Harness mounting

[Pistol Pete]

I am in the process of making up a new rear mounting for the 4 point harnesses in my metro gti track car (a solid bar across the floor between the wheel arches). I know that the harness straps should be at no more that 45 degrees from horizontal, the less the better. Also, the straps should cross behind the seats, but how far apart should the mountings ideally be?

Thanks,

Pete

[JLD]

Hi Pete, fancy seeing you here.

The rear mounting on my metro are on plates welded to the floor around where the back of the rear seat would have been. Mounting points are around 2 feet apart. As for crossing them over, few of the MGmetro cup drivers seem to. Certainly frowned upon in the rock climbing community when using nylon (?) slings as any movement which involves rubbing can cause failure.

[johnw]

Don't know how far away this is from your shoulders, but it's good to keep the belts as short as possible.
Any chance that you can fit a harness bar closer to your seat?

[zefarelly]

I got picked up at Spa last year, less then 15 degrees I thought from horizontal. they used to go down to the floor!

[Pistol Pete]

Hi John (JLD). What a surprise to see you here. Are we going to see you out in your new toy anythime soon? (like silverstone next Thursday which is my current aim)

Originally Posted by johnw

Don't know how far away this is from your shoulders, but it's good to keep the belts as short as possible.
Any chance that you can fit a harness bar closer to your seat?

The bar will be mounted onto the floor across the top of the spare wheel well.

As I understand it the less the angle between the straps and horizontal the better. The original (rear seatbelt) mounts put the harness at possibly more than 45 degrees to horizontal, which is not good for my spine if nothing else.

With the new mount, I can move the hence I wanted to move the mounting further back, the further back the better the angle of the straps will be, I intend to keep it forward of the centre of the rear wheels so it is protected against rear collision.

Me real initial question was in relation to the seat/car width, how far apart should the mountings be (hence I suppose, how far behind my sholders should the straps cross en route to the floor.

Thoughts...

Thanks,
Pete

[JLD]

Originally Posted by Pistol Pete

Hi John (JLD). What a surprise to see you here. Are we going to see you out in your new toy anythime soon? (like silverstone next Thursday which is my current aim)

can't do weekdays unless it's during school holidays. Hope to get the car out sometime soon though.

[phoenix]

There is no MSA or FIA requirement - and no good reason - to have the shoulder straps crossing over behind the seat. In single seaters and many GT cars they mount directly onto the chassis behind the seat at shoulder height, for example. In 3 point designs for saloons the two shoulder straps merge into one and then that is mounted centrally behind the seat.

For a 4 point harness, the distance between the two mountings for the shoulder straps should be the same as the slots in your seat so that the belts run straight through the slots and over your shoulders.

[greenamex2]

I got told by a scrutineer to UNCROSS my straps on my harness. But this was the first person to mention it after five years of racing. Nobody in the ten years after has told me to cross the straps again.

3 point harnesses are either illegal or will be illegal next year for racing.

[Pistol Pete]

Hmmm.... The instructions that came with them said to cross them. I suppose this may only be an issue if you are using mounts that are further apart than your shoulders though.

They are 4 point, but as I currently only use the car for trackdays (plan on starting racing late next year), MSA rules are not too big an issue yet.

Pete

[phoenix]

Originally Posted by Denis Bassom

3 point harnesses are either illegal or will be illegal next year for racing.

I'm sure they are for racing but they are in use in some other forms of motorsport. Really I mentioned them only in discussing crossing belts and mounting points.

[johnw]

The only reason for crossing belts would be if they had long tails - which you really want to avoid. Your body will be like a pendulum swinging on them if they are long and have a sideways impact.

Can you not mount the harness bar higher (between the roll hoop legs and or cross braces) and closer to your shoulders to reduce the length of the belts? These things stretch alarmingly in a big shunt.

[Pistol Pete]

Looking to the future (racing), I can not mount the harness bar to the cage as then it is not to FIA spec. I have never seen a metro, or other small car with a harness bar welded in seperate from the cage above floor level.

Pete

[MGDavid]

I've definitely seen an MG Midget with a harness mount bar welded between the rear wheel arches. Suppose it acts a bit like a strut brace too - never thought of that before ;-)
I've raced in two different cars this year with a 4 strap harness where the shoulder straps are merged onto the same mount - not failed scrutineering yet !

[Chris Y]

Take a good look at a 2005-spec Mighty Mini - they have a special Safety Devices harness bar, which clamps on (I think) to the main hoop, and is braced on the car's centre tunnel.

[RushyRacer]

Chris the bar in the MM does clamp to the diagonal legs that go to the rear arches and was introduced to alter the angle of the belts to the drivers shoulders but the belts still use the original rear bulkhead base mounts. Also the issue with this bar , fourtunately yet to be tested, is that because it only clamps to the main cage and the regs do not allow it to be welded, it could under heavy loadings, slide up the diagonals even though it is bolted to the transmission tunnel.