New seat belts

[Skittler]

The weather was nice so I was in no rush!
After a month or so sitting in the garage the new seat belts have finally made it onto the roadster.
Not a particularly difficult task just taking the whole back off in order to access the rear cross member.
So three days of enjoyable deconstruction and then reconstruction.

[stevejgreen]

Re: New seat belts

It would be interesting to see pictures of the mounting, presuming you took some.
Did you go for inertia reel over fixed?

[WendyEJ]

Re: New seat belts

I would be interested in seeing some pictures too. My Marlin is fitted with static belts at the moment which don't match and I'd love to upgrade to inertia reel ones. From what I can see there are three fixing points for each belt - one in the rear and one at each side of the seats. Would there need to be another fixing point at shoulder level (like modern cars) or could I still fit inertia reel belts with just 3 fixing points?

[stevejgreen]

Re: New seat belts

Ideally the over-shoulder seatbelt should be mounted at shoulder height, something that is not going to happen given the rear cockpit height. But provided you can create a structurally strong mount, preferably secured back to the original seatbelt fixing deep in the back of the boot space, things should be OK but will never be entirely satisfactory.
I will try to look out my pics in the near future but a first look through my docs does not reveal them, maybe they are lost in transit and will resurface later. That's why I was hoping for pics of another installation.
What I ended up with was a snug fitting post between the cockpit rim and the shock absorber mount transverse beam to which it was securely welded and bolted, with an aforementioned strap bolted at both ends to the post and original mount. A bracket was then fabricated to mount the inertia reel so that it operated correctly.

[b_caswell]

Re: New seat belts

This drawing may help

[ggrum]

Re: New seat belts

Exactly what I did in my Roadster and works well, although never put to the ultimate test fortunately.

[stevejgreen]

Re: New seat belts

This drawing may help

Thats pretty much where I started from but, its only the later chassis that had the angle bracket welded between the shock mount beam and the sides.
All the bolts specified are 7/16 Unf (apart from a 1/2" one) these are the standard seatbelt fixing bolts at the time and should be all HT bolts.
On the question of seatbelt shoulder mount height, I am not sure that this Marlin design would meet current IVA regs. Perhaps someone can advise further for those wanting to build an unfinished, unregistered kit of parts.

[DaveTrials]

Re: New seat belts

On the question of seatbelt shoulder mount height, I am not sure that this Marlin design would meet current IVA regs. .

There are dimensions from seat base to height of mounting point in the IVA regs. It should also be noted that a document is submitted by the manufacturer of the chassis showing that the mounting points have been load tested. This makes it simpler for a pass. I am not sure how you could prove the strength if your chassis has not been tested.

[b_caswell]

Re: New seat belts

Having crash tested a roadster to the extent that it bent the front chassis back 6 inches with two adults in the car I can assure you the original seat belt mountings worked OK just a few bruises where the seat belt pulled on soft tissue. The impact was such that the six cylinder engine tore the engine mountings on the chassis and went forward two inches.

[cameronfurnival]

Re: New seat belts

There are dimensions from seat base to height of mounting point in the IVA regs. It should also be noted that a document is submitted by the manufacturer of the chassis showing that the mounting points have been load tested. This makes it simpler for a pass. I am not sure how you could prove the strength if your chassis has not been tested.

In order for it to pass IVA not only will the shoulder height have to be correct (above the seat base) but that hole through which you bolt the inertia mechanism, the one which goes through the 1" square tube needs to be sleeved! yes really! ANd all bolts would have to be high tensile Just thought I would add for completeness.

[Mike]

Re: New seat belts

At my IVA test the inspector asked me to remove one of the top seat belt mounting bolts to check the threads and depth into the mounting point.

For me, this was one of the things I was pleased to see in the IVA test, as it is absolutely safety critical.

Out of interest, I attached my seat belt fixings directly to my seats in my Cabrio - they were taken from an Audi A4 and I used their standard fixings points. The inspector then made sure I had fitted the my seats to the floor using spreader plates underneath, and that the floor was suitable for the purpose.

Mike