SVA - seat belt anchorage points

alackofspeed · #1 2nd December 2007, 17:37

A very quick question:

Has anyone failed their SVA due to poor seatbelt mounting points? This is for inertia reels, not 4 point.

I ask, as I fitted my belts today, and to check the inertia reel worked, i chucked my weight (approx 85kg) against the belt whilst seated. All seemed fine, until i looked at the roll cage mounting point, and discovered it had bent!!!

SDMC001 · #2 2nd December 2007, 20:27

John

That concerns me, I have not applied that level of pressure on mine, and if I did it would be several k more.

When at SVA it was remarked how well made they appeared.

Steve

craig · #3 2nd December 2007, 21:39

John, I meant to ask you earlier have you mounted them on the lower front facing mount or the top mount??

Craig

alackofspeed · #4 2nd December 2007, 21:45

I mounted them the same way I've seen others mount them:

I'll concede that the design of the shoulder anchorage / guide I'm using isn't ideal (and for the record the bolt is only a temporary test bolt), so I'll flip the anchorage / guide on the belt, and then add some extra material to the roll cage mount. That *should* sort the problem... I hope.

The picture was taken on my phone, hence the low quality.

craig · #5 2nd December 2007, 21:48

Same as mine then John, Which bit has bent exactly? Looking at mine tonight you would have thought that front directional force would try to pull the mount forward not bend it.

Can you upload a close up pic?

Craig

craig · #6 2nd December 2007, 22:18

hmm not good!! I hope there is not any sva guys reading this thread haha we will all fail from now on.

On a separate note John, with my belts came a stepped washer that fits inside the hole (I think without looking) and also on top of the mount to allow for swivelling that is about 8mm thick?

Craig

limpabit · #7 3rd December 2007, 06:06

Hi John.

That's how mine are mounted

And I've given mine a hefty test before SVA. Have not noticed any bending.

Ric H · #8 3rd December 2007, 20:59

Hi John,
No SVA problems for me - mounted same as. As Craig said, I'd have thought the only load the mount should see in use is forwards so I'm not too concerned. Did you pull it downwards when you tested it and it bent?
Richard

alackofspeed · #9 3rd December 2007, 21:17

Didn't pull it downwards.

As for the force, the resultant is going to be directed through an imaginary point that bisects the angle between the length of belt going to the reel, and the other going over the shoulder of occupant, and down to the catch. So if you were to assume the seat belt as it goes towards the occupant's shoulder were parallel with the ground (which it isn't on my car, it actually points downwards slightly), then the resultant would be at 45 deg to the horizontal, hence the bending force.

I did exactly as decribed above - manually chucked my weight forward with a jolt just out of idle curiosity to see the inertia reel work.

Ric H · #10 3rd December 2007, 21:21

Good point! Thanks for the mechanics refresher :-)
Now you've got me a bit more concerned again...

alackofspeed · #11 3rd December 2007, 21:27

I'm not too bothered, as I'm going to adopt the crude approach of adding more material, and cross bracing it with the 4-point harness bar part of the bracket.

Yet another bodge to add to my score sheet!

Quote:

Now you've got me a bit more concerned again...

P'ah - if you worry about crash safety in one of these things you'll never drive it again! My only worry is passing the SVA, because I know if I have an accident of any merit in this thing, I'll have more chance of surviving if in old-skool-F1-style, I get thrown from the car and take my chances! [a little tongue in cheek...]