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How to fit Harness


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Guest mrodbert

John,

 

We have a roll bar fitted inside the Surrey top and fixed to the chassis. It's a single rollover and two back stays one, as described in the blue book. Neil Revington do a good one that doesn't impede visibility too much. We then attach a 4 point harness to the roll bar and chassis. However, we do have old style "historic" rally bucket seats that do hold you firmer than the originals.

 

Hope this helps,

Mark

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John

 

One of the key things is to make sure that the belts do not 'push' down on the shoulders of the occupant when they are used - if so you get spinal crush injuries (which are common in low sports cars for this reason).

 

You need to make sure that the belt angle is very shallow - mounting them on the floor on the 'parcel shelf' is not a good idea unless you can loop them round the rollover bar diagonal / horizontal or a specific mounting point.

 

I have a cage in my TR4, belts bolted into the shelf, but 'diverted' around the horizontal so that they 'pull' almost horizontally off my shoulders. This works well.

 

On my 4a I have them on the parcel shelf and honestly its a job I need to do to change them around - they are not right.

 

You could also use a 3 point fixing (i.e. only one rearwards strap) but you may find these uncomfortable in use as i did as im tall.

 

Regards

 

Tony

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Id call it ba no way - you can mount a horizontal bar between the wheelarches to do the job ok - maybe this is worth a try. This is what I will do on my TR4a.

 

Regards

 

Tony

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The roll over bar on my 3a was built with a horizontal bar between the sides, just below the top of the body, so that the harnesses can attach to this rather than the rear shelf, which would be too low.

 

I also use bucket style seats with these 4 point harnesses.

 

This has got around this potentially dangerous problem of spinal injuries.

 

If I were you, I would have a look at cars at the International, assuming you are attending. You will see a variety of different mounting methods. You can talk to owners, the professionals and see the different installations. My car will certainly be there in the concours hall.

 

Regards

 

David

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Guest mrodbert

John

 

Tony's right (as per usual  :angry: ) the parcel shelf is a bad idea. We have the shoulder straps attached to mounting points that are an integral part of the rollbar uprights and cross member, rather than the looped over a horizontal bar as I've seen some on other cars. We got the whole set up done by TRGB when we bought the car.

 

Just an additional point - In my opinion having a rollbar without a decent 4 point harness and seat just creates an additional heavy metal object to put a crease in your cranium if the worst happens. I know some people think you shouldnt have a bar if you're not wearing a helmet, but I'd rather have something than nothing in the event of a "moment".

 

Regards,

Mark

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Both Ade and I have the twin roll hoop arrangement as these have integral mounting points for harnesses built-in in just the right position. Also gives you something to mount an extinguisher on. Can't remember where we got them from though ... TRGB maybe?
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Till now, in my TR3 the 3 point harnesses (4 point harness is not allowed acc. Belgian FIVA rules) are bolted (eyes, plate and nut) in the front attachement points of the fuel tank retaining strap. That is too low and not in the centre of the seat, I agree (but works fine anyway). Having a rollover bar installed recently (Safety Devices via RTR) I intend to install an add. horizontal cross bar with attachements. What size (diam, wall thickness) should be this horizontal bar? Cheers, Rudi
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Before fitting the harness in my car, I've asked around amongst racers : from the shoulders backwards, the shoulder straps should not be sloping upwards, but horizontal or preferably  downwards. Maybe this puts strain on the spine in case of an accident, but it helps preventing the body sliding sidewards out of the harness and forces the body firmly in the seat. An horizontal bar between the top or middle of the inner wheelarches is about right, perhaps the parcel shelf is  a bit too low indeed.

If you want to make a TR real safe, you need a roll cage, a 4 or 5 point harness fixed on the chassis (lower straps) and the roll cage (shoulder straps), and a strong bucket seat that is attached to the chassis, not merely to the floor.

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