I'm just about to go to SVA, an have realised that my rear seat belt mounts are too low, even though they are on top of the chassis rail.
So I need to raise them, by about 50mm. The only way I can see of doing this is running a rail from either side of the roll bar like this:



If you cant see the image then (click here)

Is this both safe and SVA compliant. My concern is that there isn't much support for the single bar accross the back, and that the RHS will just buckle under extreme load(i.e. sudden jolt forward).

I don't really want to get the welder out as my welding is rubbish.

What other ways of doing it are there?

[Edited on 28/9/06 by RobBrown]

SVA will assess the overall strength of the mounting points. If you look in the manual there is guidance on how to make the assessment.
Where the belt is bolted to a roll cage they look for bracing, triangulation, welded joints and 45mm x 2.5 CDS or 50 x 2mm etc.

I think your best bet would be to weld a tube the same diameter as your roll bar in the place you show your RHS and back brace your roll bar unless braced already.
See here:
http://www.locostbuilders.co.uk/viewthread.php?tid=49580

Another option would be to weld vertical RHS posts to your top chassis rail with eye bolts screwed in the top. I think others have done this and passed OK.
Not quite like the link in the first post here but similar.
http://www.locostbuilders.co.uk/viewthread.php?tid=51625
There must be some other posts about it.

HTH

David

[Edited on 28/9/06 by DavidM]

[Edited on 28/9/06 by DavidM]

Laterally thinking, you could always lower the seat with a recessed seat pan - I did this to gain a little more headroom in my middy.

When you consider the fix just bear in mind you may introduce other discussion points.

Lowering seat may make the top of the wheel interfere with view of the road.
Moving belt mounts to roll bar will mean roll bar is structural and must be secured in a certain way.

You can buy threaded bars to weld onto the chassis to lift the height. I know some have bought from Mac#1 for example.

When you say you are just about to go to SVA, does that mean you are there right now? If so then i guess you didnt have time to change them. It probs wasnt a quick fix item anyway.

I'm pretty sure SVA gives the g force that the belt system must be suitable to survive.

IIRC it's something like 20G ie. 20 times your weight.

If you and your passenger weight is 150kg total then you are looking at a force of 3000kg.

And you want that relying on 2xM10 bolts do you?


Do it properly.... get it welded.

All the best,
James

quote:

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IIRC it's something like 20G ie. 20 times your weight.

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This is why I ask.

I want to make sure whatever is done is done correctly and doesn't compromise safetly.

The idea of small towers welded to the top of the chassis, doesn't fill me with confidence.

I can't do anything about it now,as SVA is on Tuesday, so will discuss it with them, as well, if it crops up. You never know it may pass on that point (but I doubt it)

Rob