Board logo

Harness attachment points - relocating
FFTS - 3/2/10 at 09:49 AM

Just fitting some 6 point harnesses to replace the 4 pointers. The existing side fixings are set at the side and tunnel near to the bulkhead rear so the belts have to come forward outside the seat before routing through the gaps in the GRP seat. This would mean with the new harness the adjusters wouldn't be accessible. I need to move the attachment points forward on level with the gaps in the seat so the adjuster come through the gaps..

The question is what fixings and method would anyone suggest. There's a chassis diagonal in the right place on the outside and not sure what's behind the tunnel cover opposite.


deezee - 3/2/10 at 09:59 AM

Assuming your not moving the belt / side fixings outside of their acceptable mounting angle! Can't you just weld new tabs onto the chassis rails?


MikeR - 3/2/10 at 10:01 AM

The standard approach is weld in new mountings.


I'm curious if there is any other way - random thought is perhaps a steel strip 6" long, one end bolted into the existing mounting and your harness screwed into the other end?

(note i'm not suggesting this is a good idea, just a random idea i've had)


FFTS - 3/2/10 at 10:17 AM

The angle would be exactly online with the gaps in the seat (not forward of this. Would a backing plate with nut welded to one side of the diagonal on the chassis be ok?

It would be stronger welded over the centre of the diagonal but the would mean drilling a hole behind it to accommodate the eyebolt stem. What's the guides for drilling into the chassis?

On the extension idea.. would a short piece of heavy chain from the rear fixings be acceptable and safe?


Richard Quinn - 3/2/10 at 11:12 AM

Not sure if this is entirely relevant or not but, crutch straps should travel in the shortest, most direct route when using fibreglass seats. I have seen several fibreglass seats virtually cut in half by crutch straps pulling through the base of them like a cheese wire in a crash!


FFTS - 3/2/10 at 11:39 AM

Not sure on the fixing for the crutch straps yet. Maybe on the front two floor seat fixing bolts. If too far back I may have to look at cutting slots into the seat for them to come through.

Any other suggestions for the side fixings?


MikeR - 3/2/10 at 11:48 AM

quote:
Originally posted by FFTS
On the extension idea.. would a short piece of heavy chain from the rear fixings be acceptable and safe?


Personally i'd still prefer a 3 or 5mm steel strip 1.5 to 2" wide instead of a chain. Its far in excess of the chassis rail. If you're getting chain you'll need to get certified chain (not cheap) & you'd need some maths to get it rated at the right level.


deezee - 3/2/10 at 11:59 AM

It seems counter productive to have a race car spec 6 point harness, only to botch the mounting points If it can't be fitted as instructions, your better off not fitting it. Oh and yes, you crotch straps need to go through the seat, not over the front edge.



FFTS - 3/2/10 at 12:25 PM

Thanks for that, very useful info. The reasons for the change of harnesses are:

I want to take my 5 yr old girlie out and find a narrow booster seat that will fit in so the harness needs to have a crutch fixing to stop her or the seat sub-marining.

Also I find that I tighten my 4 point and before long it seems slacker around the waist and so gets tightened up on the shoulders while driving. It can end up more like a chest belt rather than a waist belt.

Thanks for the illustration.

[Edited on 3/2/10 by FFTS]


BenB - 3/2/10 at 12:26 PM

I made some extension pieces out of 5mm metal. Bolt at both end, ain't going nowhere in a hurry. I drilled the mounting holes well away from the edges, made sure the whole thing was able to swivel and job's a good'un.

As I see it, my body will rip apart under the deceleration well before 5mm plate will! Obviously just make sure the plate doesn't rust! The main problem as far I'm aware with harnesses is when people put them through shitty GRP seats and then mount them low down (like on most of the chav Corsas). Big impact, harness pulls through the seat and then as the person continues on their merry journey towards the windscreen the harness continues to pull down, compresses the persons spine and it's hello Mr Wheelchair.


BenB - 3/2/10 at 12:30 PM

quote:
Originally posted by FFTS
Thanks for that, very useful info. The reasons for the change of harnesses are:

I want to take my 5 yr old girlie out and find a narrow booster seat that will fit in so the harness needs to have a crutch fixing to stop her or the seat sub-marining.

Also I find that I tighten my 4 point and before long it seems slacker around the wait and get tightened up on the shoulders while driving. It can end up more like a chest belt rather than a waist belt.

Thanks for the illustration.


Then you definately want to sort that out. A chest belt is seriously bad mojo. Loads of injuries in children were caused by poorly adjsuted child belts ending up round the occupants nipples Simon Cowell stylee (for legal purposes I would like to state that I am not suggesting that Simon Cowell has ever had any involvement with childrens nipples ). I use a 6 point and for a quick blat just use it like a 4 but for a spirited drive or long journey put the crutch straps on. Not only stops the harness riding up but also stops submarining under deceleration (especially the rapid variety).