RE: Removable Spider Roll bars

["Brian Shorey" <bshorey@domain.elided>]

Couple of comments:

> mounting bolts ran through the package sill area, then through reinforcing
> plates plate under the car (this was to wrap the bar mounting around a
> section of unibody construction, rather than just to the top). My current
> car has a bar that bolts to tapped plates welded on the top of the sills.
> I'm thinking the base must be "through bolted", not into a top mounted
plate
> (regardless of how sturdy it's construction), but this may not be
correct..
> Comments?.

Simply welding to the parcel shelf is not enough.  On mine we also went
across the front of the parcel shelf and welded to the vertical section
there, and on the outside edges we welded to the vertical surface of the
inner body panels.  And, fwiw, we're not relying on just the pads - the
fore/aft bar adds significant strength to the entire assembly.

>  I, too, want a street/track bar and have wondered how to address the
helmet
> clearance requirement issue. While rules seem to mandate a continuous hoop
> mounted on the frame/body, I wonder if a (top-clearing) shorter removable
> hoop could be mounted in upright tubes, and then raised when needed with
> spacers that would slide into the bottom of the uprights. These would need
> to be solidly made, and as strong in vertical strength as a hoop butting
on
> the frame/body.

I've seen one such solution, and quite frankly I wouldn't trust it.  Aside
from the fact that it's not legal.

The main hoop must be one continuous piece.

Even if it wasn't, you have two problems:

1) If you make the break towards the base of the hoop, then the mounting
pads on the rear extensions won't line up in the same place when the bar is
raised or lowered.  The solution that I've seen was done with the bar in the
lowered position, and when he added the 6" insertions the rear extensions
ended up ruining his top window.  IIRC, this solution also involved four
pads for the rear extensions, two for the 'lower' position and two for the
'upper' position.

2) If you make the break above where the rear extensions connect to the main
hoop, remember that there is a 6" maximum extension for the main hoop above
that point.  And that's with an unbroken main hoop.

Paul learned this lesson the hard way - many years ago a customer of his
flipped a Giuletta with a bar Paul had fabricated (the bar was completely
legal).  Just as the car came to a stop the main hoop snapped just above
where the rear extensions connected, luckily the car had just come to a halt
and the driver was unhurt.

bs

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