Roll Cage rule clarification questions

[G-man]

On page 80 of the 2008 race rules, rule 3-D "A bar joining the outer members of the front hoop near steering column height is required."

What size of tubing does this have to be?
The same as the main hoop or can it be smaller and if so how small?
And does it have to be perfectly straight or can it be zorched for clearance?

Thanks in advance.

[CRXsi]

1 - Construction Materials
a) The main hoops and primary bracing should be constructed from round, mild steel, ERW
or DOM type tubing. Chrome molly tubing such as 4130, may be used but is not
recommended.
b) Aluminium and composite materials are prohibited construction materials for roll cage
structures.
c) All cages must have a 0.476 cm (.1875") diameter inspection hole drilled in each main
hoop.
d) Minimum tube size and wall thickness are as follows for vehicle weights including
competitor:
e) Under 1500 lbs 3.49 cm X 0.24 cm (1.375" X .095")
Under 2500 lbs 3.81 cm X 0.24 cm (1.500" X .095") or 3.49 cm X 0.30 cm
(1.375" X .120")
Over 2500 lbs 3.81 cm X 0.30 cm (1.500" X .120") or 4.44 cm X 0.24 cm
(1.750" X .095")

By the highlighted item I would say it needs to be the same as the rest of the main hoop tubing as well as all major primary braces and tubes.

[G-man]

Excellent, thanks for that.
I was unsure as to whether it would be considered primary bracing.

[CRXsi]

I would have to say it is primary bracing as it's main role is to prevent the cabin from crushing in the event of a major side impact towards the front half of the car. I would consider secondary bracing to be things such as gussets, window net mounts, steering column mounts (if applicable) etc. The primary roll structure should all be the same size.