Roll cage installation guide - illustrated to help with MSA compliance

Discussion in 'Track Prep & Tech' started by A.N. Other, Jul 3, 2008.

  1. A.N. Other Banned after significant club disruption Dec 5th 2

    Joined:
    Oct 23, 2003
    Likes Received:
    395
    Here is some guidance on how to properly install roll cage feet.

    The main purpose of the thread is to help our track car members who are unlikely to refer to the MSA Blue Book whilst installing a cage in a car which will not be seen by MSA scrutineers, at least not in the short term.

    But it will also help those preparing a race car, and draws on my experience as an eligibility scrutineer whilst liaising with the MSA scrutineers in the Mk2 Golf Race Series in 2007.

    So if your car is "just" a track car... you may not actually know if you'll later wish to use it in competition. BUT you can add value to it so that if you race it, the cage is done, and if you sell it, it is a car with an MSA-legal cage install, which helps with the value.

    So hopefully this should be useful, and add value to your car.

    Firstly, this is a guide mainly for bought manufactured cages, and is not designed to cover weld in kits or home brew cages (though the footplate information should still be close to right).

    What it doesn't cover is cage design, material thicknesses etc - please refer to the MSA Blue Book [STRIKETHROUGH]2008, page 152-184[/STRIKETHROUGH] 2009, page 156 - 189 here if a full comprehensive read is required.

    The thing to remember all the time is that a cage must fundamentally support the roof. So imagine when a car is dropped upside-down, straight onto the ground, and where the force goes.

    => straight to the cage feet.

    This is the main thing that occupies MSA scrutineers' minds as they inspect cars for safety before race meetings, and this applies to all


    Where do cage installs go wrong?

    • People buy cages, FIA approved etc, some come with pre-formed "reinforcement plates" to weld to the bodyshell. The owner duly installs them whilst assuming all is well, and then finds a scrutineer breathing down his/her neck asking for more strengthening work to be carried out, despite the writing on the box saying everything was included.

      Do not rely on reinforcement plates supplied by cage manufacturers. Check the spec against this post before grabbing the MIG.

      Rightfully people often find the actual cage install is enough work, without having to modify the actual installation feet as they do it. Cue red faces at scrutineering, often after burning the midnight oil to be there in the first place.
    • Shoddy welding
    • eBay specials being acquired, made of non-current specification, sometimes minus door bars. Cue scaffold poles or other seamed tubes start getting used for door bars, instead of the required seamless tube
    • Worth a mention that alloy cages are long since outlawed, and scrutineers arm themselves with magnets when suspicious

    MSA definitions:

    • [​IMG]

      (ref: 2008 MSA Blue Book, page 152)

    So, the MSA blue book stipulates that all A and B-pillar cage "mounting feet" must have 120cm squared "reinforcement plates" (aka "spreader plates"), made of 3mm steel plate. That's squared - so that's 10.95cm x 10.95cm on a square plate, or another combination with a rectangular plate (with the same surface area) 10cm x 12 cm.

    So there's the bodyshell of the car, the 3mm steel "reinforcement plate", and then the "mounting feet" of the cage itself and the cage tube which is welded to those feet.

    So, three layers then - always - and this is where some track cars scrimp, and a main focus of this post.

    Trackcar cages without these footplates not only will never be allowed to compete where a cage is required, but could also be turned away from a sprint or hillclimb if a scrutineer didn't like the install, even if a cage isn't required in the sprint/hillclimb class. Such a cage isn't installed to do its job, and in my view a scrutineer would be negligent by allowing such a cage install to run at speed and risk injuring a driver.
     
  2. A.N. Other Banned after significant club disruption Dec 5th 2

    Joined:
    Oct 23, 2003
    Likes Received:
    395
    Let's get started then!


    • A and B pillar cage feet

      [​IMG]

      (ref: 2008 MSA Blue Book, page 154)

      ^^ note: A and B-pillar footplates must have three 8.8 tensile spec bolts as a minimum specification to secure the cage to the footplates. 10.9 or 12.1 tensile specification bolts exceed 8.8 and are therefore also MSA compliant.

      ^^ it says "welded to the bodyshell" or "welded direct to the reinforcement plate", and does not specify whether continuous seams are required. However, usually continuous seams are what people do, so go with that.

      "This does not apply to backstays" means the two tubes that go down to the rear turrets / rear wheel arches from the main hoop. See below for how to install these mounting feet (under backstays heading).


    Three main foot designs

    • Version 1

      (images are thumbnail clickable)
      [​IMG] [​IMG]

      (pics courtesy of jamesa2)

      ^^ This first design requires L-shaped 3mm (minimum) brackets on the sill edge, taking a choice from these fitment guides:

      (images are thumbnail clickable)
      [​IMG] [​IMG]

      I assume the 120cm squared area is measured overall with these, but welcome comments.

      In the red car pictured I assume the cage reinforcement plate has captive nuts welded to the back of the floor plate And ~10mm holes drilled in the sills to accomodate them, before the L-shaped reinforcement plate is seam welded to the sill.

      Andrew - pls confirm

    • Version 2

      Designed to sit above the floorpan like this:

      (image thumbnail clickable)
      [​IMG]

      (pic courtesy of Eliot Dunmore)

      This second design involves fitting brackets designed to attach in multiple places and to spread load. This is from a Mk2 Golf GTI Championship car.

      In essence, the bracket is acting as a bridge over a space, and needs to be fairly strong to cope with the potential forces.

      This is the MSA diagram and whilst it's not the same as the picture above, the key thing is the load spreading plate at the bottom which runs horizontally across the floor.

      (image thumbnail clickable)
      [​IMG]

      The easy balls up to make in this scenario is to have the lower edge of the reinforcement plate pointing directly at the floor, with no reinforcement plate running across the floor. This is dangerous, since the edge will simply chop through the tin floor on impact, and the car will be a scrutineers' target from day 1.

      In various Mk2 Golf GTI cars, the pesky [:p] scrutineers insisted on an end plate being added to further strengthen the box structure - this was done on many cars last year - despite it not being listed in the Blue Book. It is understandable what they were saying (ie that the footplate could crush) and understandable how much extra strength the end-plates add - but this was a serious bit of roll-cage headachery for the competitors.

      (image thumbnail clickable)
      [​IMG]
      (pic courtesy of Eliot Dunmore)

    • Version 3

      Direct fitting to the floorpan on 3mm plate:

      [​IMG]
      (pic courtesy of Dclarke)

      ^^ Shows a B-pillar nearside floor plate installed - cage foot is bolted direct to floor - attached to a reinforcement plate simply MIGed to the floor area.

      (images are thumbnail clickable)
      [​IMG] [​IMG] [​IMG]

      ^^ The first has the 3mm plate below the floor, the second has it above the floor (best, in my opinion), and the third diagram appears to have domed bolt heads and no sign of any bolts/studs. Anyway, the first two cover the options really.

      The third design involves fitting flat footplates on the floor.

      But IMO the addition of L-shaped brackets tagged up the sill is better, like this:

      (image thumbnail clickable)
      [​IMG]

      The floor is made of tin, and tagging a footplate to the side of the inner sill is only going to add strength to the install.

      Here's some actual pictures of an install with the plate below the floor:

      [​IMG] [​IMG]
      (pics courtesy of Dclarke)


    Backstays (tubes that go to rear arches or turrets)

    Less detail on this one and no pics to hand (yet), but the cage rear stays that go onto the wheel arch mount as follows:

    [​IMG]

    (2008 MSA Blue Book, page 154)

    (images are thumbnail clickable)
    [​IMG]

    [​IMG]

    (2008 MSA Blue Book, page 154)

    This is an oddball cage design scenario, the sort I've not seen and is unlikely to be an issue - only put here for completeness.

    (images are thumbnail clickable)
    [​IMG] [​IMG]

    Three bolt rear stay installed - info still needed as to why MSA diags show two bolts and these cages clearly have the third...

    (images thumbnail clickable)
    [​IMG] [​IMG]
    (pics courtesy of Dclarke and jamesa2)



    Welding quality

    [​IMG]

    (ref: 2008 MSA Blue Book, page 155)

    Roll cage padding

    [​IMG]
    (ref: 2008 MSA Blue Book, pages 155 & 158)

    Once a cage install is complete, don't disregard the more proximate metal tubes inside the car. Preferably put some roll cage padding on the door bar, the bar above the door aperture, the B-pillar if the seat is set reasonably far back (or the car is 4-door) and bars under the dash if fitted.


    Boring disclaimer

    Obviously due to the function of a roll cage, this advice is all given in good faith, written because the MSA Blue Book is not in most track car owners hands. It is designed to help, but all work etc is your responsibility.


    Please comment or criticise

    If you do see anything that conflicts with your understanding, basic safety etc, please post your views or experience, to help refine the thread (whilst keeping it on topic - weld in cage specifics, cage design etc aren't in the scope - and off topic posts will be moved to separate threads).

    Clearly it's taken a little time to write, but I am more than happy to have the post picked apart to ensure it is spot on, so please don't tread on egg shells - thanks.

    If this post is copied to other forums, be good and credit www.ClubGTI.com - thanks :)
     
  3. StuMc

    StuMc Moderator and Regional Host - Manchester Moderator

    Joined:
    Nov 12, 2004
    Likes Received:
    266
    Location:
    50? 20` 47 N - 06? 57` 57 E

    While I`m not going to be fitting a cage any time soon, this is the method I would prefer. IMO those `pesky` scrutineers are right about the `crushability` of a non end-plated set-up.

    My question, however, would be;

    Could a slot be allowed to gain spanner access to the nuts?

    I`m just thinking that I wouldn`t want to hack apart an endplate to remove the cage for upgrade/replacement due to damage.

    Something like this (crude pic, I know. [:$] )

    [​IMG]
     
  4. Andy947 Forum Addict

    Joined:
    Oct 22, 2003
    Likes Received:
    39
    Location:
    Scotland, Aberdeen
    Its all very well getting the designs right, but is there any weld testing required to guarantee the strength of the welds?? MPI etc??

    its all too easy to mig up something that really has little strength??
     
  5. A.N. Other Banned after significant club disruption Dec 5th 2

    Joined:
    Oct 23, 2003
    Likes Received:
    395
    Stu - good point about the captive nuts, and I'd be intersted in other's comments. I can't make a call on that.

    Andy - I'd agree, and it's not explored by the MSA, except for the extract I've included above.

    We can only leave people to make their own judgments on whether their welding skills are adequate, or whether a cage should be put into a fab shop. The main thing would be to arm the owner with the knowledge of what to ask for in that circumstance.
     
  6. Andy947 Forum Addict

    Joined:
    Oct 22, 2003
    Likes Received:
    39
    Location:
    Scotland, Aberdeen
    I find it quite amazing that they go to great length to describe and detail certain designs for the connection points, Cages need to be built to certain regulations on designs etc but there is no fndamental requirement for weld testing, which ultimately dictates how the cage will perform.
     
  7. A.N. Other Banned after significant club disruption Dec 5th 2

    Joined:
    Oct 23, 2003
    Likes Received:
    395
    Agree - but it's not the subject of this thread.

    I suspect, if you're in Aberdeen, that you could be a coded welder or know coded welders, but until the MSA stipulate coded welding in race cars, which would broadly involve regulating the motorsport industry (and it's way too hooky for that) then it is going to be what it is.
     
  8. A.N. Other Banned after significant club disruption Dec 5th 2

    Joined:
    Oct 23, 2003
    Likes Received:
    395
    I'll add something about door bars actually - will bump when done.
     
  9. jamesa Forum Junkie

    Joined:
    Nov 8, 2003
    Likes Received:
    301
    Location:
    Abz
    Does appear so Chris, just looked into one of the fixing holes. There is one that does not - it`s the lower bolt on the B pillar base mount, uses a 7/16" UNF to locate into the seatbelt reel mounting. Apart from this all bolts are ISO 8.8 M10`s.

    Cage was installed by a Motorsport company, they prepare and run various cars and were `authorised` installers ... not sure what that actually means wrt any welding qualification. However, they came well recommended by a respected VW dealer / competitor and were the fabricator for much of his uprated / bespoke components. The rear cage is a standard SD item whilst the front, including doorbars were fabricated in-house to suit the `through dash` install. To my eyes the welding is excellent, as good as I`ve seen in industry and had passed both MPI and Radiography.
     
  10. Dub20vt Forum Member

    Joined:
    Oct 22, 2003
    Likes Received:
    0
    Location:
    Somerset
    as to welding strength the OMP cage i had for my old mk2 came with a leaflet stating that the FIA approval was only guaranteed if the cage is fitted by an approved roll cage fitter/welder.

    but as chris has said the responsibility lies on the vehicle owner really and wether they wish to attempt it themselves or find a coded welder/fabricator to do it for them.
     
  11. fthaimike Forum Addict

    Joined:
    Oct 27, 2003
    Likes Received:
    12
    Can we have a post on how much thread you can & cannot get away all the way along the bolt please?
     
  12. gillm

    gillm ***** User

    Joined:
    Oct 22, 2003
    Likes Received:
    3
    Location:
    yeovil somerset
    opps forgot about this sorry mike

    you should measure what the thickness of what you are going threw inc washers and get a plain shanked bolt to suit with maybe a few threads within the washers . any more could cause wather to creep up the threads and rot the floor pan out and even chaff the floor .
     
  13. fthaimike Forum Addict

    Joined:
    Oct 27, 2003
    Likes Received:
    12
    thanks dude. just wanted it discussed in here as i haven't heard it myself though that doesn't mean anything :lol: ;) .

    Will have to go hunting for some different bolts.

    So for us dumb amatures would this be correct for me....
    plain shanked M8 8.8 or higher bolt , spring washer, washer, cage foot, 3mm plate, washer?, then nylock nut
     
    Last edited: Jul 7, 2008
  14. gillm

    gillm ***** User

    Joined:
    Oct 22, 2003
    Likes Received:
    3
    Location:
    yeovil somerset
    well not saying its correct but being a aircraft engineer thats the way i was bought up :)
     
  15. fthaimike Forum Addict

    Joined:
    Oct 27, 2003
    Likes Received:
    12
    cheers again mate, much appreciated.

    one more thing for people, if you were to decide to have weld in captive nuts under the plate would they have to be any different?
     
  16. jamesa Forum Junkie

    Joined:
    Nov 8, 2003
    Likes Received:
    301
    Location:
    Abz
    If I was bolting the feet to the floor I would put a 3mm plate on the underside; would also have the nuts on the inside... regs permitting.
     
  17. fthaimike Forum Addict

    Joined:
    Oct 27, 2003
    Likes Received:
    12
    It's not to the floor mate, the 3mm i have listed above is the box section that will have the nut inside it.
     
  18. James W

    James W Motorsport Moderator

    Joined:
    Nov 24, 2004
    Likes Received:
    136
    Location:
    Berkshire
    Is there a way of getting a copy of the blue book without paying 53 for the go racing pack?
     
  19. jamesa Forum Junkie

    Joined:
    Nov 8, 2003
    Likes Received:
    301
    Location:
    Abz
    Yep - not nylocs

    Fair enough ...
     
  20. fthaimike Forum Addict

    Joined:
    Oct 27, 2003
    Likes Received:
    12
    Can someone tell me the recommended/required/advised gap to be between the main hoop & the roof in my mk1?

    my cage is pressing hard against the roof at the moment... & i am thinking the only way i can get around it is to shorten the legs on the main hoop, also anyone ever had to do this?
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice