Roll cage required with harnesses ?

[RobPhoboS]

Hopefully this won't turn into some ridiculous heated debate but from my limited understanding, you aren't meant to use harnesses unless there is some kind of roll cage fitted.

(not to confuse harness bar with roll cage)

The theory (I guess in testing too?) is that if you are using a harness (without the cage) and the car rolls, there isn't enough structural integrity (usually) in the roof/pillars, so you end up being that support via your head\neck\back.

 

I've already contacted Schroth to see what they offer for us 2 seaters, as they have some nice products for cars that have back seats, and want to use a harness without all of the extra stuff required.

I'm hoping that they say a harness bar + their 4 point ASM belts will be fine.

 

Although since enough people here also have buckets, harnesses etc I thought it was worth asking too

[Ekona]

You can 100% use harnesses without a cage, given that Elises and Caterhams manage it quite easily

 

There is plenty of structural integrity in the roof and especially A-pillars, as that's exactly what they're designed for from the factory. In 6-pt harnesses you're far less likely to move out of the seat in a rollover situation, unlike with regular seat belts, so you're much less likely to have a head/roof/ground contact scenario. Not sure where you've read that matey, but it's nonsense. If the car rolls and there's enough energy to collapse the roof and A-pillars to the point where your head is going to make contact, it doesn't really matter if you're in harnesses or belts: You're not likely to walk away regardless.

 

With a full cage, you should not be driving it if you're not wearing a helmet. This is because if you have an accident, the bars are that much closer to your head and it makes head/metal contact far more likely. Most people don't give a toss and drive anyway as the car is less likely to deform in a crash (which is of course true), and as long as the cage is designed in such a way that your head isn't within about 6 inches from a bar then I don't think I'd worry about it either. Most OEM cages (GT3 etc) is designed to be well clear of the head area for this reason.

 

This is why harness bars are the best thing for road use: They usually mount to the structural seatbelt mounting points anyway so you keep the strength, and they stay well out of the way of heads. Our Impreza has a harness bar fitted (bolts to all four seatbelt points which is handy), and I used to have a two-piece one in the VXR and a large rollover protection bar in the MX5. The MR2 comes with a bar to use as part of the softtop mechanism, which is handy.

 

4-pt harness is good, but you really must be aware of submarining and they MUST be done up proper tight, like can't breathe tight. If you can wiggle enough to reach the stereo, then they're too loose. 6pt is much much better, although the tightness rules still apply.

[RobPhoboS]

Cheers for the advice

It would more likely be a 4 point roll cage (so the hoop is behind the seats) rather than an out and out full cage IF I ever did go that route.

A friend was with her brother, driving their dads GT3RS which had a full cage, terrible weather conditions and a collision happened, he was in a coma for about 4 weeks as his head hit the bar by the windscreen !

(I'm guessing he was using the normal seat belts)

 

 

I would either go with 4 point ASM, or 6 point, and obviously use the belt as normal (maybe with an extender so it fits properly).

I'll post up what Schroth advise as well.

[Ekona]

Why would the stock belt not fit properly?

 

As long as all the metal is behind the seats, I'd have no hesitation in using it on the road at all. StevoD has a cracking harness bar in his, I wouldn't hesitate to use that above anything else: It really is a good piece of kit

[RobPhoboS]

So it's done like this:

 

And the other side with the red\female buckle bit goes through the side of the seat, thus potentially requiring an extender.

 

Not like this:

 

The belt is useless like that.

Hopefully that kind of illustrates what I meant.

Edited April 19, 2017 by RobPhoboS

[Richf]

Cheers for the advice

It would more likely be a 4 point roll cage (so the hoop is behind the seats) rather than an out and out full cage IF I ever did go that route.

A friend was with her brother, driving their dads GT3RS which had a full cage, terrible weather conditions and a collision happened, he was in a coma for about 4 weeks as his head hit the bar by the windscreen !

(I'm guessing he was using the normal seat belts)

 

 

I would either go with 4 point ASM, or 6 point, and obviously use the belt as normal (maybe with an extender so it fits properly).

I'll post up what Schroth advise as well.

 

I heard of a guy who had a full cage and harnesses in his Evo, got t boned at a junction at low speed but his head hit the roll cage causing catastrophic brain injury. If i had a roll cage I would wear a helmet , but roll cages and harnesses are generally a pain for road cars imo

 

I had a harness bar and harnesses in my Evo and they were a real nuisance on the road but agree with Ekona , have a bad enough accident to roll over and cant see you getting any more injured with harnesses than without (As long as they are fitted correctly, most arent! )

[Paddy78]

There is plenty of structural integrity in the roof and especially A-pillars, as that's exactly what they're designed for from the factory. In 6-pt harnesses you're far less likely to move out of the seat in a rollover situation, unlike with regular seat belts, so you're much less likely to have a head/roof/ground contact scenario. Not sure where you've read that matey, but it's nonsense. If the car rolls and there's enough energy to collapse the roof and A-pillars to the point where your head is going to make contact, it doesn't really matter if you're in harnesses or belts: You're not likely to walk away regardless.

 

I'm not sure I totally agree with this. A normal seat belt would at least offer a slim means of escape, whereas in a harness, you are definitely breaking / crushing your neck if the roof encroaches on your swede... As Dan says though, a roll significant enough to make the roof collapse to that extent is not going to be pretty caged or otherwise. However, a cage has been designed specifically to prevent the roof collapsing and if you think you are going to be doing something where there is a high risk of you rolling... badly, then a cage is the way to go. If you are just tracking it (No motorsport) then you are probably OK with just a harness bar.

 

It's your neck on the line though!

[Ekona]

So it's done like this:

 

Gotcha, shouldn't need an extender though as there should be plenty of slack on the belt plus you fit the buckle to suit. It's how I've got it in my car

[StevoD]

Also use harness on seats designed for them you see so many people using harness on factory seats even the recaros in civics/integras and focus RS have not been built for them. Often the only thing below the styled holes is foam. Unless you want your spine compressed of course

[philw99]

Also use harness on seats designed for them you see so many people using harness on factory seats even the recaros in civics/integras and focus RS have not been built for them. Often the only thing below the styled holes is foam. Unless you want your spine compressed of course

This is the issue I had, ran a harness bar with standard seats for a while but it just wasn't safe.

Much better now with Sparco seats. Haven't got a roll cage yet, might start to investigate costs.

[RobPhoboS]

You probably missed my other thread about seats n rails heh, all of that stuff is cool from my side but I guess useful for anyone looking

[sketch]

I always liked the idea of a caged roadster