Roll Bars ?
Author
Discussion

J4CKO

Original Poster:

45,941 posts

223 months

Monday 2nd January 2012
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Am about now in a position to look for an MX5, quite fancy tracking it at some point and was wondering about the roll bars, how they work with the hood, the downsides and the safety as I read somewhere that if sideswiped it is easy to hit your head on it, very hard and possibly be worse of than one not being there, is this the case as really I dont want to wear a helmet all the time biggrin


bstw

153 posts

207 months

Monday 2nd January 2012
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The most common options are one of TR lane bars or a hard dog which I think you have to order from the states.

I have a Mazdaspeed one which bolts to the seat belt towers and rear shelf, I think my seats as far back as it goes and i don't think there's any chance of hitting my head on the bar.

They all fit fine under the hood/hardtop

Daaave

223 posts

223 months

Monday 2nd January 2012
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No need to worry about hitting your head on a standard roll bar. If you were quite tall, had a full cage and the standard plump seat then maybe you might have to worry about your head hitting the section that runs parallel to the window. But saying as you won't be getting a full cage (permanent removal of the hood), you'll be fine.

m4thew

32 posts

171 months

Monday 2nd January 2012
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I had a Hard Dog fitted to mine. Wasnt obstructive at all.
I dont know about other bars but the Hard Dog bars do not fit every mx5. Some will only fit hoods that have a plastic rear screen.

I took mine off an ebayed it, which resulted in a bidding frenzy! not sure how much one would be to import new but my second hand one went for £290! Frome what i could gather when taking it off was that i would have hated to be the one fitting it, it looked like a right ball ache to fit.


GC8

19,910 posts

213 months

Wednesday 4th January 2012
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T.R.Lane for me.

J4CKO

Original Poster:

45,941 posts

223 months

Wednesday 4th January 2012
quotequote all
Anyone actually turned a 5 over or know of anyone who has, how likely is that on the road ?

MX-5 Lazza

7,954 posts

242 months

Wednesday 4th January 2012
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That's a subject that comes up time and time again. Yes MX5s can and do roll. They aren't as easy to roll as many other cars on open roads due to the lower centre of gravity but they are just as likely to turn over as any other car in a collision with other cars/obstacles. Same applies on track. That's not to say they are prone to rolling or that it should be a major concern for a road or track day car. A full track car would of course have to have at least a roll hoop.

Roll bars should help in a roll over but there are no guarantees. People sometimes die in saloon cars when they roll over after all.

In any collision, if you have roll bars there is a chance that your head can come into contact with the roll bars. Rear-end or side collisions are the worst. Adding padding can help but again this isn't a fix. Would you want me to swing a heady metal bar with a bit of sponge padding on it at your head?

So in summary:
Do you need roll bars? For a full track car yes, otherwise no.
Do they help in a roll over? Probably.
Are they dangerous for your head in a collision? Possibly.
Can you get away without fitting one? Probably.

Mazda didn't fit roll bars as standard to any MX5 from 1989 to 2005.
Mazda do fit standard roll hoops on MX5s from 2005 onwards.
Make of that what you will.

GC8

19,910 posts

213 months

Wednesday 4th January 2012
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J4CKO said:
Anyone actually turned a 5 over or know of anyone who has, how likely is that on the road ?
Do you remember the MX-5 crash at the trackday at an MOD tank proving ground? Most of the pictures have been removed now, but you can still find a few if you spend a while searching. On that car, in that circumstance, it was the safety equipment that saved the driver, without a doubt.

Of course: on another day, in another circumstance you might hit your head on it (the front section) and suffer an injury in an oherwise minor shunt - theres always an element of risk.

Id like a Tim Lane full (bit not MSA approved) cage, but being quite tall Im concerned thatd it might kill me before it saves me. Im making do with a roll bar and lower seats (if youre tall then ask about a 'foamectomy' on Nutz) as I think that the side protection that a front section adds doesnt warrant the extra risk for me.

Eiffel

17 posts

192 months

Wednesday 4th January 2012
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In the US, some of the Hard Dog roll bars, such as my HD Hard Core Dual Diagonal are homologated for some types of competition (Solo I, IIRC). This means that they offer some protection. Such roll bar is also mandatory for most serious trackday

What I consider dangerous are the 'mouse trap roll bars' which are cosmetic and can trap you in the car.

Regarding padding to reduce head impact, standard pipe foam doesn't quite work (it its too soft to protect from any real impact). special SFI foam inserts do offer some protection against big impacts (but are almost as hard as wood) and are also much hard to set on fire...

MX-5 Lazza

7,954 posts

242 months

Wednesday 4th January 2012
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Roll bars aren't mandatory at any track in the UK for track days that I'm aware of.

People are always going on about how dangerous "style bars" (cosmetic hoops that offer no roll protection) are but I've never seen any evidence of this whereas I have seen evidence that at least one has saved someone in a roll as it held up until the car settled on the roof. That was a barrel roll I believe.

trackerjack

649 posts

207 months

Thursday 5th January 2012
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I personally find a roll bar on an ordinary road car something which is more likely to injure you than no bar at all (however check out a standard Stag to see how it should be done IMHO).
All to easy to smash your head on a bar when in collision.
Some insurance companies will not insure a car with one fitted.
On the flip side to that is my Quantum 2+2 RST which has one as standard and I am not thinking of removing it.
While competing in a sprint event at Goodwood I saw an RS2000 barrel roll and it certainly destroyed the car and the damage was frightening as the roof closely followed the contours of the bar.
Oh dear none of this helps you on your posting........however the best bar I have seen on an MX5 is a TR Lane one.

GC8

19,910 posts

213 months

Friday 6th January 2012
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Seats, belts and bars are three things that shouldnt be thought about alone.

trackerjack

649 posts

207 months

Friday 6th January 2012
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Sound advice as the seat if correctly chosen will prevent contact with the bar and full harness belts aid this too, however I find full harness belts so annoying for normal road use so in my track Dolly Sprint I have both types of belt fitted.

Baked_bean

1,941 posts

215 months

Saturday 7th January 2012
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From looking at pictures of the tr lane roll bars fitted, i can't see how your head would make contact with the bar? Well not any worse than you would hit your head on a b pillar in a normal car.

Anyone have any more photos of the tr lane ones? im interested as im thinking of buying one in the near future.

GC8

19,910 posts

213 months

Saturday 7th January 2012
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A foamectomy would help to keep you away from the rear hoop. I was talking about the longitudinal tubes which link the rear hoop to the 'front hoop' in my post though, which is harder to avoid and more of a risk to weigh up.

deviant

4,316 posts

233 months

Monday 9th January 2012
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Baked_bean said:
From looking at pictures of the tr lane roll bars fitted, i can't see how your head would make contact with the bar? Well not any worse than you would hit your head on a b pillar in a normal car.

Anyone have any more photos of the tr lane ones? im interested as im thinking of buying one in the near future.
This statement points you in the right direction.

GC8 said:
Seats, belts and bars are three things that shouldnt be thought about alone.
It might look like you cant touch it and you might sit in your car and think you could not possibly touch it but it is impossible to replicate any accident forces or even begin to guess what your body would do in a smash.

Not an MX5 I know but this guy rolled his BMW325 at speed and you can see that in a normal car seat with a normal seatbelt his upper body is out of the seat...you can see now how you could hit your head on the roll bar. Imagine it running just behind the headrest like it does in an MX5.




MX-5 Lazza

7,954 posts

242 months

Monday 9th January 2012
quotequote all
I only see 2 images, not YouTube links wink

Munter

31,330 posts

264 months

Monday 9th January 2012
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I buy the "you can hit your head on it" line with cages that extend forwards of the headrest. But not so much with bars that are fully behind the seats. I'd suggest that in a car with a roof I'm much more likely to hit my head on the door pillar and frame than I am to hit my head on a roll bar behind the headrests.

This is my car on the P5 website


I don't see any survivable situation where my head is in the same location as the bar is.

And has anybody ever heard of anybody hitting their head on a bar rather than a cage?

matts4

2,082 posts

214 months

Monday 9th January 2012
quotequote all
MX-5 Lazza said:
I only see 2 images, not YouTube links wink
6 min 20 secs is where it all seems to happen...
http://www.youtube.com/watch?v=aHOgKOfjqwc

Munter

31,330 posts

264 months

Monday 9th January 2012
quotequote all
matts4 said:
MX-5 Lazza said:
I only see 2 images, not YouTube links wink
6 min 20 secs is where it all seems to happen...
http://www.youtube.com/watch?v=aHOgKOfjqwc
6:30 gives a good shot of the car.



He's done a proper job there.