dhutch
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| posted on 15/11/08 at 10:35 PM |
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Roll Hoops?
I thought i would post here becuase it might get a more engineered response than on WSCC where money seams typically less restricted!
I have a 17yo narrowboat feild which currently has the standard 'road hoop' which seams to be designed to look good and hold three point
recoil seatbelts.
However im planning to take the car to trackdays, and im 6ft2. So having my head four inchs above a rollbar made of cheese doesnt feel to great.
My plan is to fit a decent, rac-style braced rollbar. As a compromise between no protection, and a full cage.
- Geting quotes from Caged and Procomp comes out with prices of £350(+vat) for a bolt-on kit from caged, or £450(+vat) fitted by ProComp (weld in
being there preference).
They dont seam bad prices, but for a student, on a sub four grand car, its not free either.
So i also have a quote of £170 for a 'kit of parts' from Fabicage.
- Ie, they will bend a bar to my dimentions, and include two bars with profiles ends and fittings for the rear stays.
- So i have to mate it all to the car, then weld (or have someone weld) the rear stays and some mounting plates on.
I dont really feel my welding is upto spec to do the job myself, and its not something i really want to skim on, or use the wrong tube on. Im
proberbly not going to do any compeating in the car, but i might do some sprints, so would be tempted to go fo 1" 3/4 bar to comply with
MSA/FIA or whatever?
Alternatively, does anyone else know where i might get any other quotes from. Or any other thoughts or considerations.
Proberbly looking at a bar about 500mm tall.
Daniel
Daniel
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big_wasa
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| posted on 15/11/08 at 10:44 PM |
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If you tack it in place I am sure you would get some one to weld it up for beer money. Then again if procomp does it its done once and done well.
The hard work is in getting it all to fit with out gaps between the tubes.
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RichardK
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| posted on 15/11/08 at 10:49 PM |
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I got mine in kit form and did the fishmouths etc and welded it up, I got it from MNR in Harrogate and think it was about £100 if I remember
correctly.
I'm 6'5" so wanted a bar that when I have my helmet on was still a couple of inches above my head, I measured from the top of the
cam shaft pulley upward and this dictated to me how high the roll bar was to be, some say it looks odd but I value my loaf before looks!
Hope this is of help.
Cheers
Rich
[Edited on 15/11/08 by RichardK]
Gallery updated 11/01/2011
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dhutch
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| posted on 15/11/08 at 10:54 PM |
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Yeah, sounds good for £100 from MNR.
- What gauge/dia tube did you go for? 12 gauge ERW tube?
The other way ive seen in done on westfeild roll over hoops is to use rose joints at both ends of the rear stays, giving some conformance for there
exact lenght/angle/position.
Like this
http://cgi.ebay.co.uk/WESTFIELD-LOCOST-OR-KIT-CAR-ROLL-OVER-BAR-OR-HOOP_W0QQitemZ190264459369QQcmdZViewItem?hash=item190264459369&_trksid=p3286.c0
.m14&_trkparms=72%3A1301%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318
Daniel
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RichardK
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| posted on 15/11/08 at 11:07 PM |
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38mm cds tubing
Cheers
Rich
Gallery updated 11/01/2011
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mark chandler
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| posted on 15/11/08 at 11:54 PM |
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I made mine from the correct CDS tube, this cost around £50 for a 5m length so I guess it would be lots more now. You will not bend this without the
correct kit so I made a dummy hoop out of scaffold then visited my local pipe bending outfit who charged £15 per bend, they then cloned my dummy
hoop.
So a MSA spec hoop and stays at £100 sounds maybe a bit cheap.
Rose joints do not meet MSA specs in this application.
Regards Mark
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dhutch
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| posted on 16/11/08 at 12:02 AM |
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quote:
Rose joints do not meet MSA specs in this application.
Right! So certainly no point in specing a 1 3/4 bar and then using rose joints then!
- I sure how much i liked the idea, but ive seen it enough to mention it, and as was pointed, at the end of the day the chassis is only inch box and
the rear stay mounts are just u brackets off that, unless i do somthing else.
How well considered is bolting the base of the hoop to the chassis.
- The orignal is, and with some suitable bolts (2-3 m8 high tensiles each side?) i would be as stong as anything else.
- I had thought if there rose joints or hole and pin joints at the top of the stay it would be taking the bar of fairly easy. But maybe thats not
important.
The next job is raising the roof of the trailer a little to fit all this in!!
Daniel
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big_wasa
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| posted on 16/11/08 at 09:10 AM |
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Again I did mine myself. I am 6'3" so wanted at least 50mm above an helmet.
[Edited on 16/11/08 by big_wasa]
 
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mark chandler
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| posted on 16/11/08 at 09:16 AM |
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Bolts on shear are amazingly strong, you can lift a double decker bus on a 1/2" bolt apparantly.
That aside yes the chassis is smaller tube than the cage but the regulations are generic to a large degree so the 2" hoop diameter is the same
for off roading cages which may hit a tree at 60mph so for this overkill. MSA approved cages by safety devices etc are smaller tube on caterhams but
these have been through a rigourous test procedure and have lots of diagonal bracing.
My hoop sits on the top of the rear bulkhead, same as above this is a pretty strong area with bracing and the rear stays go to the rear corners so
triangulate the chassis making the whole thing stronger.
It would be a very hard impact to collaspe the front into the drivers zone of the car or crush from above, the danger with a single hoop is landing on
a fence upside down or something coming in from the side.
Regards Mark
[Edited on 16/11/08 by mark chandler]
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dhutch
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| posted on 16/11/08 at 10:50 AM |
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Yeah, well my other question that i didnt ask anyone wile phoning round was about side bars (or one side bar) and also bolt-in petty bars. And how
they fair in terms of improvments to strenght and the like.
- Partiularly in the narrower cars you fee very side exposed! As you elbow is 4inchs outside of the car.
Common sence and general thought seams to suggest that 1 1/2 inch CDS is perfectly suitable to a seven, and can with the right bracing and testing,
pass MSA reg. Although for an untested/uncerted the minimum spec is 1 3/4 which would be fractionall heavier (1.16 times).
- Would a 1 3/4 bar with 1 1/2 inch rear and diagonal braces be ok? Does anyone have the publisiced rules as i can find anything about on the MSA
site.
Daniel
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mark chandler
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| posted on 16/11/08 at 10:53 PM |
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You need the MSA blue book for all the rules and regs, if you apply for a race licence you get one thrown in. Best to put up a new post to see if
anyone has an old one they do not want anymore.
Regards Mark
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procomp
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| posted on 17/11/08 at 08:11 AM |
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Hi.
I should point out that the quote by Procomp / Me. Was using correct MSA specification tubing and done to the criteria laid out in the BLUE BOOK. I
am in possession of the NEW 2008 onwards FIA / MSA regulations That both the scrutineers and rollbar / cage manufacturers should be working from.
However some manufacturers clearly have never read the regulations or seem to be ignoring them them.  I will U2U Re the FIA / MSA regulations
etc.
Also there is no vodka and tonic.
Cheers Matt
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:{THC}:YosamiteSam
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| posted on 18/11/08 at 11:49 AM |
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quote:
Originally posted by mark chandler
Rose joints do not meet MSA specs in this application.
Regards Mark
my caged westy full cage came with rose joints on the rear diagonals where it joins the fuel tank area - same as the msa spec roll bar westfield
supply that most people race with
they screw into the end of the bar into a chunky thread
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procomp
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| posted on 18/11/08 at 12:26 PM |
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Hi
Regardless of what they supply. The regulations changed some time ago regarding what is aceptable as a mounting point and it's connection /
joint.
Cheers Matt
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:{THC}:YosamiteSam
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| posted on 18/11/08 at 12:40 PM |
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quote:
Originally posted by procomp
Hi
Regardless of what they supply. The regulations changed some time ago regarding what is aceptable as a mounting point and it's connection /
joint.
Cheers Matt
wouldnt that depend on what the use is? circuit racing of course is a lot tighter - but if its sprinting or road use or track days its not required..
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procomp
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| posted on 18/11/08 at 02:29 PM |
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Hi
Obviously if you are talking road use only then you can do almost whatever you like. For sprinting and hill climb use in a road going class the
regulations are a bit more relaxed than racing. But if in any other class and running under MSA regulations then the roll cage must comply with FIA /
MSA regulations.
Cheers Matt
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