Hey, guys:
Personally, I don't think the "bolt-in vs. weld-in" issue is really the
point. One can mount the bolt-in bars with the backing plates, such as with
the AutoPower units, and the mounting points become pretty solid. To me,
the real issue is the bracing of the roll bar. I wouldn't even think of
getting serious about getting on the track without at least the competition
AutoPower unit with the diagonal brace. However, that's just the starting
point. If you want real safety, then the bar has to braced against fore and
aft movement. This requires a brace running from the top of the bar to the
passenger floor of the car, ala 289 Cobra. I also take issue with the rear
braces on the commercially available bars; they act as rear mounting feet
but they only go about half way up the back of the bar. You're only going
to get real strength if those bars start at the top hoop of the main bar and
extend rearward. Can you really imagine what would happen if you rolled
your car at speed, carrying a lot of forward momentum as it rolled? As soon
as the weight came down on the "show bar," the forward momentum would stress
the bar to the point that it could bend or break right at the top of the
rear mounting posts, thereby allowing the car to come all the way down on
top of it's occupants. Having the bracing run from the top hoop in a
forward and rearward fashion would prevent that from happening.
I realize that there is probably not a commercially available roll bar with
all of these attributes, which is why I had one professionally built for my
old Alpine vintage race car. Believe me, that was the strongest part of the
car by far!! If one must install a bolt-in unit, my recommendation would be
to have a forward-facing brace welded to the front of the main hoop and
extend it into the forward right side of the passenger floor at the point to
where the floor meets the side of the car. From there you could bolt it in
if you wanted to. I would also highly recommend that you weld in some
proper rear-facing braces from the back of the main hoop. This may require
some interesting engineering, depending upon where you want the bottom
attachment points to be. However, since I would assume that these roll bars
are being installed to protect lives, a little modification here and there
to get the bracing to fit would be worth it.
My .02 worth,
Andy Walker
Edmond, OK
B382001600LRXFE
TAC #740
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