[DeTomaso] Asa's installing the roll cage

[MikeLDrew at aol.com]

In a message dated 1/30/10 17 34 37, guson at home.se writes:


> Carpet between cage and car: Big time no-no IMO.
> 

If the cage is just there for looks (as most of them are), then it's not a 
problem.   But if you're installing a roll cage with the idea that you might 
actually want it to function someday, then yes, you're absolutely right.   
It's critical that you get metal-to-metal contact between the feet of the 
roll cage, and the chassis of the car, which means the carpet HAS to go.

Car crashes can be incredibly violent things.   In an impact, the carpet 
would easily crush and allow the roll cage to move around.   There is a shear 
plane there, and the bolts could easily shear and cause the roll cage to 
come loose, rendering it useless.   That's one of the many things I learned 
(well, not about roll cages and carpet specifically, but rather more generally) 
when I went to the Air Force's crash investigation school.  We studied 
failures that led to airplane crashes, as well as failures that took place 
during the course of crashes, and one of the important points that was stressed 
was that when two things that are supposed to be bolted together are tight, 
they are strong, but when the bolts are loose (which is what they would be if 
there was carpet between them), they are incredibly weak, and the weak link 
is the bolts.

It would not surprise me if a roll cage that was bolted on top of carpet 
would fail tech, if the tech inspector noticed it.

Figure out where the footprint of the cage is on the carpets, mark them, 
then cut the carpet there.   If you don't want to leave the cage in place 
permanently, you can probably glue the carpet back in place on a semi-permanent 
basis, or come up with some other aesthetically pleasing solution.

Mike