Roll Bar tips

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Jimmynb
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Roll Bar tips

Postby Jimmynb » Mon Mar 16, 2015 10:09 pm

I have been looking for a roll bar for some time now, ideally i want a twin hoop set up as i think it looks more stock and luxury. BUT i was warned not to due to this: Image

This was said to be because they are only bolted on and have no structure to grab that isnt straight. so i was looking at roll cages from brown davis, automotive plus and agi roll bars. If i am to go with a full single hoop bar any suggestions as to which or where else is best?

I stumbled across this (http://store.automotiveplus.com.au/p/85 ... e-box.html) which seems to be structurally sound and connected over a large enough space that it wont collapse in the same way, do you suggest that or the strength of a single hoop?

Thanks guys, i appreciate it, i am kinda scared driving it without a cage. it is intimidating.

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Re: Roll Bar tips

Postby Roadrunner » Mon Mar 16, 2015 10:22 pm

I got the automotive plus twin hoop roll bar.
It is an actual rollbar and I believe at one stage was cams approved.

However if you draw a line from the top of the hoops to the front of the bonnet it cuts right through the middle of your head, so while you won't get completely crushed you'll still be in a world of hurt If you finish the wrong way up...
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Re: Roll Bar tips

Postby Trackphotos » Mon Mar 16, 2015 10:34 pm

The photo you posted is of a car with a style bar, not a roll bar. Structurally they offer no rigidity or safety in the event of a crash, and as you can see potentially make things worse. The Automotive Plus twin hoop roll bar will be sturdy and effective, but as Roadrunner said, it's quite low and will not protect you as effectively as a taller rollbar. Not to mention the gap between the hoops is more than large enough to fit armco in, if you have the misfortune to roll along a fence. For maximum safety you want something strong, and as tall as possible without having to sacrifice your roof.

I have a single diagonal tall boy bar, like this: http://store.automotiveplus.com.au/p/85 ... l-boy.html

But if I were doing it again, I'd get the twin diagonals instead here: http://store.automotiveplus.com.au/p/85 ... l-boy.html Only because the centre is a better place to mount a GoPro, whereas the singe diagonal bar makes it a little more difficult to get it in a spot where you can see reasonably straight without having the rearview mirror blocking it.

Are you going to be tracking it? Because if you are not, you may want to reconsider a rollbar. They put your head quite close to them, and in a factory seat you will move around a lot within your seatbelt if you're in a big crash. In the majority of crashes you might experience on the road, the bar will not protect you and may be just another solid bar for you to hit your head on. Rollovers are very uncommon in MX5s in road accidents, much more likely on a race track. At least get a bucket seat with a tall back if you do decide to get a bar.
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Re: Roll Bar tips

Postby manga_blue » Tue Mar 17, 2015 5:09 pm

Trackphotos wrote:Rollovers are very uncommon in MX5s in road accidents, much more likely on a race track.
I disagree with you there. Road rollovers are pretty common with MX5s. Try a google image search for something like "miata rolled over" and you'll find dozens of them, with some being pretty nasty. I think they roll more easily on the road than on the track. It's all to do with what's on the side of a road that you don't get on a track. On a road they tend to drift off and get tripped by something like a small bank or a culvert or a gutter or a rock. On a track they just mostly slide through dirt and grass and stuff like that until maybe they slam a wall.

Rollbars also help prevent 4WDs from riding up the back or side of the car into the cabin. A few of our forum members have had their lives saved by that.
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Re: Roll Bar tips

Postby Trackphotos » Tue Mar 17, 2015 5:51 pm

manga_blue wrote:
Trackphotos wrote:Rollovers are very uncommon in MX5s in road accidents, much more likely on a race track.
I disagree with you there. Road rollovers are pretty common with MX5s. Try a google image search for something like "miata rolled over" and you'll find dozens of them, with some being pretty nasty. I think they roll more easily on the road than on the track. It's all to do with what's on the side of a road that you don't get on a track. On a road they tend to drift off and get tripped by something like a small bank or a culvert or a gutter or a rock. On a track they just mostly slide through dirt and grass and stuff like that until maybe they slam a wall.

Rollbars also help prevent 4WDs from riding up the back or side of the car into the cabin. A few of our forum members have had their lives saved by that.


Granted it's US-based, but the NHTSA (National Highway Traffic Safety Administration) says otherwise. Saying road rollovers are "pretty common" is complete crap. In single-vehicle accidents, Miatas only have a 7% chance of rolling, they are rated among the lowest risk, alongside S2000s, RX8s and Z4s. Of course you'll find photos of rolled ones, that's the magic of the internet, and of searching for crash photos of a car that has a million units. That tells you absolutely nothing. As for rolling more easily on the road than on the track, that's very, very unlikely. On the road you are doing road speeds. On the track you are doing track speeds. If you leave the road you might hit a ditch. If you run wide on a ripple strip, you WILL hit a ditch, and it takes a much smaller one to roll you over if you're going a lot faster. Not to mention the increased likelihood of wheel-to-wheel contact with track traffic, and the fact that ripple strips will get you airborne if you go over them sideways, digging your leading 2 wheels into the ground.

The only road situation in which an MX5 rollover could be considered likely would be coming off a mountain road, where the rollover risk would be massive regardless of what car you were in. The MX5s centre of gravity is so low that it takes an incredible amount of energy to tip it over, unless it's got a huge amount of leverage from digging in somewhere. The faster you're going when it digs in, the shallower the angle it can hit at and still roll.

I didn't say that a rollbar can't save you on the road. I said that in most accidents, it can make it worse for you. You have an extremely low risk of rolling an mx5 on the road, so the safety you gain in that very unlikely situation, is traded for increased chance of massive head injury in every other crash you might be involved in. That's why I suggested a bucket seat with a tall back.
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Re: Roll Bar tips

Postby Charlie Brown » Tue Mar 17, 2015 7:58 pm

I've been involved in tracking my MX5s for the last 12 years in both Club events, Natmeets and Supersprints here in NSW.
In that time there's been only one MX5 that's ended up on its side in a gravel trap at Oran Park to my knowledge. It was a stock NB.
There's been a number in the wall but that's it. None on the roof.
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Re: Roll Bar tips

Postby Jimmynb » Tue Mar 17, 2015 9:54 pm

Thankyou all for the advice, i am looking at a whole bunch, but the style hoops and twin hoops bar are now out for me. So it is a full roll cage i am looking for. I am looking at a whole bunch, Agi, Automotive plus, Brown Davis, DST garage, And if i were to get one i would want it fully professionally padded and I am looking for bucket seats at the moment.

How much do you think the padding would protect me?

and in your opinion what are some decent, bucket seats for a cheap price without being dodgy?

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Re: Roll Bar tips

Postby sailaholic » Tue Mar 17, 2015 10:16 pm

Padding only helps your head if your head can hit the bar.

I have an automotive plus bar and my heads along way from the bar.

Cheap buckets. - sparco sprint V. Can get them a touch under 400 each.

Mx5s are very hard to find seats that fit well due to the small cabin size.

Sprint Vs fit easy, are cheap and are ok comfort wise. I find mine more comfortable then stock for my back but less comfortable for my legs.


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Re: Roll Bar tips

Postby Trackphotos » Tue Mar 17, 2015 11:05 pm

Second everything Sailaholic said. Automotive Plus make good stuff, and have as much clearance as possible without having to lose your roof. Padding for cages is really designed to cushion a helmet, not a head, so it's very hard on it's own. Also if you pad the outer hoop at the top, your roof won't fit. You could do halfbar padding at the top and full padding everywhere else, and it should fit. Seats, Sprint V is the way to go if you find them comfortable. I've done a few 4-5 hour drives in mine and find it more comfortable than stock, but other people find they cause lower back pain. It would be best to find someone with one fitted locally and see if you can try it out, it won't tell you if there's going to be issues on long drives but can at least tell you if its comfortable in general or not. You can mount them on stock rails with minor modification, so you can still slide it forward and back. There are a handful of other seats that fit in MX5s without modification, but you won't find any cheaper than a Sprint V. Bride Lowmax fit, as do Cobra Monaco seats.
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Re: Roll Bar tips

Postby Guran » Wed Mar 18, 2015 7:39 am

If your plan is to do track days or supersprints AND there is any chance of your head coming near the rollbar (in the opinion of the scrutineers), you need to pad it with SFI 45:1 or FIA roll cage padding. This is deemed by CAMS to provide sufficient head protection when wearing a helmet. If the car is then for road use, you will also need soft padding cover in conjunction with the roll cage padding which is quite hard and designed for helmet impacts. Good luck fitting this stuff and having an operational softtop.

http://www.revolutionracegear.com.au/in ... PCID=18358

My Brown Davis rollbar is not padded but I'm quite short and my head is some distance from the rollbar. I've never had concerns raised by scrutineers.
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Re: Roll Bar tips

Postby sailaholic » Wed Mar 18, 2015 8:25 am

I've never had the cams scrutineers worry about my twin hoop being unpadded either.


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Re: Roll Bar tips

Postby Jimmynb » Wed Mar 18, 2015 9:23 am

How common is it to be defected in NSW for having Aftermarket seats and a roll bar? Is that something i have to really worry about?

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Re: Roll Bar tips

Postby Jeo » Wed Mar 18, 2015 9:43 am

It happens. Wouldn't say frequently though.

Also make sure you sit in a Sprint V before following the herd on this one. I really don't get the obsession as they are way to small for my shoulders, and my shoulders aren't exactly massive (says the guy typing this while wearing an X-S business shirt).

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Re: Roll Bar tips

Postby sailaholic » Wed Mar 18, 2015 11:47 am

I agree Jeo they are tight in the shoulders but they fit in the car and have ADR compliance.

I personally much preferred the sparco Evo but wasn't confident I could make it fit without using grinders and hammers.


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Re: Roll Bar tips

Postby Guran » Wed Mar 18, 2015 10:11 pm

Using a race seat in a daily driver seems a bit silly to me. You're exposing yourself to increased chance of being defected (if it's not ADR approved and not engineered), they're not as comfortable, and they're awkward getting in/out of the car. If your MX-5s is your daily drive, you're better off using the normal seat every day and swapping in the race seat when you want to drive to the track. Takes less than half an hour to swap them over.
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