Static 3 point rear belts

[Gengis]

I want to fit static 3 point seat belts in the back of my Vitesse convetable. Has anyone got any pictures of frame work that they have made to attach them safely? I know there’s a company London way that makes frame work up for them but it is bit of a trek for me. Thanks

[Clive]

The issue is that in the event of a crash, the upper mounting needs to be extremely strong. The company you refer to dies use a frame, but the photos I saw show it has not been designed to withstand significant forces. I would not use it....

I had a vitesse CV and small children (now big) and we used simple lap belts. I kept thinking about building a framework behind the side panels, replacing the existing pressed frame with 25mm box section and diagonals from the top corner down to the bottom of the b posts. And a stronger section behind the seat, probably 50x25 plus X bracing. Would have been tricky as space is so tight. But I would not use 3 points unless that upper mount was going to survive a crash.

[TomL]

Clive is absolutely right; it is difficult to achieve the upper-mount for three-point seatbelts in a convertible Herald/Vitesse.

I constructed a steel frame to fit behind the (non-standard) rear seats, allowing me to fit inertia reel belts, but it wasn't exactly the work of a moment.  It's all very tight with the hood-well, which of course, you cannot obstruct.  I mainly used 25mm box section but there's other bits of steel in there too.

[Clive]

That is the sort of thing. But Tom has a rollbar, I was thinking bringing the "forward strut" down to the bottom of the b post, and as above, replace the hood well frame with box.

But all different ways of doing a "proper job" but it is either DIY or rather expensive, especially as a company should provide some sort of certification. 

[NonMember]

I haven't done the calculations but my gut instinct is that Tom's solution is MAHOOSIVELY over-spec'd. The standard front belts are anchored to the wheel-arch, which isn't that strong.

Think about it. In the event of a seriously major head-on, you're trying to restrain a person, not the whole car. And you don't actually mind if that person moves by, say, six inches, you just need to avoid hitting the front seat line. And the car's written off. So it's not necessary for your framework to survive completely unscathed. In fact, if it crumples a little, it helps to reduce shoulder injury.

[Gengis]

Thanks for the advice