V8S SEAT HARNESS
Discussion
I am having a roll-bar and seat harnesses fitted in my V8S, I was wondering if anybody had experience of the comfort on long journey's between a 3 point or 4 point fixing. Also does the addition of the roll-bar increase the wind noise with the hood down? I would appreciate any experience of using the harness in an S.
Thanks tivman
Thanks tivman
You will almost certainly need to retain the original seatbelt in order to be road legal. It is possible to reposition the original seat belt spool in front of the legs but I've seen people who didn't bother and ended up without the original seat belt.
It is important to get the bar's geometry right, and also quite difficult. The front legs will need to be right back into the corner of the tub to avoid limiting the position of the seat back. The top of the bar will need to be as far back as possible in order to stay clear of the driver's head and also tight up against the rear hoop so that you can see under it. Even with optimal positioning it will cut off the top half of the rear view mirror. If you're short, you may be able to move the mirror down half an inch - I'm not, and needed to keep the mirror in its original position. Angling the mirror up (so the top half shows the roof) moves the 'point of view' down an inch or so and is a big help.
Although you can use a '3 point' harness, I advise against it because you will struggle to get enough distance between the eye bolt and the seat (see below) so the Y will be very close to your neck - these work a lot better in saloon cars where you have a few feet to play with. Using twin rear straps also means you can get a better angle (closer to parallel with the centerline) and you should be able to get at least one strap parallel.
The rear stay/stays need to be no more than 30 degrees below horizontal, and as close to parallel with the centerline of the car as possible - absolute maximum of 15 degrees side angle. If you plan to do any motorsport you should avoid mounting multiple straps onto one eye bolt which means using a bobbin each side of the rear led rather than a single one on the front - you need to make sure they do this, because it's impossible to fix if they get it wrong. You also need to ensure your that there is enough distance from the eye bolt to your seat to accomodate the adjuster on the harness straps which means the stays have to be right back against the rear of the parcel shelf. The position of the rear stays is crucial - I was not able to get them out far enough to line up with the center of the seat but you can get pretty close. This is tricky because you also have to meet up with the chassis under the parcel shelf.
Ideally have at least one diagonal cross brace across the main hoop but do not plan to attach any traps to it. 'X' bracing looks cool but makes access to the rear parcel shelf difficult.
I was the guinea pig for the first Roll Center bar for the S and spent a few months driving round with foam pipe insulation where the bars was going to fit to see how convenient it was going to be - I suggest you do the same before getting your proposed bar installed. Done right they are not particularly awkward, but I've seen some that look as if they would be an absolute nightmare to live with. Also once you have decided where you plan to put the bar sort out where the harness straps will go, ideally actually buy your proposed harness and get clear in your mind how must space you will need for the clips, webbing joins, adjusters etc. If you haven't looked into these before you may be surprised how much space they take up.
One trick I found very useful is that with care (and a lot of swearing) you can feed the double thickness strap joints through the adjusters which reduces the overall length by several crucial inches.
To secure the lap straps to the car you will need to replace the existing bolts with eye bolts. Although the harness will likely come with eyebolts, they will probably only be 3/4" bolts designed to go through a steel shell and not long enough to give the required thread engagement after they have gone through the fiberglass - you will need to get a pair of 1 1/2" eye bolts.
There is a huge variety of harness releases and should/lap strap adjusters and I suggest you pay for good quality user friendly ones and not those hideous cheap ones which you will be swearing at in a couple of months time. I suggest using at least 3" wide shoulder straps for comfort and a rotary release buckle. Make sure you decide which side the buckle needs to be. On mine the seat leaves relatively little space between the seat and the tunnel and I fitted the buckle on the outside lapstrap by using a passenger side harness on the driiver's side.
It is important to get the bar's geometry right, and also quite difficult. The front legs will need to be right back into the corner of the tub to avoid limiting the position of the seat back. The top of the bar will need to be as far back as possible in order to stay clear of the driver's head and also tight up against the rear hoop so that you can see under it. Even with optimal positioning it will cut off the top half of the rear view mirror. If you're short, you may be able to move the mirror down half an inch - I'm not, and needed to keep the mirror in its original position. Angling the mirror up (so the top half shows the roof) moves the 'point of view' down an inch or so and is a big help.
Although you can use a '3 point' harness, I advise against it because you will struggle to get enough distance between the eye bolt and the seat (see below) so the Y will be very close to your neck - these work a lot better in saloon cars where you have a few feet to play with. Using twin rear straps also means you can get a better angle (closer to parallel with the centerline) and you should be able to get at least one strap parallel.
The rear stay/stays need to be no more than 30 degrees below horizontal, and as close to parallel with the centerline of the car as possible - absolute maximum of 15 degrees side angle. If you plan to do any motorsport you should avoid mounting multiple straps onto one eye bolt which means using a bobbin each side of the rear led rather than a single one on the front - you need to make sure they do this, because it's impossible to fix if they get it wrong. You also need to ensure your that there is enough distance from the eye bolt to your seat to accomodate the adjuster on the harness straps which means the stays have to be right back against the rear of the parcel shelf. The position of the rear stays is crucial - I was not able to get them out far enough to line up with the center of the seat but you can get pretty close. This is tricky because you also have to meet up with the chassis under the parcel shelf.
Ideally have at least one diagonal cross brace across the main hoop but do not plan to attach any traps to it. 'X' bracing looks cool but makes access to the rear parcel shelf difficult.
I was the guinea pig for the first Roll Center bar for the S and spent a few months driving round with foam pipe insulation where the bars was going to fit to see how convenient it was going to be - I suggest you do the same before getting your proposed bar installed. Done right they are not particularly awkward, but I've seen some that look as if they would be an absolute nightmare to live with. Also once you have decided where you plan to put the bar sort out where the harness straps will go, ideally actually buy your proposed harness and get clear in your mind how must space you will need for the clips, webbing joins, adjusters etc. If you haven't looked into these before you may be surprised how much space they take up.
One trick I found very useful is that with care (and a lot of swearing) you can feed the double thickness strap joints through the adjusters which reduces the overall length by several crucial inches.
To secure the lap straps to the car you will need to replace the existing bolts with eye bolts. Although the harness will likely come with eyebolts, they will probably only be 3/4" bolts designed to go through a steel shell and not long enough to give the required thread engagement after they have gone through the fiberglass - you will need to get a pair of 1 1/2" eye bolts.
There is a huge variety of harness releases and should/lap strap adjusters and I suggest you pay for good quality user friendly ones and not those hideous cheap ones which you will be swearing at in a couple of months time. I suggest using at least 3" wide shoulder straps for comfort and a rotary release buckle. Make sure you decide which side the buckle needs to be. On mine the seat leaves relatively little space between the seat and the tunnel and I fitted the buckle on the outside lapstrap by using a passenger side harness on the driiver's side.
magpies said:
The street legal ones all seem to be of the 'Push Button' style that allows one handed operation.
I have a feeling that is actually one of the requirements for type approval. The one I had was definitely made to a price and had the cheap and nasty shoulder strap adjusters too. Well worth paying more for a decent quality one, even if it does mean you are forced to keep the original too. Just about everyone does, in any case.There are several British Standards that apply to seat belts, I'm not at all certain what they say though as I don't have a copy.
The relevant european standard for them is http://eur-lex.europa.eu/legal-content/EN/ALL/?uri...
The important bit being
Construction and use regs says the harnesses need to either comply with BS 3254:1960 or Community Directive 77/541
What sort of harness you want depends on what you're going to use it for. If it's only ever going to be used on the road there's no real reason not to use a road legal one, they're nearly as good as proper ones. If you're going to use it for competition then I'd leave the standard belts in and fit a proper competition harness too.
The relevant european standard for them is http://eur-lex.europa.eu/legal-content/EN/ALL/?uri...
The important bit being
The buckle shall be released by pressing either a button or a similar device. The surface to which this pressure is applied shall have, in the position of actual unlocking:
- for enclosed devices, an area of not less than 4·5 cm2 and a width of not less than 15 mm;
- for non-enclosed devices, an area of not less than 2·5 cm2 and a width of not less than 10 mm.
This area shall be coloured red. No other part of the buckle shall be of this colour.
Construction and use regs says the harnesses need to either comply with BS 3254:1960 or Community Directive 77/541
What sort of harness you want depends on what you're going to use it for. If it's only ever going to be used on the road there's no real reason not to use a road legal one, they're nearly as good as proper ones. If you're going to use it for competition then I'd leave the standard belts in and fit a proper competition harness too.
GreenV8S said:
magpies said:
The street legal ones all seem to be of the 'Push Button' style that allows one handed operation.
I have a feeling that is actually one of the requirements for type approval. The one I had was definitely made to a price and had the cheap and nasty shoulder strap adjusters too. Well worth paying more for a decent quality one, even if it does mean you are forced to keep the original too. Just about everyone does, in any case.IVA testing for kitcars is a pretty good guideline and turn buckle full harness belts are perfectly acceptable.
I've put many through the test and the tester has never even looked at the seat belt label all he is interested in is that the bolts are the right spec. i.e. 8.8 if metric or three bars if imperial or the very low dome head used for seatbelts even though they have no markings. If you use eye bolts then they should be stamped 8.8 so beware that many aftermarket ones are not marked.
Also for IVA if you are using a bolt through a roll bar then the hole must be sleeved and welded both sides. It is not acceptable to weld a nut or threaded boss onto the outside of a tube unless it has additional bracing such as being in the corner of a two tube junction.
Steve
I've put many through the test and the tester has never even looked at the seat belt label all he is interested in is that the bolts are the right spec. i.e. 8.8 if metric or three bars if imperial or the very low dome head used for seatbelts even though they have no markings. If you use eye bolts then they should be stamped 8.8 so beware that many aftermarket ones are not marked.
Also for IVA if you are using a bolt through a roll bar then the hole must be sleeved and welded both sides. It is not acceptable to weld a nut or threaded boss onto the outside of a tube unless it has additional bracing such as being in the corner of a two tube junction.
Steve
Thanks Guys, an awful lot to think about before I finally spec the harness and mounting points. Also interesting that if the roll-bar is not situated correctly it will block the rear view mirror, particularly with the hood up. I think I need to take a look at a few V8S's with roll-bars in order see exactly all the problems particularly the harness mounts. If anybody happens to have any photos that would be greatly appreciated.
Thanks Tivman
Thanks Tivman
Another point from the IVA on seat belts is that the belt must pass over the shoulder and straight to the fixing point meaning it must not pass shoulder, top of seat/hole in seat, mounting point. Reason being that in an accident the seat could 'crush' where the belt passes over it allowing a reduction in belt tension and allowing the person to travel further forwards than would otherwise be the case.
Steve
Steve
Steve_D said:
Another point from the IVA on seat belts is that the belt must pass over the shoulder and straight to the fixing point meaning it must not pass shoulder, top of seat/hole in seat, mounting point. Reason being that in an accident the seat could 'crush' where the belt passes over it allowing a reduction in belt tension and allowing the person to travel further forwards than would otherwise be the case.
Steve
Is it explicit that it must not pass through the seat? As far as i recall the blue book only talks about the strap alignment - it is normal for straps to pass through high backed safety seats.Steve
GreenV8S said:
Steve_D said:
Another point from the IVA on seat belts is that the belt must pass over the shoulder and straight to the fixing point meaning it must not pass shoulder, top of seat/hole in seat, mounting point. Reason being that in an accident the seat could 'crush' where the belt passes over it allowing a reduction in belt tension and allowing the person to travel further forwards than would otherwise be the case.
Steve
Is it explicit that it must not pass through the seat? As far as i recall the blue book only talks about the strap alignment - it is normal for straps to pass through high backed safety seats.Steve
Steve
Depends upon the design of the seat. Some seats have holes for shoulder harnesses others don't but may have the head restraint designed narrow enough for the harnesses to be worn.
Anchorage points are required below the hips and behind the shoulders. If a crutch strap is to be used, the anchorage points need to be below and behind the crutch.
If suitable anchorage points with 7/16” U.N.F. threads are already provided, these should be used in preference to fabricating new points.
Lap and shoulder anchorage points should be capable of withstanding loads of 3500 lbs (1590kg).
Straps should run directly from the lap or centre of shoulder to their anchorage point with no obstruction or deviation. Straps should not be twisted.
The lap straps should hold the lap region over the greatest possible surface area. They should terminate downwards and rearwards of the hip joint - between 30° and 80° of the horizontal - and be positioned symmetrically about the wearer on either side of the seat (see fig A).
LAP STRAPS SHOULD NOT BE WORN OVER THE ABDOMEN.
The shoulder straps must be between 0° (horizontal) and 45° (Fig. A).
Manufacturer’s rear seat belt lap anchorages (found below rear seat cushions) may be used if they satisfy the requirements above, i.e. are positioned behind the relevant front seat and are 12” (300mm) to 20” (500mm) apart.
Strap lengths should be as short as possible for best performance.
Anchorage points are required below the hips and behind the shoulders. If a crutch strap is to be used, the anchorage points need to be below and behind the crutch.
If suitable anchorage points with 7/16” U.N.F. threads are already provided, these should be used in preference to fabricating new points.
Lap and shoulder anchorage points should be capable of withstanding loads of 3500 lbs (1590kg).
Straps should run directly from the lap or centre of shoulder to their anchorage point with no obstruction or deviation. Straps should not be twisted.
The lap straps should hold the lap region over the greatest possible surface area. They should terminate downwards and rearwards of the hip joint - between 30° and 80° of the horizontal - and be positioned symmetrically about the wearer on either side of the seat (see fig A).
LAP STRAPS SHOULD NOT BE WORN OVER THE ABDOMEN.
The shoulder straps must be between 0° (horizontal) and 45° (Fig. A).
Manufacturer’s rear seat belt lap anchorages (found below rear seat cushions) may be used if they satisfy the requirements above, i.e. are positioned behind the relevant front seat and are 12” (300mm) to 20” (500mm) apart.
Strap lengths should be as short as possible for best performance.
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