lbs. 1.750” x .120” CDN/4130/Seamless or ASTM 1018/1026 CDS/DOM Over 4000 lbs. 2.000” x 0.120” CDN/4130/Seamless or ASTM 1018/1026 CDS/DOM Construction Procedures Cages must be securely mounted to the frame or body and gussetted and braced at all points of intersection. Cab or body mounted cages must not be attached to the body structure by direct welding, but must be bolted through and attached by the use of doubler plates (one on either side) with a minimum thickness of .187”, see Figure 4. Where bolt and nuts are used the bolts shall be at least .375” diameter SAE Grade 8 or equivalent. Roll cage terminal ends must be located to a frame or body structure that will support maximum impact and not shear. Minimum material dimension requirements for roll cages apply to the following members of the roll cage: (1) Front and rear hoop (2) Front and rear interconnecting bars (3) Rear down braces (4) Lateral bracing (5) Elbow and door bars (6) Lower A-pillar tubes, and lower B-pillar tubes Roll Cage Design All roll cages must be constructed with at least one (1) front hoop (top of cage to floor), one (1) rear hoop(top of cage to floor), two (2) interconnecting top bars, two (2) rear down braces and one (1) diagonal brace and necessary gussets, see Figure 1. If front and/or rear hoop terminate at elbow/door bar, lower A-pillar and/or B-pillar must be made of same tubing size as roll cage. Centerlines of all required tubes must converge at intersections. Any vehicle that is not provided with stock steel doors for its driver and co-driver must be equipped with sidebars, at least one on each side that will protect the occupants from the side. These bars must be parallel to the ground (or as close to parallel as is practical) and be located vertically in relation to the occupants to provide maximum protection without causing undue difficulty in entering or exiting the vehicle. The sidebars must be formed of tubing of the same material and dimensions as the roll cage itself and must be securely attached to the cage’s front and rear members. Additional side tubes may be required to limit cockpit intrusion, these additional tubes must be of the same size tubing as the roll cage. Tubes must be placed in such a manner as to limit openings adjacent to the occupants. Maximum opening size in this area is limited to 370 square inches. All roll cage bars must be at least 3” in any direction from the driver and co-driver’s helmets while they are in their normal driving positions. Gussets must be installed at all main intersections on the main cage including diagonal and rear down braces, and where single weld fractures can affect driver’s safety. Gussets may be constructed of .125” X 3” X 3” flat plate, split, formed and welded corner tubing, or tubing gussets the same thickness as the main cage material, see Figure 2 and Figure 3. Rear down braces and diagonal braces must angle no less than 30 degrees from vertical. An inspection hole of at least .187” diameter must be drilled in a non-critical area of the roll bar hoop to facilitate verification of wall thickness. It is the prerogative of SCORE to drill a second hole if deemed necessary. Any cage or chassis that has been built after January 1, 2006 must be identified by means of an identification plate affixed to it by the manufacturer; this identification plate must be neither copied nor moved (i.e. embedded, engraved or self destroying sticker). The identification plate must bear the name of the manufacturer, a serial number, and the date of manufacturer. Head/neck restraints designed to prevent whiplash are required on all vehicles. These restraints must be a headrest of approximately 36 square inches, with a resilient padding at least 2” thick. Any portion of the roll bar or bracing which might come in contact with the helmet must be padded.