This is topic anti submarine belt? in forum Spec Miata Safety at Spec Miata Community.


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Posted by SnakeFart (Member # 2235) on :
 
where should this be installed at? in the GCR it says should be as close to the drivers chest. that would mean i need to drill a hole in the car under the seat.

if i do that i need grade 8 bolts correct? where do i find those at?
Thanks in advance
 
Posted by Jim Boemler (Member # 371) on :
 
Mine is installed just forward of the cross-bar, although just aft would work as well. Partly depends on your seat position. With most seats, the hole will guide the strap to the proper position.

I used a grade 8 bolt, but it's really overkill. I think the GCR requires grade 5. Locally I find them at either Tacoma Screw Products or Lowe's, but any industrial supply house should be able to set you up.

jim
 
Posted by SnakeFart (Member # 2235) on :
 
ah yes it does say grade 5 so i guess i could head to the local hardware store and buy 1. as long as its attached to the car metal to metal it should be ok to pass tech i assume.
 
Posted by Jim Boemler (Member # 371) on :
 
Use a big thick washer underneath. Like a couple of inches. I use a heavy "fender" washer, backed up with a large hardened washer. Point being you want to spread the load as much as possible.

jim
 
Posted by jigou (Member # 336) on :
 
I picked up a hunk of 2" x 1/8" steel bar stock at the local hardware store, and cut square mini-backing-plates from it. Just hack off a hunk, drill a hole and mount it.

They held amazingly well when I wall/car-tested them.

As for the sub belt, I situated mine so it was pulling as directly as possible against the upward pull of the shoulder belts. Mount your lap belts low across your hip bones, get the shoulder belts where they need to be, then locate the sub belt.

Jarrod
 
Posted by SnakeFart (Member # 2235) on :
 
i have a cam lock on my harness do i want to have the locking part on my bellybutton or below it?
 
Posted by Jim Boemler (Member # 371) on :
 
If you've already bought your harness, you don't have much choice. The part of the buckle with two slots (for the shoulder harnesses) has to go "up".

Given my druthers, I 'druther have the lever pointed down, 'cause the sharp pieces of some levers (Simpson) poke me in the belly.

If I lost some belly, it would be less of an issue. [Frown]

jim
 
Posted by jigou (Member # 336) on :
 
You'll want the cam mechanism itself located below your belly button - so that your two lap belts run as straight as possible from the cam lock, across your hip bones, and down to their mounting points.

If the belts are above your hip bones, then you're relying on the squishy part of your belly to hold you back in an accident, which is not a good thing.

Jarrod
 
Posted by sungod1971 (Member # 2600) on :
 
If memory serves me correctly, SportsCar published a series of two or three articles in 2004 detailing correct/optimal installation and positioning of belts. For back issues, visit:

http://www.sportscarmag.com/customer_service.asp?type=back

--Best from, Mark Lee