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NA rollbar

Posted: Tue Aug 31, 2010 11:24 am
by adelaide paul
I am interested in buying a rollbar for my NA and want one that will provide protection in the case of a rollover while being comestically appealing and fitting within the soft top
The twin hoop chrome ones look neat but I don't know how good they are
I also understand that some also provide additional body bracing
What are your thoughts?

NA rollbar

Posted: Tue Aug 31, 2010 11:41 am
by Dweezle
You really only have a couple to choose from.

Brown Davis bar fits under both soft and hard top. Is Cams certified if that's something you need and stiffens the car right up.

There is also the mx5 plus Torque bar.
Comes in a twin hoop and a diagonal bar style.

Everyone seems very divided on here regarding these 2 bars.

A quick search will show you a few heated discussions regarding them.




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Re: NA rollbar

Posted: Tue Aug 31, 2010 3:33 pm
by Mr Morlock
If you are interested in safety buy a later model MX5. I have always doubted whether apart from track cars that roll bars are fitted with safety as the prime factor.

Re: NA rollbar

Posted: Tue Aug 31, 2010 5:08 pm
by adelaide paul
Safety is my primary consideration, I don't want to be buying a style bar for looks only

Re: NA rollbar

Posted: Wed Sep 01, 2010 10:31 pm
by hks_kansei
as Dweezle said, basically 2 options.

Brown Davis (BD) or MX5+

BD is only available as a single hoop.
Image

MX5+ is available as a single hoop (similar to BD above)

and as a twin hoop:
Image



if you absolutely must have twin hoop, then the decision is easy.

If you arent fussed, it gets a bit more complicated.

Re: NA rollbar

Posted: Thu Sep 02, 2010 11:51 am
by Noddycar
Hello all. I am also looking for a roll bar, but want to ensure that it is tall enough to actually offer real protection. I am just over six feet tall, and my head is higher than the rear of the seat. I know they still need to go under the soft top etc, but has anyone got a similar issue and found one roll bar better than the others?

Thanks

Re: NA rollbar

Posted: Thu Sep 02, 2010 12:53 pm
by adelaide paul
I would think that the additional height you require would probably not fit under the soft top

Re: NA rollbar

Posted: Thu Sep 02, 2010 1:05 pm
by Noddycar
Yes, but my head fits comfortably under the soft top..... I can also pull the soft top up and down while I am sitting in the seat, so you would imagine someone might manufacture a rollbar which just clears the top?

If I can't get a rollbar tall enough, I am really wasting my money, as in the unlikely event the car does roll, I will still lose the top of my skull :P

Re: NA rollbar

Posted: Thu Sep 02, 2010 1:25 pm
by Bauer
Noddycar wrote:Yes, but my head fits comfortably under the soft top..... I can also pull the soft top up and down while I am sitting in the seat, so you would imagine someone might manufacture a rollbar which just clears the top?

If I can't get a rollbar tall enough, I am really wasting my money, as in the unlikely event the car does roll, I will still lose the top of my skull :P


My opinion - and it really isnt worth much - is that the height Vs protection thing is really valid if you are wearing a harness but not if you wear a lap/sash belt. A harness will keep you upright in a rollover where a standard belt will allow you to flop to the side.

I looked at this from the other side once where I had a mum and dad want to buy a harness for their son and we discussed a rollover event. Without a bar or cage, would he be worse off in a harness in a rollover sitiation? I believe he would be.

Re: NA rollbar

Posted: Thu Sep 02, 2010 3:18 pm
by Noddycar
Hi Bauer

You could be right, but that would be assuming that the body has not rebounded into an upright position at the exact time the unit turns upside down. It is an assumption that, if wrong, means near certain death :wink: . I would prefer to play it safe and KNOW that there is adequate clearance. Even then, there is no guarantee, but it certainly reduces the risk.

Re: NA rollbar

Posted: Thu Sep 02, 2010 3:47 pm
by Guran
There are a couple of guys doing the NSW Supersprints who're about 6'4" and both have BD rollbars in their cars (Mark Hellmund in an NB8B and Scott McGarry in an NA6). They each have race seats fitted, which gives a lower seat position than the standard seat. Mark also has a CF hardtop which gives a bit more head clearance compared with the stock hardtop, and especially the softtop. Even so, Mark has light wear marks on the top of his helmet where it has rubbed on the roof. In both cases, the rollbar just fits under the roof, which suggests that the top of their helmeted heads is pretty close to the same level as the top of the rollbar.

BTW, anyone who thinks they will be able to control where their head, body and limbs go in the event of a rollover is dreaming. I am in no doubt that an occupant stands a better chance of survival in a rollover if their MX-5 is fitted with a rollbar, regardless of whether they're wearing seatbelt or harness.

Re: NA rollbar

Posted: Thu Sep 02, 2010 5:51 pm
by Mr Morlock
Guran is the statistics man ( and here there are none that I have seen)and it is ok to believe that roll bars are good. But you do hear that road crashes involve collisions which can mean the chance of a head hitting a piece of added plumbing. Some say you wrap the bars but I think this would be next to useless.
The cars are still not fitted with roll bars OE and you would think that if crash statistics proved there was an unacceptable risk then it would have been mandated by Govts or addressed by the car maker.The maker never offered them as optional equipment.
Safety concsious people pick a car based on cash test performance and maybe number of air bags.Some will not buy certain Asian built cars due to dodgy results. Given a choice of a roll bar or an air bag the latter surely is the right selection. Race tracks are a different situation.
Nevertheless we make our choice and it is legal.

Re: NA rollbar

Posted: Thu Sep 02, 2010 6:14 pm
by Guran
Mr Morlock wrote:Guran is the statistics man

Why thank you sir! :mrgreen:

The cars are still not fitted with roll bars OE and you would think that if crash statistics proved there was an unacceptable risk then it would have been mandated by Govts or addressed by the car maker.

True for NAs and NBs, but NCs are standard with twinhoop rollover bars behind the seats. I believe rollover protection in convertibles is now an ADR requirement for new cars. There are also ADRs applicable to the installation of aftermarket rollover protection systems (ROPS), which regulate the clearance between the bars and head position, so impacts with hard plumbing are avoided. Based on the measurements I've done with my car, the BD rollbar complies.

Safety concsious people pick a car based on cash test performance and maybe number of air bags.Some will not buy certain Asian built cars due to dodgy results. Given a choice of a roll bar or an air bag the latter surely is the right selection. Race tracks are a different situation.
Nevertheless we make our choice and it is legal.

Agreed! Yet there are still plenty of NAs on the road. Would you rather see them all scrapped? I would encourage NA/NB owners who want to give themselves a bit more protection (NAs especially) to give serious consideration to installing a rollbar. It's a small price to pay, and there is also the added benefit of improved chassis stiffness.

Re: NA rollbar

Posted: Thu Sep 02, 2010 7:29 pm
by Mr Morlock
NC roll bars are not classed as a safety feature ie essentially cosmetic- I think many people are unaware of this.

The makers of the aftermarket roll bars I believe cannot show you any data on crash safety in a road condition.

Insofar as MX5's without airbags it is an interesting question. I think it is a calculated risk and for a daily user with high KM's I wonder if it is a wise choice. For a hobby car, like old classics, with low KM usage it is probably not a big issue and many of us would buy one of these great little cars for fun and enjoyment. Road safety experts warn that many younger drivers who cannot afford later model cars should be careful in what they select-data is published to make a choice which might save a life or minimise injuries.

In some other markets the old cars are actively discouraged - Au still has a very old car park with many vehicles lagging behind on safety features.

Re: NA rollbar

Posted: Thu Sep 02, 2010 9:59 pm
by hks_kansei
For the record Morlock, In Victoria it is a requirement that rollbars are padded with proper material to protect against head trauma in a crash.

Motorsports shops sell lengths of this padding that has been tested (I got mine at Meridian Motorsports for $10 per metre)



as my head is above the factory headrests, I would think I'm actually safer with a padded bar, the padding will absorb the impact, and the location will actually prevent my head from being flung back and causing severe neck injuries.