ORX705

installing a 4-pt roll bar with a cross bar which extends from the top right corner to the left support arm (see attachment, not quite sure on brand) and am considering modifying the 2 support arms


the usual 2 points bolt to the rear foot wells. the other 2 (support arms) i'm a little uncomfortable with; they bolt to the rear wheel wells just below the strut tower. i was considering attaching them to the top of the strut towers which would is a stronger support area but would change the angle of the support arms close to perpendicular (~70deg to 80deg) to the main bar. this may limit the resisting force of the roll bar in the case of a roll.

what are your thoughts?

macdaddy

The 2004 SCCA GCR specifies the rear braces shall be attached at near as possible to the top of the main hoop not more than six (6) inches below the top and at an included angle of at least 30 degrees. I don't know the relevant Australian sanctioning bodies and their rules, but the SCCA is generally pretty well respected as far as safety specs.

ORX705

thanks macdaddy,

does this mean it needs to be greater then 30deg from the main hoop?

and out of interest is the SCCA GCR drag strip or track rules?

Travis R

The GCR is for road racing.
The angle needs to be more than 30 degrees. They are trying to ensure that the attachement points for the support bars are far enough away from the base of the main hoop. If the support bars attached right behind the main hoop, making an included angle of just 1 or 2 degrees, then in a roll over the hoop could easily be pushed over.
Taking the support bars to the top of the strut is a great idea.
Good luck

ORX705

Thanks Travis, that's all the convincing i need. i shall begin

Silkworm

But if you're going to go that far, strongly think about mounting it to the subframe rather than the floor pan.

PaulC