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Building Roll Cage

Discussion in 'General Tech and Maintenance' started by brian1, May 4, 2004.

  1. brian1

    brian1 Junior Member

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    I plan to take this on for myself. Alright here's my question(s) what size pipe/tubing should be used when making a roll cage? I was considering 1.5" tubing. Mind you its only going to bea 6 point cage. Connecting at the rear shock towers, front up by the "Dead" pedal and lastly behind the seats. I've made measurements of hte main hoop being 114.5" long, the main hoop-to-shock towers being somewhere around 28", the main hoop to "dead" pedals being 58" and finally the cross bar being 52 7/8". This is for a CRX. If someone could give me measurements of an existing roll cage for my 90 CRX, just as a reference I would greatly appreciate it.
     
  2. pissedoffsol

    pissedoffsol RETIRED

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    what kind of racing do you plan to do? there's a rule book 23123 pages thick on roll cage requirements and design
     
  3. brian11to1

    brian11to1 Senior Member

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    Thanks B got my password fixed...



    I just want it to get rid fo the annoying seat belts ion the doors and to stiffen the body. Mainly AutoX
     
  4. E_SolSi

    E_SolSi Member of the 20 nut club Moderator VIP

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    get an SCCA rulebook and see what the requirements are
     
  5. brian11to1

    brian11to1 Senior Member

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    So no one can tell me the size to use without me getting the book? Ok, thanks.
     
  6. hybrid89

    hybrid89 thistownsucks...

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    i think most sactioned bodiess require 1.75" or larger, but I might be wrong.
     
  7. brian11to1

    brian11to1 Senior Member

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    About how much will 28' (feet) of that cost me?
     
  8. reckedracing

    reckedracing TTIWWOP VIP

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    i believe most cages are built with 1 and 5/8's with a thickness between .06 and .09 but i have no idea on the rules...

    what type of pipe do you plan to use and how do you plan to bend it?
    i am in the process of doing a roll cage as well... i tried 2" exhaust tubing to try and get a rough fit but my bender kinked the shit out of the tubing on anything more than a 30 degree bend or so maybe a 45...
    my next step would be some inch and 5/8's steel tubing, but just need to get time to go to the place to get it...

    search for honda roll cages on google to get the exact type of tubing they use...
     
  9. hybrid89

    hybrid89 thistownsucks...

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    that's why my car is going on a trailer on Sat and going to a shop to get the chromoly cage built. Most good fab guys know how to setup a cage. Also , go download the rule book for any sactioned racing clubs you might participate in.

    matt
     
  10. Sed8ed

    Sed8ed New Member

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    I usually use 1 1/2" ID electrical conduit (1 3/4' OD)... rigid or emt depending on the application (i've built 3 cages/bars to date). You will need to use a mandrel bender to make the bends and you can rent those from an electrical wholesaler for about $40 per day (ask for a hydrolic conduit bender). If you are looking to add rigidity to the chasis, I suggest going with an 8-10 point cage made out of emt conduit (thiner and lighter)... 2 mounts on the floor behind the front seats, 2 mounts on the factory cross brace (just use their bolt holes) 2 mounts by the rear shock towers and the 2 seatbelt mounts for the driver and passenger = 8... for 10 points add 2 forward support bars mounted to the main hoop at 18" from the floor and attaching to the floorboards just foreward of the front seats

    I've generally just used a modified version of the autopower roll bars but changing/adding mounting points as I see fit... make sure you weld around the joints completely and add a harness bar since you will probably end up loosing use of your stock seatbelts... the headrest restraint is also useful on a regular safety cage but not necessary on a reinforcement cage... diagonal bars are a plus

    do a google search for "honda roll bars" for design ideas and if it is a bolt in cage, make sure to put a plate under the car to sandwitch the body since the body material is so thin...

    autopower: http://www.autopowerindustries.com/Roll_Bars.htm

    cost:
    1 1/2 inch emt conduit : $1 per foot sold in 10 foot sections
    4 inch widesheet metal : $ Free from a sheet metal shop (in the scrap
    bins... use for mounting plates)
    conduit bender : $40
    wire and gas for welder : free from work but probably around $25
    LOTS of time

    Note: in order to get the bends correct for the main hoop, buy a section of cheap flexable copper pipe and bend that first into the shape you want for one side of the car, then copy it for the other side and you have a semetrical (sp?) main hoop that properly fits the contours of you car

    have fun :)
     
  11. asmallsol

    asmallsol Super Moderator

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    All open cars should have a roll bar installed to protect the occupant(s) from injury
    during a roll-over. The roll bar should be able to withstand the compressional forces
    involved in supporting the full weight of the car. The roll bar’s main hoop should extend
    the full width of the car (except certain cars that have been approved by NASA). The
    main hoop shall be one continuous piece with smooth bends and no evidence of
    crimping or wall failure shall be present (i.e. should be Mandrel bends). All welds shall
    be of the highest possible quality, with full penetration [Ref:(15.5.15)]. All mounting and
    installation procedures should conform to those standards listed in the CCR section #0
    regarding roll cages. ALL CARS with roll bars are required to have adequate roll bar
    padding per CCR section #15.5.4 and also conform to section #15.5.22 pertaining to
    seat back braces. The material and minimums are as follows: (All cars with full roll
    cages shall conform to the applicable sections found in section #15.0.)
    Vehicle weight Mild steel Alloy steel
    Under 1500 lbs. 1.50" x .120" 1.375" x .095"
    1501 - 2500 lbs. 1.75" x .120" 1.625" x .095"
    Over 2500 lbs. 2.25" x .120" 2.000" x .095"

    60
    15.5.1 Purpose
    The basic purpose of the roll cage is to protect the occupant in case of a rollover or a
    collision. It must be able to withstand the weight of the car landing on the roof. These
    rules apply to all classes, unless otherwise superseded by the class rules. Cars
    homologated by, or built to the specifications of, SCCA, IMSA, and Grand AM must
    conform to these rules, or may conform to their respective current class rules for roll
    cage requirements. It is the responsibility of the driver to have these (non-NASA) rules
    in his/her possession.
    15.5.2 Intent
    Chassis stiffening is a side benefit of a good roll cage system, but it is not the intent of
    these rules. Parts of the cage deemed by the Chief Scrutineer, to serve no practical
    purpose other than chassis stiffening may be considered in violation of the intent of
    these rules (Note: Some class rules allow for chassis stiffening.). The Chief Scrutineer
    may order the removal of said parts, or require that the vehicle owner redesign,
    reconstruct, and re-certify the roll cage if warranted. The removal or redesign of the
    cage, whole or in part, to comply with these rules, does not imply that penalties will not
    be issued for violating the intent of these rules.
    15.5.3 Installation
    The cage may be removable or may be permanently welded, or any combination
    thereof, providing that all aspects of the cage meet these rules.
    15.5.4 Padding
    All roll cage surfaces that may come in contact with the driver shall be padded with
    high-density padding such as Ethafoam or Ensolite. It is recommended that padding
    meeting SFI specification 45.1 be used.
    15.5.5 Bends
    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.
    15.5.6 Main Hoop
    The main roll cage hoop shall be as wide as the full width of the interior and must be as
    close to the roof as possible without violating CCR section #15.5.2 Inspection. One
    continuous length of roll bar tubing shall be used as the main hoop. The main hoop
    must consist of not more than four (4) bends maximum, totaling one hundred eighty
    (180) degrees +/- ten (10) degrees.
    15.5.7 Diagonal Brace
    At least one (1) diagonal brace shall be used in the same plane as the main hoop. One
    end of the diagonal brace shall attach to the corner, or horizontal part, of the main hoop
    above the driver’s head, within twelve (12) inches of the driver’s-side corner. The other
    end of the diagonal brace shall attach to the mounting plate (or to the main hoop as
    61
    close to the mounting plate as practically possible) diagonally opposed to the driver’s
    head (passenger floor).
    15.5.8 Forward Hoops (Option 1)
    The forward hoops shall extend from the main hoop (in a forward direction) to the floor
    by following the roof and the “A†pillar of the car. There shall be a bar connecting the
    two (2) forward hoops at the top of the windshield mounted as close to the roof as
    possible without violating CCR Section #15.5.20 Inspection. The forward hoops shall
    incorporate no more than four bends each. Optionally a “15.5.9 Halo Hoop (Option 2)â€
    or “15.5.10 Front Hoop (Option 3)†construction may also be acceptable.
    15.5.9 Halo Hoop (Option 2)
    A “halo bar†extends from the main hoop (in a forward direction) following the roof line
    to the windshield then following along the top of the windshield, then following the roof
    line back to the main hoop, thus creating a “halo†over the driver’s head. A “halo†bar
    shall be constructed of one continuous piece of tubing. One (1) down tube following
    the “A†pillar must support the “halo†on each side of the car. The down tubes shall
    incorporate no more than two (2) bends each.
    15.5.10 Front Hoop (Option 3)
    A “front hoop†is a bar that extends up from the floor, then follows the “A†pillar up to the
    roof, then follows the roof line across the top of the windshield, then back down the
    other “A†pillar, and then terminates on the floor. There must be one (1) horizontal bar
    (following the roof line) connecting the main hoop and the forward hoop on each side of
    the car. The front hoop shall incorporate no more than four (4) bends.
    15.5.11 Rear Braces
    The main hoop must have two (2) braces extending to the rear. The braces shall be
    attached as near as possible to the top of the main hoop, and no more than six (6)
    inches below the top. The braces must not contain any bends. There must be at
    least 30 degrees between the plane of the main hoop and the plane of the rear braces.
    The main hoop rear braces shall be installed to form no more than a one hundred five
    (105) degree angle or no less than a seventy (75) degree angle with the main hoop
    when viewed from the top. The main hoop braces may be mounted at the rear shock
    mounts or suspension pickup points (providing that the braces remain in compliance
    with all other sections of the CCR). They may go through any rear bulkheads provided
    the bulkhead is sealed around the cage braces.
    15.5.11.A Rear Braces - Exceptions
    On cars where the rear window/bulkhead prohibits the installation of rear braces
    (Porsche 914, Pontiac Fiero, etc.) the main hoop must be attached to the body by
    plates welded to the cage and bolted to the stock shoulder harness mounting location.
    There must also be a diagonal bar connecting the top of the main hoop to the lower
    front passenger side mounting point (“Petty barâ€). Some cars built for racing in other
    recognized sanctioning bodies may be granted a waiver of this rule, however they must
    show proof of compliance with the current published rules for their class.
    15.5.12 Door Bars / Side Impact Protection
    At least one (1) door bar on driver side and one (1) on the passenger side must be
    used. The driver’s door window glass, window operating mechanism, armrest, map
    pockets, door panel, and inside door latch may be removed providing that is for the
    62
    sole purpose of installing “NASCAR†style door bars.* The stock side impact beam, if
    equipped, and the outside door latch/lock mechanism shall not be removed or modified.
    *This gutting of the door is only permitted on driver’s door and, if undertaken, the roll
    cage must incorporate at least two (2) NASCAR style door bars that extend into the
    door. Certain class rules may supersede this rule. “NASCAR Style†means to
    NASCAR specification in regard to configuration. For example, the two required bars
    should be parallel with respect to each other, and contain the appropriate vertical
    support tubes. See NASCAR rules for more information.
    15.5.13 Mounting Points
    The roll cage shall be mounted to the floor of the car in six, seven, or eight points. The
    cage shall not go through the firewall. The seventh and eighth points must attach to
    the firewall or front fender wells. All cage attachment points must be mounted to
    plates. Each required cage bar shall terminate on a plate with a 360 degree weld to the
    mounting plate, except as specified in Section 15.5.14.B. There shall be only one (1)
    mounting “point†per plate. This point is defined as where the “required tube†mounts.
    All additional tubes mounted to that plate must be mounted as close to the required
    tube as possible [Ref: (15.5.14.B)].
    15.5.14 Mounting Plates
    Each mounting plate shall be no greater than 100 square inches and no greater than
    12 inches or less than 2 inches on a side. Welded mounting plates shall be at least
    0.080-inch thick. Plates may extend onto vertical sections of the structure. Any
    mounting plate may be multi-angled, but shall not exceed 100 square inches total
    including vertical sections. Each mounting plate should have an area of not less than
    nine (9) square inches.
    15.5.14.A Mounting Plates – Bolt-In Cage
    The attaching points of a bolt-in cage to the body must use reinforcing plates to
    sandwich the body. At least three (3) bolts are required for each bolt-in plate and the
    plate must be at least 3/16 inch thick. All hardware must be SAE Grade 5 or better with
    5/16†diameter minimum. All nuts must be held securely by a locking system such as
    safety wire, lock washer, Ny-lox, or jam-nuts.
    15.5.14.B Tube / Mounting Plate Specifications
    Any number of tubes may attach to a plate so long as they are touching each other at
    the plate. There may be a small gap between tubes to allow welding 360 degrees
    around each tube. If there is no gap between the tubes, they must be welded around
    the base as much as possible to form a single figure-eight weld, AND the tubes must
    be welded to each other two (2) inches up from the base plate.
    15.5.15 Welds
    All welding must be of the highest quality with full penetration and shall conform to the
    American Welding Society D1.1, 1994 Edition, Structural Welding Code, Chapter 10,
    Tubular Structures and Standards for the material used. Arc welding should be used
    whenever possible. It is strongly recommended that the welder inspect all welds using
    Magnafluxâ„¢, x-ray, or other effective methods. All tubes must be welded 360-
    degrees around the circumference of the tube.
    15.5.16 Tube Structure Design / Body
    63
    Tubes may touch the body in any place (not to violate CCR section #15.5.2 Inspection),
    but shall not be attached anywhere except as permitted by CCR Section #15.5.11.A
    Rear Braces - Exceptions. No deformation of the interior body panels is permitted,
    except that the horizontal part of the sheet metal between the main hoop and the top of
    the “A†pillar (next to the driver’s and/or passenger’s head), may be pushed in to
    accommodate the roll cage. The intent of this allowed deformation is strictly to allow for
    more headroom for the driver and/or passenger.
    15.5.17 Additional Reinforcement
    Any number of additional reinforcing bars are permitted within the structure of the cage
    provided that they are installed strictly for safety and do not violate CCR Section
    #15.5.2 Intent. This rule does not permit reinforcements in classes with spec cages.
    All required bars must be made of the same material and meet with at least the
    minimum specifications for size and thickness.
    15.5.18 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 1500 lbs.
    1.375†x 0.095†DOM/Alloy/Seamless
    1501 - 2200 lbs.
    1.500†x 0.095†DOM/Alloy/Seamless
    (No issuance of log books for cars with ERW cages being certified after April 30th,
    2003)
    2201 - 3000 lbs.
    1.500†x 0.120†DOM/Alloy/Seamless
    1.750†x 0.095†DOM/Alloy/Seamless
    (No issuance of log books for cars with ERW cages being certified after April 30th,
    2003)
    3001 - 4000 lbs.
    1.750†x .120†DOM/Alloy/Seamless.
    No ERW allowed.
    Over 4000 lbs.
    2.000†x 0.120†DOM/Alloy/Seamless.
    No ERW allowed.
    15.5.19 Bending Allowances
    If the maximum number of bends is exceeded all components shall be made from the
    tubing size listed for the next heavier category and must be approved by a NASA race
    tech station or scrutineer.
    15.5.20 Inspection
    A 3/16-inch inspection hole must be drilled in each of the required bars in a non-critical
    area for the purpose of determining wall thickness. All welds, except those mounted to
    plates on the floor, must be accessible for inspection (360 degrees).
    15.5.21 Head Restraint
    A head restraint must be used to help prevent whiplash. The head restraint shall have
    a minimum area of thirty-six (36) square inches and be padded with a non-resilient
    material such as Ethafoam or Ensolite with a minimum thickness of one (1) inch. It is
    recommended that padding meeting SFI specification 45.1 be used.
    15.5.22 Seat Back Support
    A seatback support must be made to hold the seat from going back in the event of a
    crash. A plate should be used to distribute the load. No bolts, corners, or sharp
    objects should be placed is such a manner that could lead to a possible puncture of the
    driver in a high impact crash. Proper design and installation is crucial to safety and it is
    recommend that the driver employ the services of a professional race car builder for
    this, as well as all other vehicle safety items. An exception may be made for those
    seats homologated to, and mounted in accordance, with FIA 8855-1999 standards.
    Those seats that qualify for the aforementioned exception must conform to the entire
    FIA 8855-1999 set of regulations. This includes a mandatory seat replacement of any
    seat more than five (5) years old. Please reference the FIA regulations.
    http://www.fia.com
     
  12. nfn15037

    nfn15037 Senior Member

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    Is this some kind of joke? Electrical conduit is made to shield and protect WIRE not to hold a car roof up when it is upside down! Please, use some good stuff for cages, at the very least ERW(with the appropriate wall thickness) steel and at the higher end some Cro-Moly. Please say this was some joke :( Id love to see how a harness bar made out of conduit holds up in a frontal impact :unsure:
     
  13. asmallsol

    asmallsol Super Moderator

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    defently something that you dont want in a roll bar.
     
  14. brian11to1

    brian11to1 Senior Member

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    STOP REPLYIN TO THIS POST. IM JUST GOING TO HAVE A SHOP NEAR ME MAKE A DAMN CAGE.
     
  15. B16

    B16 Super Moderator VIP

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    pull your panties out of your crotch


    and Sed8ed i reeeealy hope you were joking with that post...
     
  16. brian11to1

    brian11to1 Senior Member

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    There's no reason to keep the thread going once I've completely changed my mind, now is there?
     
  17. B16

    B16 Super Moderator VIP

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    well, hate to break it to you, but you are not the only one who reads these threads.
    now that we have that settled, i would rather have things cleared up as to what types of materials can and cannot be used. this way when someone happens to search and find this thread, they don't think "oh wow, i could just use some conduit and build a cage!".

    get it??
     
  18. Sed8ed

    Sed8ed New Member

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    Sorry, I should have explained myself more clearly... I wrote that too late at night. Firstly, I would not use regular couduit for a STRUCTURAL cage in the first place (at least not EMT) rather for a chasis stiffening aid. Secondly, the copper pipe is only used to get the measurements for the main hoop to later be copied onto the proper material.

    Rigid conduit is a different all together, it is mild steel with a wall thickness of .139 inches, the requirement is .120 inches.

    If you re-read my post, I did not say to use regular conduit for a safety cage rather I suggested against it. The two cages I have built have been for sanctioned autocross events and they were built strictly to stiffen the chasis...NOT to protect in a frontal impact or rollover... both passed inspection because they were not made to protect the driver rather to aid in vehicle control (and yes they were drilled)...

    My mistake, I thought this was the purpose of this post
     
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