Ive read postings here and other places saying that a rollcage in a dual purpose road/track car will add risk on the road due to potential for non protected head collision (not wearing a helmet on road or using a harness)
I get the fundamental idea that a 3 point seatbelt will allow more body movement which could make the likelihood of head to rollcage collison higher than if a harness is used.
Im an engineer and so tend to over think things over/through - so heres my thoughts on this - Im posting here to see what people think in case ive missed something or just to get general feedback/opinion.
Some background:
The rollcage Im looking at is a JAF approved cage that doesnt have a diagonal roof bar. See attached (roof not fitted).
So here we go:
The side bar (running across the door top) is running flush to the roof line so effectively in the event of a crash the head is now a few inches closer to an imovable object. My thinking on this design rollcage is:
Head impacting to side bar:
1) Im wondering if you will actually sustain less head injury from contacting with a foam covered bar than you will a fiberglass hardtop. (try hitting your shin with a piece of 4x4 with or without a thin foam cover and see what a big difference even a thin foam covering it makes) Theres only a few inches of clearance between the head and roof anyway so your heads going to hit the roof anyway. Im wondering if having less clearance and having a foam to cushion the impact could actually be benficial.
2) The closer proximity to the head will mean less momentum is built up (by the mass of the head as it moves) before it contacts - which I suspect would reduce injury to the head and the reduction in torque may help reduce extent of neck injury.
Head impacting to front cross bar (across windscreen top):
1) With no rollcage your going to headbut the fiberglass roof/screen top trim. With one, your going to headbut a foam covered bar. I guess the roof trim (if fitted) is going to provide some cushioning (as it is foam) (As mentioned the JAF rollcage has no diaganol across the top.)
So basically Im assuming some benefit in case of side movement of head and regarding forward movement Im assuming if the cushioning (padding) on the rollcage provides as much or more cushioning than the (foam) screen/roof trim panel then no additional risk. If a harness is used (on the road) then risk of impact to front bar is zero anyway.
So basically Im considering getting the JAF cage fitted and either using a harness if I cant suitably pad out the bar to match the cushioning of the roof trim or a 3 point if I can.
One other consideration is average road speed is 10miles per hour around Tokyo
I would benefit from rollover safety on (and off) the track. Having just sat through more footage of rolling cars (with drivers walking away) Im seriously interested in weighing up the pros and cons.
Id be interested in anyones thoughts, feedback and/or corrections to my logic.
I get the fundamental idea that a 3 point seatbelt will allow more body movement which could make the likelihood of head to rollcage collison higher than if a harness is used.
Im an engineer and so tend to over think things over/through - so heres my thoughts on this - Im posting here to see what people think in case ive missed something or just to get general feedback/opinion.
Some background:
The rollcage Im looking at is a JAF approved cage that doesnt have a diagonal roof bar. See attached (roof not fitted).
So here we go:
The side bar (running across the door top) is running flush to the roof line so effectively in the event of a crash the head is now a few inches closer to an imovable object. My thinking on this design rollcage is:
Head impacting to side bar:
1) Im wondering if you will actually sustain less head injury from contacting with a foam covered bar than you will a fiberglass hardtop. (try hitting your shin with a piece of 4x4 with or without a thin foam cover and see what a big difference even a thin foam covering it makes) Theres only a few inches of clearance between the head and roof anyway so your heads going to hit the roof anyway. Im wondering if having less clearance and having a foam to cushion the impact could actually be benficial.
2) The closer proximity to the head will mean less momentum is built up (by the mass of the head as it moves) before it contacts - which I suspect would reduce injury to the head and the reduction in torque may help reduce extent of neck injury.
Head impacting to front cross bar (across windscreen top):
1) With no rollcage your going to headbut the fiberglass roof/screen top trim. With one, your going to headbut a foam covered bar. I guess the roof trim (if fitted) is going to provide some cushioning (as it is foam) (As mentioned the JAF rollcage has no diaganol across the top.)
So basically Im assuming some benefit in case of side movement of head and regarding forward movement Im assuming if the cushioning (padding) on the rollcage provides as much or more cushioning than the (foam) screen/roof trim panel then no additional risk. If a harness is used (on the road) then risk of impact to front bar is zero anyway.
So basically Im considering getting the JAF cage fitted and either using a harness if I cant suitably pad out the bar to match the cushioning of the roof trim or a 3 point if I can.
One other consideration is average road speed is 10miles per hour around Tokyo
Id be interested in anyones thoughts, feedback and/or corrections to my logic.
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