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Roll Bar Backstays
handyandy - 24/7/09 at 08:40 PM

Hi all,

I,m currently making my Roll Bar Backstays (well earlier today i mean ), i,ve just been looking on the thread about dashboard layout/pictures......

and noticed that the first photo also shows the back stays of the roll bar which are attached with rose joints,
so can i ask if this will be ok for the new IVA regs & is it a good idea to use rose joints?

as to me it would make things easier for the installation & also easier for removal in the future as hopefully i intend to fit a full roll cage system.

thanks in advance for your help.

cheers
andy

lotusmadandy - 24/7/09 at 08:47 PM

Great idea to use rose joints Andy.
MK and MNR use them on the wishbones
so why not on the roll bar.
I can't imagine them causing IVA problems.

Andy

handyandy - 24/7/09 at 08:54 PM

Thanks Andy,

i would imagine the rose joints would need to be quite substantial ones, what size would you/anyone recommend ?

cheers
andy

David Jenkins - 24/7/09 at 08:58 PM

Why use rose joints? What's wrong with 2 flat surfaces and a big nut and bolt?

Yes - you'd have to take some care to make sure that the two faces were parallel, but that's not too hard.

The benefit would be that a well-made bolted joint is unlikely to be questioned by the IVA inspector, while still giving you the ability to dismantle the roll bar in the future.

Just my 2p's worth!

David

handyandy - 24/7/09 at 09:10 PM

quote:
Originally posted by David Jenkins
Why use rose joints? What's wrong with 2 flat surfaces and a big nut and bolt?

Yes - you'd have to take some care to make sure that the two faces were parallel, but that's not too hard.

The benefit would be that a well-made bolted joint is unlikely to be questioned by the IVA inspector, while still giving you the ability to dismantle the roll bar in the future.

Just my 2p's worth!

David


good point David

not doubting your suggestion as yes it is another alternative , its just that when i saw that photo as said in my first post it got me thinking , Hmmmm like the look of that,
as today i,ve been trying to get the "fishmouths" of the back stays to match the actual roll bar & i,m finding it a bit ermm "a pain in the jacksy"

my plan is to join my back stays more or less in the bend of the roll bar down to the bottom corners of my chassis & so the fishmouths are not equal in the points where they meet the roll bar, ( hope that makes sense )
so yes either as you suggest or the rose joint idea would make fabrication alot easier, imo of course.
just wasn,t sure if for the new IVA regs rose joints would be allowed in the roll bar.

cheers
andy

Howlor - 24/7/09 at 09:14 PM

Some of the roll bar manufacturers sell the weld on ends for correct removal stays.

For safety these would be the best option IMO.

Steve

paulf - 24/7/09 at 09:19 PM

Ive seen them done with rose joints but never felt it looks to great, If the stays can pivot it surely cant be as strong as a solid welded joint.
Paul.

RichardK - 24/7/09 at 09:36 PM

Andy, have you got a little program for the pc called tubemitre, download it from here LINKY fill out the fields, print it out, and then cut around the solid line. Wrap it round your tube, mark off and cut it out.

Piece of cake mate.

Cheers

Rich

lsdweb - 24/7/09 at 09:40 PM

Rose joints won't be acceptable if you decide you want to compete at some point in the future.

handyandy - 24/7/09 at 09:53 PM

Thanks guys,

sorry , just been doing some searching on google,

i,ve found some "weld in " clamps/adapters that look nice & solid, only £7.41 for a pair,

these would make it easier to fit the backstays as i said above, they are not going in the usual/popular place on the horizontal bar but in the bends of the bar.
looking at the clamps i think these would look tidy & are proven as strong.

Thanks Rich, i,ll download that linky as might come in useful too .

i have no intention of competing in my car, tho a track day or 2 each year will be on the cards i,m sure.

cheers for all suggestions, appreciate them

andy

SPYDER - 24/7/09 at 10:14 PM

Hi Andy. We have used rose joints at the lower end of the removable rear stays on our Phoenix in addition to a full cage. Joints are 1/2".
Geoff.

handyandy - 24/7/09 at 10:32 PM

thanks Geoff,
that looks smart

may i ask,
would i need to buy pre threaded inserts to weld into my back stay tubes for locating the rose joints or just tap a thread into the tube?

1/2 inch is pretty substantial & so imagine it is strong enough for its purpose.

cheers
andy

ps... tanks nice too

[Edited on 24/7/09 by handyandy]

eccsmk - 25/7/09 at 12:17 AM

sorry a little of topic but
how would the rose joints hold up if the car rolled over??

im not having a dig i'd like to know if they would hold ok (for another project of mine )

handyandy - 25/7/09 at 12:21 AM

quote:
Originally posted by eccsmk
sorry a little of topic but
how would the rose joints hold up if the car rolled over??

im not having a dig i'd like to know if they would hold ok (for another project of mine )


fair question, sadly i don,t know the answer either so if anyone can give any input i,d appreciate it too.

andy

snapper - 25/7/09 at 07:36 AM

The IVA now tests external and internal areas in an open car for radius and sharp edges

SPYDER - 25/7/09 at 09:59 PM

quote:
Originally posted by handyandy
thanks Geoff,
that looks smart

may i ask,
would i need to buy pre threaded inserts to weld into my back stay tubes for locating the rose joints or just tap a thread into the tube?

1/2 inch is pretty substantial & so imagine it is strong enough for its purpose.

cheers
andy

ps... tanks nice too

[Edited on 24/7/09 by handyandy]


Hi Andy.
We made our own threaded inserts and welded them into the tubes. The rear stay tube is 3mm wall thickness.
We realise that using this overall approach, ie. using rose joints and ally tube, may not ultimately be as strong as using steel but the rear stays are, in our case, in addition to a full cage, again of our own design and manufacture. (Apart from the bending, done to our spec by Martin Keenan.)
The cage features fully "fishtailed" joints and some nifty gusseting around the top tubes. Took ages to do, but worth it, we feel. And strong enough, we hope!
As regards rolling the car over as suggested (and who knows..) I would think that the loads in the rear stays should be along the length. I may be, and probably am, wrong on this one.
I put my faith in the cage as a whole and my mates welding, which is second to none.
The cage doesn't look as tall with the bodywork on. Thankfully!
You may be able to buy steel threaded inserts from a roll cage manufacturer.
Geoff.

The following pics show the cage at various stages of fabrication and are posted to help, inspire, or possibly put off any budding cage builder. The design is untested and may not conform to any regulations. Copy any part of it at your own risk.
We think it's OK though!




kj - 26/7/09 at 10:01 AM

Hi Andy,

I know it can be a pain when doing the roll bar down stays and cutting the fish mouths, what i did in true low cost fashion was use a kittchen roll tube then when happy with the angles etc transfer it to the roll bar stay.

handyandy - 26/7/09 at 11:35 AM

thanks guys, those pictures look good, very tidy job & looks strong too,

KJ.... thanks for that, me being thick of not thinking of such a simple idea, i,ll give that a go before i revert to plan "B".

thanks
andy

procomp - 27/7/09 at 02:47 PM

HI

I think it is worth mentioning that The FIA/MSA have made cages with rose joints fitted non compliant for there regulations. Also worth noting that more and more trackday companies are insisting on FIA/MSA rollbar / cage specifications also.

Cheers Matt

MikeRJ - 28/7/09 at 04:14 PM

I'm struggling to understand what advantages a rose joint offers over a simple bolted joint?