Roll bar, yay or nay?

[groomi]

GravelBen said:

pbirkett said:

GravelBen said:

Yes from me, I've got one But I'd say no to a full cage if anyone suggests that.

Mine is a 4-point bolt-in job, main hoop mounts to the floor behind rear seats and stays go back to the chassis rails just in front of the rear struts.

It also tightens up the chassis quite noticeably which is nice

Which one do you have?

It only has a small Japanese label on it (which I can't read) but photos I've found of identical looking units were made by Cusco/Safety 21.



It looks quite close to the seats in that photo but I think its just the angle, you'd have to be well out of the seat (or very tall, I'm 5'10) to make contact.

That looks perilously close to the side of the head. Even with a helmet on, I'd be wrapping foam around the side of that bar - without a helmet you're better off without that bar.

[thewildblue]

I fitted a TR lane bar to mine and wouldnt be without it. It tightened up the car nicely and looks good as well. I spend 6 months of the year riding bikes to work so just sitting in a car is a damm sight safer...banging my head on a roll bar....oh well what will be will be.

[300bhp/ton]

GravelBen said:

heebeegeetee said:

...Personally, i'd choose to not have a shunt in the first place...

Don't we all... I believe some folk call them 'accidents', I think this is because they tend to happen unintentionally.

Personally (especially with track use), I find the roll protection and extra chassis stiffening well worth the small risk of flailing my head backwards over the top of the seat and hitting the bar in an accident. at least my head won't go back far enough to break my neck. Though as said before, good buckets (like the OP has) will make this even more unlikely.

Either way, you pays your money and you makes your choice

+1

[The Wookie]

GravelBen said:

Personally (especially with track use), I find the roll protection and extra chassis stiffening well worth the small risk of flailing my head backwards over the top of the seat and hitting the bar in an accident.

You'd be amazed how far your head moves in an accident. In a moderate rear end shunt I would guarantee that your head would find its way to any one of those goal post items. The only way I'd have one in a road car is if the car was particularly top heavy with a flimsy roof (e.g. Land Rover) or the bar was a long way behind me, or I had a bucket seat with a head surround

[300bhp/ton]

The Wookie said:

GravelBen said:

Personally (especially with track use), I find the roll protection and extra chassis stiffening well worth the small risk of flailing my head backwards over the top of the seat and hitting the bar in an accident.

You'd be amazed how far your head moves in an accident. In a moderate rear end shunt I would guarantee that your head would find its way to any one of those goal post items. The only way I'd have one in a road car is if the car was particularly top heavy with a flimsy roof (e.g. Land Rover) or the bar was a long way behind me, or I had a bucket seat with a head surround

I don't follow that. Surely if you are in a bad enough accident to hit your head on the roll hoop. You either weren't strapped in. So no hope would result in just as bad or worse. Or you'd have hit your head on the ground.

Can't really see the logic in not wanting one. Many motorsports require roll hoops or cages but helmets and full harnesses are not always mandatory. Reckon they might have some idea what they are on about.

[900T-R]

300bhp/ton said:

I don't follow that. Surely if you are in a bad enough accident to hit your head on the roll hoop. You either weren't strapped in. So no hope would result in just as bad or worse. Or you'd have hit your head on the ground.

Eh? Have you seen actual footage of offset front or side impacts with the occupants strapped in with an inertia reel belt?

[The Wookie]

300bhp/ton said:

I don't follow that. Surely if you are in a bad enough accident to hit your head on the roll hoop. You either weren't strapped in. So no hope would result in just as bad or worse. Or you'd have hit your head on the ground.

Can't really see the logic in not wanting one. Many motorsports require roll hoops or cages but helmets and full harnesses are not always mandatory. Reckon they might have some idea what they are on about.

Think about the angle of the seat back, think about it being a 3-point belt that might not have locked because it's not forward shunt. If you're hit hard enough, you will surf up the seat back, which will be bent further back from your weight, straight into the bar. Alternatively the headrest will deflect your head to the side.

Look at any rearward crash test without a whiplash protection system and you'll see what I mean. Believe me, I did a lot of work on this on my Auto Eng course.

Those motorsports tend to be low speed activities where a roll-over is likely, a significant impact is unlikely and where the driver's free movement and visibility are more important, like Trialling or Autocross.

[JR]

300bhp/ton said:

Can't really see the logic in not wanting one. Many motorsports require roll hoops or cages but helmets and full harnesses are not always mandatory. Reckon they might have some idea what they are on about.

In addition to what 900t posted I guess that it would be useful to read my first post on this thread.

As for motorsport regs. their roll bars require a min distance above helmets for the bar (150mm) and most of the bars fitted to road cars do not comply with this requirement. The difficulty that most people face is the hood: a properly designed roll bar usually prevents the hood from closing so people install a lower one without realising the safety risks. Note that most off the shelf bars are sold as style bars or hoops.

Not many people use a full harness and helmet for road use without fail hence: convertable cars should have roll cages for track use but not for road use.

[Munter]

Ok ok. These are from the manufacturer of the bars. So hardly likely to publish "Our bars caused serious brain damage to our customer" stories. But one of them is a "hit from behind", caused the car to flip some how and survived. All of them are "goal post" style bars....none are the Deuce I have!...gulp
http://www.bethania-garage.com/testimonials_story....

[The Wookie]

Munter said:

Ok ok. These are from the manufacturer of the bars. So hardly likely to publish "Our bars caused serious brain damage to our customer" stories. But one of them is a "hit from behind", caused the car to flip some how and survived. All of them are "goal post" style bars....none are the Deuce I have!...gulp
http://www.bethania-garage.com/testimonials_story....

If you look closely at the 'saved me in a rearward impact' it looks like a rear three quarter impact that may have caused him to lose control and crash, rather than the bar actually saving him directly.

Of course it's going to be safer in a roll-over, but like I said before, it's what you think is right based on the balance of probability for your own needs. If I regularly hacked an MX5 down a country road, I'd want one, if I just had it to tool around in the sunshine, I wouldn't.

I still stand by that the twin-hoop designs look much safer though, assuming they're as securely mounted as the goalpost items.

[Gibby78]

I know everyone is talking about if it was shunted up the rear you'd hit you're head, but it'd have to be a fair speed shunt to pull you that high out of your seat, in which case there's a pretty good chance of injury anyway, if I was to rollover though ~I'd rather hit my head on some nice smooth comfy piping than tarmac or a kerb, and think of how much stiffer the car would be in a side impact.

When I was going up Stelvio last year I always had a niggling worry about if I roll this I'm squashed

[NiceCupOfTea]

pbirkett said:

Munter said:

For those wondering how strong the MX5 screen is:
http://www.youtube.com/watch?v=vGHzyNJ3-kI

Thats actually quite disturbing

@ JR - thanks for the post... these posts have certainly put me off a bit.

I think if anything, I think I'd go for a strong hoop style bar which I couldn't headbutt or a strong style bar... or perhaps just try not to roll it

Anybody want to buy an NA 1800?

[The Wookie]

NiceCupOfTea said:

pbirkett said:

Munter said:

For those wondering how strong the MX5 screen is:
http://www.youtube.com/watch?v=vGHzyNJ3-kI

Thats actually quite disturbing

@ JR - thanks for the post... these posts have certainly put me off a bit.

I think if anything, I think I'd go for a strong hoop style bar which I couldn't headbutt or a strong style bar... or perhaps just try not to roll it

Anybody want to buy an NA 1800?

Ignoring all the other stuff that's been said, as scary as that looks, it's not actually that bad for a rag top and there's still some survival space. I'll bet there's plenty of hardtop cars of the same era that wouldn't fare much better.

Try that with a 60's rag top and the road will be flat against the scuttle, hence why I actually do have a goal post bar in my MGB, despite the disadvantages.

[RRH]

For a road going MX5 the best solution is a hard dog bar .. http://www.performance5.com/interior_rollbar.asp.

They are a proper roll-over solution, rather than so-called style bars.

Correctly fitted, the hard dog range won't restrict seat movement and your head shouldn't be anywhere near it as they sit quite far back.

An MX5 has little or no protection in the event of a roll. Fitting a proper roll bar will increase the rigidity quite considerably and will also help in the case of a side impact.

Whilst I wouldn't usually advocate the fitting of a cage / bar in any vehicle unless a helmet's going to be worn (all the time) on this occasion I would consider a bar to be sensible safety equipment.

[Ozzie Osmond]

The Wookie said:

If you're a keen driver and like a good hoon down a back road, then I'd say on balance it's worth having.

Sounds fair enough.

The Wookie said:

If you're just a tootler who never gets near the limits, then it's more likely to cause you injury than save you

Well viewers, if you can understand that leap of logic you're doing better than me......

[warped head]

Reason Insurance Co's and the rozzers dont like cages in road cars is very simple.

Tooooo many chav tastic boy racers are sticking 'off the shelf' drill some holes and bolt in jobbies into the likes of corsa's, saxo's etc. these have all the structural integrity of a drinking straw and therefore in the event of a roll over they go smush just as much as the a, b and c pillars.

This then poses a propblem for the 'jaws of life' as the cages often bend in a random manner and sometimes take up the space that the jaws of life would have been put in making it harder for the fireservice to peel apart the can ... i mean car, and get the muppet out.

Buy the sounds of it the roll hoop your after is a good one. If banging your head is a worry get some cage insulation. 5 quid online from demontweeks available in lots of colours.

Whack that round the thing and then you can bounce your bonce of the thing all day long and only come out with a headache and feeling a bit dizzy rather than having your brains falling out of where the back of your head used to be.

From me its a yes but i'd echo the others on here and suggest a welded jobby

[Red Firecracker]

warped head said:

Reason Insurance Co's and the rozzers dont like cages in road cars is very simple.

My insurance company were overjoyed, to the extent of not charging me any extra, when I enquired about and subsequently told them I had, installed a roll bar. They deem it a safety device and were most welcoming of the modification.

[Mr Will]

warped head said:

Reason Insurance Co's and the rozzers dont like cages in road cars is very simple.

Tooooo many chav tastic boy racers are sticking 'off the shelf' drill some holes and bolt in jobbies into the likes of corsa's, saxo's etc. these have all the structural integrity of a drinking straw and therefore in the event of a roll over they go smush just as much as the a, b and c pillars.

This then poses a propblem for the 'jaws of life' as the cages often bend in a random manner and sometimes take up the space that the jaws of life would have been put in making it harder for the fireservice to peel apart the can ... i mean car, and get the muppet out.

Buy the sounds of it the roll hoop your after is a good one. If banging your head is a worry get some cage insulation. 5 quid online from demontweeks available in lots of colours.

Whack that round the thing and then you can bounce your bonce of the thing all day long and only come out with a headache and feeling a bit dizzy rather than having your brains falling out of where the back of your head used to be.

From me its a yes but i'd echo the others on here and suggest a welded jobby

I think the problem is more likely to be the fact that if you are thinking about fitting a roll-cage then it suggests you think that there is a fair chance of you having a crash, which is enough to make most insurers run a mile.

[Mr Will]

Gibby78 said:

I know everyone is talking about if it was shunted up the rear you'd hit you're head, but it'd have to be a fair speed shunt to pull you that high out of your seat

Doesn't have to be a rear end shunt, you could spin it and hit something while travelling backwards.

But you do get thrown around a huge amount in a crash, even with a seatbelt on. What do you think side airbags are for?

[mattviatura]

Track yup

road nope