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Roll bar diameter
splitrivet - 26/1/04 at 01:12 PM

Bit of a stoopid question I know but what diameter tube have you guys used for a roll bar.

Reason is I scrounged some 1 3/4 inch dia 1/8 wall tube (they didnt have any 2 inch) just long enough to bend a roll bar out of,would this be meaty enough for a roll bar.
Not that Im planning on rolling the car you understand.
Cheers,
Bob


dozracing - 26/1/04 at 01:18 PM

Thats more than plenty. Thats heavier stuff thant he MSA motorsports body require for a race hoop.

Kind regards,

Darren


splitrivet - 26/1/04 at 01:20 PM

Thanks Darren
Bob


jonti - 26/1/04 at 09:53 PM

sindes a bit skinny fer meh yooth

marns abite tiw an a hafe ah think.

cosner find a birra dinespite ?

tha nehds a birra good stuff told it of thee yed when theet upside dine tha nowst !

Seriously ....our kids got an ex Toyota Hilux roll bar goin cheep in Tunstall if it'll mod.......dunno if it will but it might......if you're interested I'll have closer look for you.

[Edited on 26/1/04 by jonti]


type 907 - 27/1/04 at 12:08 AM

Hi

Just looked it up in the SVA book.

It says, "For guidance ideally should be made from CDS, 45mm x 2.5 wall or 50mm x 2mm wall. "

Hope this helps.

Paul G


craig1410 - 27/1/04 at 01:20 PM

Doz,
Are you sure about the MSA regs. I thought that the figures in type 907's posting were based on the MSA recommendations and thus 45mm x 2.5mm was the minimum CDS tubing allowed. 1.75" is marginally under 45mm (44.45mm I make it) and although common sense tells me that the extra 0.5mm wall thickness will make up for this, I don't know how rigidly the MSA would apply this rule.

Also, be aware that the amount of ovalisation must be controlled when bending the tubing for MSA rules. I think it has a limit of 90% minimum normal diameter at the narrowest part of the bend.

All this is for MSA though so if you want to run on the road just make sure that doesn't have any sharp edges. If you are planning to attach your seatbelts to it then you may want to make it MSA compliant and then hopefully this will more than please the SVA man. I believe backstays are required for seatbelt attachment but this is the topic of some debate...

My home made rollbar is just made from black pipe but it is 48mm diameter and 2.8mm thick. I did some sums at the time and even taking account of the difference in strength between black pipe and CDS this is roughly the same strength as a 50mm x 2mm piece of CDS. I'm not planning to race it so this is fine IMHO. I also added backstays made out of 16swg x 38mm tubing but these are more for cosmetic effect rather than strength and my seatbelts will attach to the chassis not the rollbar.

Cheers,
Craig.


jonti - 27/1/04 at 01:22 PM

Yep ..just checked and mine's 50mm

Checked the Toyo one and that's 75mm so ...might be a bit thick.


twentyover - 1/2/04 at 07:34 PM

Depends on the material. If ERW tubing, there are constraints about eher the seam should be placed. I seam (ok, poor play on words) to recall the weld line needs to be dead on the inside radius of the bends in the hoop. DOM or CDS have no apparent seam, so are relayively unconstrained


craig1410 - 1/2/04 at 07:45 PM

Twentyover,
I bent mine with the seam along the curve as I thought this would have less chance of tearing. To clarify, my seam is neither on the outside or inside of the bend, it is 90 degrees with respect to both. By the time it is prepared and painted it should be impossible to tell where the seam was anyway!

I guess your comments were motorsport related anyway as the rollbar isn't required for road use.

Cheers,
Craig.


splitrivet - 2/2/04 at 04:26 PM

Arses looks like I'll have to buy some tube then,bent it with the seam on the inside simply so I had a datum for the bend.
Mind you is a roll bar an SVA requirement or is it if ones fitted its gotta be x inches in diameter.

Dust now wot I mean Jonti ar wost wine anyroad.
Cheers,
Bob

By the way is that Toyota pick up up for sale, after one, gotta be much cheapness tho

[Edited on 2/2/04 by splitrivet]


craig1410 - 2/2/04 at 09:13 PM

Splitrivet,
Don't assume that I am correct, I was half expecting someone to jump in and say that I was talking nutsack (I bet they can't resist now...)

Can anyone confirm where the seam on ERW should be when you bend it?

Cheers,
Craig.


jonti - 3/2/04 at 02:23 PM

[Originally posted by splitrivet
Arses looks like I'll have to buy some tube then,bent it with the seam on the inside simply so I had a datum for the bend.
Mind you is a roll bar an SVA requirement or is it if ones fitted its gotta be x inches in diameter.

Dust now wot I mean Jonti ar wost wine anyroad.
Cheers,
Bob
By the way is that Toyota pick up up for sale, after one, gotta be much cheapness tho
[Edited on 2/2/04 by splitrivet]




---------------------------------------------
Don't think (in fact I'm pretty sure) its not required for SVA....

Only have Toyota Roll Bar mate....not the vehicle......Ring Jeremy Clarkson..he's got one I think, although it may need a bit of bodywork !!!!


Tha' twine were orrite. weh drunk eet anna nuther one an gorra bit wobbly ....its nehw good onna Sundee neht nehter !!!.....me yed were thumpin lark a stehm ammer inth moanin !

I'm sure these other chaps haven't the slightest clue what we're talking about
old boy.


David Jenkins - 3/2/04 at 02:52 PM

quote:
Originally posted by jonti
[
I'm sure these other chaps haven't the slightest clue what we're talking about
old boy.


I can assure you that we have not the slightest interest in this authentic frontier gibberish!

David


splitrivet - 3/2/04 at 04:51 PM

Ar oop ere wir a mons a mon an shape git nirvus.

Think I'll just leave it as is then, ah well I can hear you all say, if the car rolls and you become a paraplegic dont come running to us.
cheers,
Bob


jonti - 3/2/04 at 05:42 PM

I can assure you that we have not the slightest interest in this authentic frontier gibberish!

David





Frontier Gibberish ?!!!!!.... How dare you sir ?........I'll have you know this is authentic Potteries gibberish being gibbered by two accomplished exponents of the art..

.. bet thee cosna see...cost kick a bow agen a woa an yed it with thee ed till it bosts ?.............cost ?


Spyderman - 4/2/04 at 01:41 PM

Erm, I think the word is,

BOLLOX


200mph - 4/2/04 at 02:06 PM

Craig, the seam on my roll bar from luego is on the side, so i suppose depending on mounting it could be either the front or the back, not the insife or outside if you get me

Mark


jonti - 4/2/04 at 05:05 PM

quote:
Originally posted by Spyderman
Erm, I think the word is,

BOLLOX



Inarticliate peasant! ..........Dont you know you spell BOLLOX wiva K ?

Its ..........BOLLOWKS !!!......... dear boy

You going to come to Splitrivet's proposed North Staffs Gathering ?

[Edited on 4/2/04 by jonti]


craig1410 - 4/2/04 at 09:27 PM

Mark,
Yes that is the same with mine and in my case the seam is towards the back of the car. Hopefully this is the way it should be... I'm sure I read somewhere that it is the correct way to bend seamed tubing.

Cheers,
Craig.


Simon - 5/2/04 at 12:57 AM

Just thought I'd have a look at mine, to see where the seem is

Guess what. There ain't one.

Hope this helps

ATB

Simon


200mph - 5/2/04 at 09:43 AM

Well I wouldnt imagine luego would be ballsing up a thing like a roll bar?

Otherwise half my car might fall apart

Mark


twentyover - 26/2/04 at 09:49 PM

Craig-

Sorry for the long time from last post- been away from a computer.

First, I was commenting on ERW tubing based on SCCA GCR's (General Competition Rules) which pretty much dictate design of saftey equipment for amatur racing in the US.

It's been a couple years since I last looked, but IIRC the seam was to be located in the inside radius of the bend. But it's been a couple years.

You're correct, though, if this is a street application, there's no need to subscrivbe to competition rules. When I make roll bars, whether street or race, I always subscribe to SCCA rules, as you never know when you maight want to convert it to a racer, and nothing pains me more then cutting out an existing cage (I know, I've done it) to replace it with one that complies with requirements.