Henry,
I've been looking into the harness situation lately. The SCCA is allowing
2 inch FIA but NOT SFI shoulder belts only when used with the HANS
device. For a lap belt the argument seems to be that a 2 inch belt fits a
human body in the hip / pelvis area better and can be tightened 1.5
inches tighter than a 3 inch belt effectively making it act sooner in a
sudden deceleration. Any use of a 2 inch belt for lap or shoulder belt
looks to require FIA approval. I am trying to find documentation of the
difference in strength and construction of FIA approved and SFI approved
2 inch webbing. What I have found thus far, if you want the strongest
strap, buy a winch strap.
The Impact Racing harnesses are polyester and have less stretch and other
improved properties.
The graph that shows the deterioration of nylon webbing supports the
conclusion that my harness is long past 100% loss of tensile strength. As
yet no one who accepts the claim completely will attach the lap belt to
the ceiling, wrap it around their neck, jump off a chair and prove that
100% loss. I'm confident my belts are capable of ripping the "Approved to
British Standards" attachment points from he car.
The argument that the nylon looses its stretch to attenuate an impact is
shot down by the polyester webbing starting life just that way.
This is a serious can of worms. Right now is a tough time to be in the
market for a restraint system.
Bill
On Fri, 28 Apr 2006 09:29:38 -0400 "Henry Frye" <henry@henryfrye.com>
writes:
> The harness in my car has reached maturity, in May it is 5 years
> old,
> time for a new one. Looks like I am going to buy an Impact Racing
> system harness.
>
> It has been a while since I did any research on harnesses, but it
> seems
> to me there are a couple of things that make good sense.
>
> I use a HANS device. I can get a harness from Impact that has 2
> inch
> webbing above the shoulder adjusters. The smaller webbing fits
> better in
> the groove the HANS device uses to hold the device on. That,
> combined
> with a Sternum Strap, seem like it will really help keep the HANS
> device
> in place if I ever need it, especially in the case of an impact from
> the
> side.
>
> I think some regs still require 3 inch wide belts. There was a long
> thread on the VRG list where someone said FIA may have adopted 2
> inch
> wide webbing.
>
> Thoughts???
>
> Jack W., how would SVRA Tech view this harness setup?
>
> Thanks guys and gals!
>
>
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