Jasongray5
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| posted on 14/1/09 at 04:29 PM |
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Roll hoop metal thickness question
What thickness of metal should I use to make my roll hoop for a Haynes Roadster? Im going bike engined so it will be lighter than the prototype?
Many Thanks Jas Gray
How hard can it be?
http://www.flickr.com/photos/33261515@N03/sets/72157611049241239/
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Chippy
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| posted on 14/1/09 at 04:39 PM |
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Weight of car has little to do with the roll bar, stick with the recommended size in the book, which I think is 50mm dia x 3mm thick CRS. It's
there for your safety, so heavy is good. Cheers Ray 
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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Jasongray5
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| posted on 14/1/09 at 05:00 PM |
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Im not too worried about how much it weighs, obviously its safety first.!
How hard can it be?
http://www.flickr.com/photos/33261515@N03/sets/72157611049241239/
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mark chandler
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| posted on 14/1/09 at 05:28 PM |
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You will find bending CDS challenging, I had mine bent proffesionally to my own design after kinking a couple of bits.
ERW is easier and cheaper, if you want MSA spec then CDS is the chap to go for based upon the MSA blue book regulation sizes.
Quite often on Ebay sellers do flat pack ERW hoops and stays.
Regards Mark
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BenB
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| posted on 14/1/09 at 05:44 PM |
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quote:
Originally posted by Chippy
Weight of car has little to do with the roll bar, stick with the recommended size in the book, which I think is 50mm dia x 3mm thick CRS. It's
there for your safety, so heavy is good. Cheers Ray
Did anyone read last months Classics Monthly with the MG A racer with an aliminium tube roll bar??? Rather him than me!! Just to make sure it was naff
all use it also had lots of lovely holes drilled into it!!!!!! Perforated ali roll bar  It sure was shiny though!!! Doh!!!
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Bigheppy
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| posted on 14/1/09 at 06:36 PM |
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Some time ago a clan crusader (if memory is working) passed all inspections to go rallying, its rollover protection was made of fiberglass.
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jabs
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| posted on 14/1/09 at 09:36 PM |
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Robin Hood aka great british spots cars hoops are made from 50 x 1.5mm stainless
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BenB
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| posted on 14/1/09 at 09:51 PM |
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SVA inspector told me the roll cage for the RH Lightweight was made from finest exhaust tubing (accourding to the bloke that made the chassis)
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procomp
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| posted on 15/1/09 at 08:17 AM |
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Hi
If doing the job you may as well do it properly.
In which case use the Min spec for MSA 45mm x 2.5mm or 50mm x 2mm material CDS min yield strength 350 N/mm2 . The desighn would also have to
incorporate two rear stays for support. And technically the main hoop will want to be 50mm above your head when wearing a helmet so say 65mm above
without one.
At least when the trackday organisers are in future asking for MSA spec roll bars you will OK if you ever fancy doing a trackday.
Cheers Matt
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