Posted 16 June 2010 - 08:56 AM
This is how i understand it. (possibly far from correct)
The way the clamps are made, they are welded to alternate side of the tubing. The tube sits completely within the clamps. The force will go through the tubing, more so than the bolts. While they are expected to provide some protection. The main force from an impact will be taken with the tubing or the welded bracket section (or clamp).
Each side of the clamp is welded onto the alternate tube. the force will more so, go through this and the opposing tubes/clamp, put in place to cope with the impact. Not the bolts.
A lot of design work is put into a roll cage, each tube and mounting point is designed to protect from impact in a certain direction, with others in place to strengthen its weakness as best they can. If forces where expected to go through the actual way its held together, we'd be using bolts a lot bigger.
If you are still unsure of the safety there is a video somewhere of Chris in a 90mph+ shunt on track. I'm sure there have been many more too. My point being, these things are tried and tested, raced, dragged, driven and even crashed. They are an out and out pedigree, and Chris is very good at what he does. If you are still unsure, perhaps Chris will be able to explain further and better than I am able to.