32 replies to this topic

[Tamworthbay]

MOT worthy doesn't mean legal. The IVA is a much better indication of what is road legal than the MOT because it is actually checking for legality. Any clip in harness will only pass IVA with the clips wired shut.
My apologies for what I said about mounting angles above if it is wrong. It has always been considered safe to mount at up to 45 degrees below the shoulder to my knowledge, I have not seen this publication before and I will have to bear it in mind in future. Of course road vehicles don't generally experience the same sort of accidents that race cars do which is why the rules are different, and we don't use HANS, but there are freak accidents and you should fully consider safety when you change anything from standard. So I guess this means there really is no way to use harnesses and still have the rear seats, because to comply with these mounting instructions in a Mini really demands a harness bar of some form.

The mounting is identical with/ without HANS (although seat design is critical for HANS). All of the main suppliers have similar guidelines for booth FIA and E marked harnesses but the Schroth one is the most comprehensive. The issue with increased angles is the compression of the spine in a severe accident. This would be the same whether on the road or in a race situation, if anything worse on the road as severe frontal impacts are thankfully rare in Motorsport. I have certainly seen a few minis with belts mounted as you suggested and I think it was once considered ok even to use the standard rear seatbelt mounts (thankfully this practice is now frowned upon).

I certainly can't see a safe way to use a harness and retain use of the rear seat. Unless of course you look at detaching the upper straps and using a standard belt on occasions. The angle to the rear shelf is ok but that would require significant structural reinforcement of the mounting area as mounting to the parcel shelf without would be potentially lethal.

[Mk1Dave]

I have certainly seen a few minis with belts mounted as you suggested and I think it was once considered ok even to use the standard rear seatbelt mounts (thankfully this practice is now frowned upon).

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This is interesting. As this was advised as a good place to bolt them too. Last time I fitted a set. Can't remember where I read that though. The angle from the seat was good and was a strong enough mounting. May have to think about moving mine onto a harnes bar.

[Dan]

This seems to be a currently ongoing change in thinking. Having just had a quick look at the various harness manufacturers I know of there are still some suggesting installation at up to 45 degrees below horizontal, in which case the standard rear belt mountings could be fine depending on the fitted position of the front seats as we have seen on here many times. More and more companies however are indeed saying to keep within 20 degrees below horizontal, with one issuing apparently contradictory diagrams showing both 20 degrees below and above horizontal with the shoulder straps almost right behind the driver on the floor in one which is very wrong. This suggests to me that companies are trying to catch up with a change in philosophy and tripping over themselves a little. If this is adopted by ruling bodies there could be a lot of cars failing scrutineering!

Thanks for bringing this up Clive.

[vx220]

I think the rear seatbelt lower points were recommended as they ARE a seatbelt mounting point, so it was assumed they are strong enough? But it's the angle that's the problem. In my FRST we used the UPPER mount for the rear seatbelt to locate a three point harness, so the angle was spot on.

I uave seen this once in a mini, unsure if the C pillar is strong enough for this? I assume it is on later, rear-seatbelt equipped minis?

[Mk1Dave]

I always thought it was 45 degree angle up
From the back of the seat. Obviously got that wrong as well. And bolting them straight to the floor was a big no no.

[Dan]

I think the rear seatbelt lower points were recommended as they ARE a seatbelt mounting point, so it was assumed they are strong enough? But it's the angle that's the problem. In my FRST we used the UPPER mount for the rear seatbelt to locate a three point harness, so the angle was spot on.
I uave seen this once in a mini, unsure if the C pillar is strong enough for this? I assume it is on later, rear-seatbelt equipped minis?

The mounting points that exist as standard are absolutely strong enough, even if you use an FIA rather than E or BS harness which will hit the mountings harder (the 3" thick webbing does not stretch, the 2" thin webbing does). But the rear shoulder point was never good for mounting a 3 point harness as it's way too far off to the side. It would be fine for one point of a 4 point but you would need a bar or something for the other shoulder.

[Dan]

I always thought it was 45 degree angle up
From the back of the seat. Obviously got that wrong as well. And bolting them straight to the floor was a big no no.

45 up is the same as 45 down, 45 degrees is half way!

[Gremlin]

I think the rear seatbelt lower points were recommended as they ARE a seatbelt mounting point, so it was assumed they are strong enough? But it's the angle that's the problem. In my FRST we used the UPPER mount for the rear seatbelt to locate a three point harness, so the angle was spot on.
I uave seen this once in a mini, unsure if the C pillar is strong enough for this? I assume it is on later, rear-seatbelt equipped minis?

The mounting points that exist as standard are absolutely strong enough, even if you use an FIA rather than E or BS harness which will hit the mountings harder (the 3" thick webbing does not stretch, the 2" thin webbing does). But the rear shoulder point was never good for mounting a 3 point harness as it's way too far off to the side. It would be fine for one point of a 4 point but you would need a bar or something for the other shoulder.

You could bolt a harness bar between the 2 holes and bolt it through into rivnuts in various other places for added strength

[Mk1Dave]

I always thought it was 45 degree angle up
From the back of the seat. Obviously got that wrong as well. And bolting them straight to the floor was a big no no.

45 up is the same as 45 down, 45 degrees is half way!

Haha. Yeah I realised this after I posted. I really shouldn't interact with people before engaging my brain. And having that first cup of coffee.

[Bungle]

 

I always thought it was 45 degree angle up
From the back of the seat. Obviously got that wrong as well. And bolting them straight to the floor was a big no no.

45 up is the same as 45 down, 45 degrees is half way!

 

 

 

you've not worked with Cornish builders

[Cooperman]

The entire issue with full harness belts is a very 'grey' area.

For example, the current regulations seem to state that the belts must be push-button release, but for motor sport, including rallying which requires the cars to be used on the road, the buckles must be aircraft-type twist release type.

MSA/FIA regulations allow for the shoulder straps to be mounted to either two separate lugs, or one single lug mounted centrally, and this can be at the base of the rear panel with reinforcing plates in the boot welded in place. That's what my 'S' has and I've never had any scrutineering problems. When I rolled the car and went down a 15 ft drop they worked fine as well.

The only issue is that the rear seats are not useable and it's a real 'pain' to have to change the belts to carry rear seat passengers.

Really one might consider full harness belts as competition use only in the same way as roll cages are best used only in competition cars.

I've not had an MoT issue with my FIA belts with twist buckles, but my tester also used to use Minis in competition. Anyway, a 1964 car doesn't actually need any seat belts, so if it was an issue I would simply remove them for MoT.

[Mk1Dave]

I've got twist type in mine and also never had issues when it comes to mot

[GraemeC]

The guidance in Clive's link is interesting but as you say Dan, it is their guidance, other manufacturers are quoting other angles.

I guess ideally you need to fit to conform with the guidance of your particular belt's manufacturer - interestingly I bet Safety Device's harness bar, as designed for the Miglias, doesn't achieve the guidance in that publication.

[Sleepy Stu]

The guidance in Clive's link is interesting but as you say Dan, it is their guidance, other manufacturers are quoting other angles.

I guess ideally you need to fit to conform with the guidance of your particular belt's manufacturer - interestingly I bet Safety Device's harness bar, as designed for the Miglias, doesn't achieve the guidance in that publication.

 

Correct different manufactures seem to put forward different angles.

 

For example there is this diagram that would suggest (although not ideal) that the rear seat belt mounts can be used

 

[Tamworthbay]

The guidance in Clive's link is interesting but as you say Dan, it is their guidance, other manufacturers are quoting other angles.
I guess ideally you need to fit to conform with the guidance of your particular belt's manufacturer - interestingly I bet Safety Device's harness bar, as designed for the Miglias, doesn't achieve the guidance in that publication.

 
Correct different manufactures seem to put forward different angles.
 
For example there is this diagram that would suggest (although not ideal) that the rear seat belt mounts can be used
 

I could be wrong, but I am fairly sure that is an old FIA diagram, the current one (which I will try and drag up when I am back in work Monday) removes the acceptable angles. I think this has been the driving force (forgive the pun) behind changes to all the main manufacturers. At the end of the day, motor vehicle safety is an ever evolving area and what was considered good practice one day is deemed unsafe the next. I understand the reasons behind the change to be the possibility of spinal crush injuries in frontal accidents when belts are mounted at high angles (e.g 45 degrees from the horizontal - should that be a low angle?). If you imagine the movements of the belt in a crash. If the belt is horizontal then a body moving forwards against it will not exert a turning motion and and the angle will remain more or less the same. If the angle is steep then that forward motion will cause the angle to become shallower, potentially crushing the occupant of the seat. I think we are only talking about very high energy crashes (in which a mini driver may not survive anyway) but for a new installation it pays to be as safe as possible.