Not sure if this is a 'chassis' or an 'interior' thread so apologies if it's in the wrong place. I spent Saturday fashioning a jig to support my MEV GRP seats in my Haynes Roadster and trying out the seating position for size. The chassis I bought already had some lower harness mounts in place - but I am not sure if they are likely to be in the right place come IVA time given where i've positioned the seat. I am also having a hardtime deciphering the IVA manual requirements - does anyone have any tips on working this out?? Seems I just have to avoid the harness fouling on the GRP when i'm in situ with the belts done up?

The thing that REALLY confuses me is that I can't see any specific requirements about where the mounts are relative to the driver - e.g. lower harness mounts don't have to be behind the driver - although logic dictates that's the only way they'll be effective...?

Pic may help illustrate - the seat is about where I want to mount it...

I have no idea on the IVA rules.

However, in practice, the closer the lower mount is to your hip the better so that the belt it pulled 'down' more effectively.

My mounts are far too far backwards allowing the lap belts to ride up under the rib cage- potentially very serious in a front-ender.
Another job to sort out.

Cheers,
James

Heres a pic of one of mine Lower harness

IVA says you must be able to access and adjust the belt .. See where your adjusters are.. if you bury them behind - bellow the seat you may have problems..

[Edited on 15/11/12 by johnemms]

[Edited on 15/11/12 by johnemms]

I tend to agree. I think firther forward may be slightly better from comfort/safety point-of-view. Not sure about the IVA needs though.

quote:

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Originally posted by johnemms
IVA says you must be able to access and adjust the belt .. See where your adjusters are.. if you bury them behind - bellow the seat you may have problems..

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Position looks OK to me. Some edging on the seat should prevent chafing.
However whilst I'm sure it's strong enough I'd be happier with the captive plate triangulated off the chassis tube behind it.
That way it is less likely to twist under load.
Also if you haven't already bought them try to buy harnesses with pull-up lap straps.
I think Securon do them and they are so much easier to use, especially if you do events where the car is double driven - ask me how I know!
Cheers, Pewe10

hi my seat belt mounts are 140mm forward of rear crossmember if that helps .ps they did fail iva test first time but not for wrong position but not been gusetted .now passed iva

My opinion from my IVA tester from the picture that would fail..

I'm not sure if there is a picture in my archive of mine, but mine was a threaded bush welded to a triangle plate welded into the bottom and up right tube and mine failed....

The tester said he wanted to see the bush welded directly to the chassis rails, and gusseted. Dad being an MOD engineer did go though all options with the guy, that would still be as strong as they wanted but it still came to we had to weld the bush to the chassis and then we added an additional gusset over the top.

I always think the belt fixing point should be feather forward then yours more just in line with your belly so the belt is pulling down on your legs
Looking at your photo i would say where the white line is

[Edited on 29/11/12 by jacko]

Is there any way for builders to get 'official' feedback from inspectors prior to going in for IVA? Don't particularly want to get all the way to the test then find out that i need to start shifting things like these mounts...

yeah sorry but the bracket looks a full length too far back, you'll find that the harness will not want to sit over your hips but much higher up, not only will it be sore to use but you risk sliding under the harness in a crash. Sit in the seat and drape the harness over you, it should not be twisting from your hips to the mounting point, an angle back of about 45 degs in your case

if you try and look at the lower harness angle in this pic you can see just how much further forward your mount needs to be...



[Edited on 29/11/12 by Mr Whippy]

never mind the belts, check the air bags (and any other predictable tit jokes you can think of )
personally i'd leave the mounting out the question til you've got you belts and then fit them as per the belt manufacturers instructions.
Willans seem to show theirs as per the cracking picture above,
i'm sure i've seen diagrams showing them mounted further back