I'm in the middle of doing my roll bar, currently the main hoop is of 38mm 3mm wall ERW

I know this size (I know it's not CDS) is sufficient for FIA / MSA cages but will it be ok for the SVA? The reason I ask is that in the manual it states that for guidance they should ideally be made of 45mm 2.5mm wall or 50mm 3mm wall IIRC, but it does state 'for guidance'

Does anyone have experience in passing a car with this O.D. of tube?

Stott

Erm, you don't need a roll bar for SVA! Andre just passed at Newcastle without one. See here when he was thinking about retro fitting one. http://www.locostbuilders.co.uk/viewthread.php?tid=74269

Also think of the number of cobras you see with no roll bars, or hoops.

Mike

Granted, but like wipers, windscreen, reverse lights etc, if it's fitted it has to be to spec.

Retro fit is not an option as the cage and its bracing form an integral part of the chassis strength so I need to be sure it will be ok before I weld it all up

There is no requirement for a roll bar for SVA.

If one is fitted then there are no specific requirements except the usual edge radius requirements etc.

If your seat belts or harnesses are connected to it then it has to be strong enough to take the load. There is guidance in the SVA manual if this is the case.

David

Thanks, I have the manual and have read the section relating to roll cages / bars and as stated above there are guidelines in it.

Just wondered if anyone had any negative experiences where an examiner had used his judgement to rule against the builder based on these guidelsines

Cheers

Ive seen em eld on with self tappers!

Not to mention manufacturers using unbraced single hoops aka the mousetrap.

Your chosen material will be fine - not MSA, but will certainly help if you ever end up inverted. Don't use self-tappers (had to force myself to type that word urg, horrible things for any job) use big high tensile bolts (8.8 12mm) through good sized plates if you must or better weld on.

Hi also it should be pointed out that for MSA/FIA use all rollbar/cages with an OD below 45mm are required to be cetificated IE fully tested.

cheers Matt