roll bar
 

Hi could anyone tell me if it matters with IVA if my head sticks above the roll bar i purchased a roll bar from Ash a long time ago and recently have been mocking up my seats and harnesses and when sitting in the car i think my head is close to the top i am 6'6',don't want to start welding only to find it fails iva? and am i ok to bolt straight through the floor with the seat fixing bolts.
Any help would be greatly appreciated
Thanks
DaveyB

There is actually no requirement to have a rollbar at all for IVA.If you have one then i personally would want it to offer some rollover protection so it will likely need to be taller to offer this.I recall Spud was about 6'6" and had to have his made larger.
With regards to the seats i see it this way;if you have a steel floor welded in then bolt it through it.If you have an aluminium floor riveted on then i would put in support strips of 5mm across the 450mm width.

I have upgraded the strength of the bolts in my roll bar to M10. Does anyone know if any cars have passed IVA without rear stays. I haven't got them on mine. I was looking at the GBS zero and theirs seem to be more for cosmetic reasons as they bolt into an unsupported alloy rear panel.

Thanks for the reply, do you think it will be ok to weld some additional 50 mm tubing to the bottom of the roll bar to archive some extra height without ruining the integrity of the roll bar from its original form?
I was thinking of placing the seats on some 5mm plate could I just drill and tap the holes for fixing them or should I still drill straight through.
Thanks again for the help
DaveyB

If you must lengthen it,it would be sensible to strengthen it with some tube inside it and weld all three parts together and also make a hole in the mounting plate and place the tube through and weld underneath too.

Personally I wouldn't. The roll bar is there to help protect your bonce. IMO, if the welding is ever so slightly off, you've introduced a potential fatigue point if the worst was to happen.

WRT rear stays, I would incorporate some into the design. If you look at any functional roll cage (be it in a sevenesque or saloon car) you have a pair of functional stays.

Yes, you could theoretically have a single hoop rollbar. However, it would have to be substantial to be of as much use IMO.

I agree if god forbid you flipped it is the only thing that would keep you alive the stronger the better IMO I might have a friend who has a hoop that is longer its 50mm tube and it's nicely bent he was the guy who lent me his Cnc bender for my bar

Hi well thanks for the replys I did wonder about modifying the bar and it still being suitable.so thanks for the help , I think I will have to consider a completely new bar. I will concentrate on getting the seats in position and will then be able to work out exactly what height I will need. Thanks again
DaveyB

Hi Davey,

Time to be really cheeky :D

If you do decide to go for a bespoke, made to fit rollbar, does that mean you'd have a book spec one up for sale?

I always think it's good to get in early on any cheeky deals ;)

Having thought about it a little perhaps won,t sell, I was wondering
About putting a tube like a sleeve around the 50 diameter
Have seen some 60 mm tube with the right bore I could extend it welding the outside and inside only need to extend about 2/3 inch will it matter if the outside diameter is a little bigger where the cross bar goes for the seat belt positions it won't be much if you get my drift.

Thanks
DaveyB