Author |
Message |
dixonmanor Samba Member
Joined: June 09, 2006 Posts: 73
|
Posted: Fri Aug 18, 2006 11:53 am Post subject: I need some advice (sorta quickly) |
|
|
I have the opportunnity to pick up a nice pair of leather racing buckets on the cheap. I know this has been discussed, but I'm still not clear on whether or not it's feasible to bolt the rear, over-the-shoulder parts of a four-point harness to the floor of a Thing.
Thanks! |
|
Back to top |
|
|
TLW54 Samba Member
Joined: February 24, 2005 Posts: 70 Location: Castaic, California
|
Posted: Fri Aug 18, 2006 12:59 pm Post subject: |
|
|
One thing to remember is that using 4 or 5 point harnesses, you will need to run a bar from each side of your roll bar at about 3" below your shoulders. If you attach the shoulder straps to the floor they will not be effective and can cause more major injuries than protecting you. The shoulder harnesses are to keep you from going forward, while the lapbelts keep you in your seat when you go upside down and hold your lower body from ging forward. The fifth belt is to prevent submarining, sliding under the lapbelt. If you just mount the shoulder harnesses on the floor they really don't help that much and the stresses placed on your neck and spine can (in a major hit) cause major trauma. |
|
Back to top |
|
|
dixonmanor Samba Member
Joined: June 09, 2006 Posts: 73
|
Posted: Fri Aug 18, 2006 2:49 pm Post subject: |
|
|
So, basically, shoulder belts on a Thing are out of the question unless I want to modify the roll bar? Isn't mounting to the roll bar unsafe in itself?
This is all still new to me. |
|
Back to top |
|
|
Captain Spalding Samba Member
Joined: February 19, 2005 Posts: 2519 Location: . . . in denial.
|
Posted: Fri Aug 18, 2006 4:18 pm Post subject: |
|
|
dixonmanor wrote: |
So, basically, shoulder belts on a Thing are out of the question unless I want to modify the roll bar? Isn't mounting to the roll bar unsafe in itself? |
Speaking purely from a common sense perspective - you want to have the shoulder belt mount at shoulder height or slightly higher. If it's lower, you risk spinal compression as has been mentioned several times. I think even 3 inches lower is not optimal.
As far as mounting the shoulder belt to the roll bar - there are two circumstances in which that could pose more of a risk than having no shoulder belt at all: if the roll bar deforms during the crash, or if it pulls out of the floor. In either case, the issue is the belt crushing the occupant, either across the chest or the neck.
The beefier your roll bar is, and the more triangulation it has, the less apt it is to deform. In the case of pulling out of the floor, the weak link is the sheetmetal floorpan itself. The larger the foot on the upright of the bar, the better. Use a backing plate under the pan, so that the fasteners can't be ripped upward through the sheetmetal.
There are two ways to mount the high point of the shoulder belt. The bar can be drilled, and then a crush sleeve welded in (this will replace the structural integrity in the bar which was lost by drilling it. Or a tab could be welded to the bar. I would gusset the tab also, to keep it from rotating forward. The advantage of a tab over drilling and sleeving the upright is that it moves the shoulder belt mount slightly rearward, behind the occupant and away from the head.
Of course, grade 8 or equivalent fasteners all around.
The commentary in the image below is relevant to another thread in which this topic was discussed at length.
|
|
Back to top |
|
|
|