nanotech wrote:I've wondered this for a while now and there seems to be little point making a new thread for this question when we have a perfectly good active one right here
Why do Australian mx5 roll over bars mount on the rear parcel shelf? After seeing many international half cages, 90% of have the diagonal bars passing through the parcel shelf and onto more structural parts of the car. Seems like that would make more sense too as the parcel shelf is very thin and can be quite easily cut through.
I would surmise in a roll over event, the parcel shelf wouldn't be able to handle the load and would crumple. Especially if the car is put into the air and dropped upside down. Now keep in mind I have no engineering background so I have no idea if the parcel shelf would indeed be strong enough. But based on the thickness and so on, I don't why this is the chosen mounting point for us in Aus.
Factor in that most international cages and half cages for Miata's require modification to the parcel shelf so the diagonals can pass through, why is Australia different?
To me, it looks like the Hard dog bars and so forth would be a safer alternative to a BD or Plus bar. I'm not trying to undercut forum sponsors here and I have the utmost respect for our domestic market and our economy; but after some shipping ressearch, the Hard dog hardcore bars seem to be only $800-900 shipped to your door internationally. There are countless photo's of mx5's destroyed with this half cage in place, which would show that they do indeed work... quite well!!!
Which makes me wonder why our domestic manufacturers haven't copied this design. Could it be that CAMS have restrictions on the possible mounting places for our roll bars? I've read into the CAMS specs for half cages a while back but it's been forever since I've glimpsed so I don't recall specifics other than mounting at the seatbelt bolts, having at least one cross bar and two diagonals and that it must be constructed from steel.
And another question. *flame suit on* I know that this has been covered countless times but I'm still yet to see someone with a logical answer. Why are alloy bars considered unsafe? As I understand, the wall thickness of the alloy bars are greatly thickened so it will theoretically be as strong as a steel bar anyway.
As far as I recall, alloy bars have been used in racing for decades anyway.
Would anyone be able to shed some light on this?
Just been doing some more "research" but I understand that the torque bar is suppose to compensate for the fact that the bar bolts on to the rear parcel shelf. MX5+ reopen next week. I will contact them and ask them this question and post their reply. So far, the MX5 + twin hoop I think is the go, especially given the later post regarding the attraction that a single loop attracts (not that this is the prime issue).
When did he do that?
