mr henderson
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| posted on 24/12/09 at 02:13 PM |
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How often do cars roll over in accidents?
Thought it was time for another discussion about rollover protection and whether the average hoop and 2 braces was offered enough protection for road
use, or not enough, or was more than was really needed.
However one notes that in some classes of racing full cages are required. Should a road-only user start to worry about this, and feel that maybe he
should have a cage as well?
Just how likely are our cars to end up upside-down anyway?
[Edited on 24/12/09 by mr henderson]
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blakep82
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| posted on 24/12/09 at 02:16 PM |
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well, in 10 years i've never rolled a car 
never had a proper crash either. so probably not very likely, but you know if you decided to go without one it'll happen
i did see a car on its roof on the motorway the other night right enough. did it all itself.
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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graememk
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| posted on 24/12/09 at 02:20 PM |
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as a rule of thumb.
You need to be driving at 40MPH + and hit something while going sideways at low speed to roll, eg a curb.
faster than that you could get a forward roll, by using something as a ramp, eg a roundabout.
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Ivan
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| posted on 24/12/09 at 02:25 PM |
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Only had one accident - in a Mk1 Escort and it rolled - first tail over nose up the mountain then back down the mountain in a conventional roll - so
for me cars roll 100% of the time. 
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Andi
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| posted on 24/12/09 at 02:29 PM |
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In an X19 down some country lanes, I fishtailed round a damp corner, then veered up a steep grass bank and rolled over twice before landing back on
the wheels. The roll bar did its job but only just, it was proper bent up and skewiff.
Not a 7 I know, but I could still hear the seller a few days before telling me "these things are impossible to roll you know"
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Richard Quinn
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| posted on 24/12/09 at 02:30 PM |
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Never done it in a road car (touch wood!) but have done it in an Autograss car. It happens quite a lot in the Specials classes with them being
open-wheelers and touching rear wheels was often more than enough to get one airborne.
In your average tin top there is now quite a lot of roll over protection contained within the A, B and C pillars but I think it is often
"used" to provide more rigidity to the passenger cell and ensure that only the parts that are meant to deform do so.
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Andy B
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| posted on 24/12/09 at 02:35 PM |
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I think its not just the roll over protection but the added intrusion protection that they offer that is worth considering. For example a few years
ago an RGB Fury race car hit another static one that had spun, head on, the result was the fury ran up the front of the car and bounced off the front
hoop whereas without the hoop the driver would have taken the oncoming car in the head and chest. Whilst thats a race enviroment I have seen the same
scenario plenty of times at incidents we attended on the roads.
I have a very good friend who manged to hit the pit wall at snetterton and virtually stood the car upright on its nose, as luck would have it it fell
back onto its wheels but if it had gone over I think it would have done him a serious injury if not killed him as there was nothing to stop the wall
flattening his head and chest area. Cage was ordered the following day
regards
Andy
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scootz
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| posted on 24/12/09 at 02:36 PM |
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quote:
Originally posted by graememk
As a rule of thumb.
You need to be driving at 40MPH + and hit something while going sideways at low speed to roll, eg a curb.
Not sure of the maths behind that Graeme and not doubting it either, but I feel that there are too many factors in 'real-world' driving
accidents that can cause a 'roll' other than speed and drift angle...
... Type of vehicle...
... Condition of vehicle...
... Road furniture...
... Verge construction...
... Other vehicles involvement...
... Driver inputs...
... etc...etc...etc...
Having been present at a couple of hundred of accidents, my answer to the original question would be... it happens more often than you would think!
I treat Se7en driving pretty much the way I treated my bike... if you have a big-off, it's gonna hurt! A roll-cage is an excellent
investment... any safety feature is. Could (literally) save your life...
It's Evolution Baby!
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britishtrident
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| posted on 24/12/09 at 02:49 PM |
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Cars don't roll over on their own they roll if they slide into slide in into hard contact with a kerb, ditch or banking. If you do the maths
the speed required to roll a tintop is surprisingly slow, in fact the speed required for an end over end roll is also surprisingly slow.
[Edited on 24/12/09 by britishtrident]
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hicost blade
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| posted on 24/12/09 at 03:21 PM |
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I have been messing about with which and what protection my car needs and I came up with the following list of pros and cons of a cage:
Pros:
Roll over protection
Side impact protection
Protection from going underneath something or something going over you (Armco, car, lorry….)
Protection of girlfriend
Stiffens up the chassis a lot
Cons:
Bit of an arse getting in and out
Can be heavy
Can make the car look awful
Can be badly manufactured
Can be badly fitted
Can be badly designed
Can be made from EWR (You might as well not have one)
As I have found with many people in the industry, a lot of bullsh*t goes on with cages.
My specs were MSA approved going by the blue book (if its good enough for racing…)
I ended up with a caged cage only weighing 14kg (lighter than most CDS hoops with back stays and cross brace) with a sticker saying MSA approved (this
I have since found means NOTHING) £850 and a few 16mm holes in the chassis later the alarm bells began to ring.
I then by chance got in contact with Pro Comp who told me how hardly anything in the 750mc Kitcar/RGB/Locost series is actually MSA legal. Off my car
went up to Pro Comp and they have fitted the cage beautifully and correctly.
Caged cages are NOT MSA approved/safe unless the mounts are properly welded into the chassis
If you do decide to go down the cage route do your homework, if I knew about all the pitfalls of roll cage ownership then that I do now, I would have
the manufacturer fit the cage and it would only be between Caged (Pros: look really nice and they very are light. Cons: they are in the arse end of
summerset) or Pro comp (Pros: fantastic customer service/proper engineering knowledge/actually being properly MIRA tested on a Locost/Westfield
chassis Cons: I already had a Caged cage and they are just as far from me as bloody summerset!). I ended up spending more trying to save money (this
is the story of my f***ing car!!!)
To cut a long rant short cages aren’t just about rollover protection, I would not want to drive mine without one. People have been decapitated in
7's going under armco
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scootz
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| posted on 24/12/09 at 03:41 PM |
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quote:
Originally posted by hicost blade
I ended up spending more trying to save money (this is the story of my f***ing car!!!)
Lol... that's the story of my LIFE!
It's Evolution Baby!
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tcc21racing
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| posted on 24/12/09 at 04:09 PM |
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I have a ProComp full cage with side impact J-bar which i am very happy with, for me it actually makes it easier to get in and out of the car.
There are some many seven type cars which you see at trackdays ect with roll hoop which in the event of a crash/roll at speed offer little or no
protection, there is also an issue i find with westfields as the current RAC bar fitted to most of their cars is too low for many drivers over
5"8.
If you draw a straight line from the main front hard point normally the top of the engine/bonnet, back to the to of your roll bar you can check and
see if your head is at risk.
here are two vids that for me made my mind up about changing my westfield RAC roll bar to a full cage, due to tracking the car and using it for
hillclimbs and sprints.
First is a vid of my friend racing MR2's, ok not a seven but the tyre came of the rim suspected puncture, it does highlight what happerns when
hitting gravel sideways at 80+mph http://www.youtube.com/watch?v=iYMoqTDjZbw
Also this is a good one, in a westfield this time http://www.youtube.com/watch?v=NiHLmuyCLDY
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MikeRJ
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| posted on 24/12/09 at 04:14 PM |
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quote:
Originally posted by hicost blade
Can be made from EWR (You might as well not have one)
You might be able to use smaller diameter or wall thickness CDS compared to ERW tube, but if ERW fails at the first sign of impact, what on earth are
you going to weld your roll cage on to (unless your entire chassis is CDS?).
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hicost blade
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| posted on 24/12/09 at 05:19 PM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by hicost blade
Can be made from EWR (You might as well not have one)
You might be able to use smaller diameter or wall thickness CDS compared to ERW tube, but if ERW fails at the first sign of impact, what on earth are
you going to weld your roll cage on to (unless your entire chassis is CDS?).
25mm box EWR is only really any good in compression, this is why most sevens made from 25mm box flex, its a toss up between ease of manufacture and
strength, inch box section chassis being a lot easier and therefore cheaper to manufacture but not ideal (when was the last box section formula ford
manufactured?).
Anyway cages are mounted in such a way that most forces on an impact are in compression and mounted on big thick plates that spread the weight. EWR
has a tendency to split down the seam, Cold drawn steel and t45 do not have this seam and this is why it is used. Making a cage from thick large EWR
is not going to stop it splitting. Most cages are designed to enclose you without relying on much of the chassis strength anyway.
I would love to see what would happen to a reasonably light weight EWR cage if tested properly, A mess probably
Why bother paying some crook (because they would be a crook if they made you an EWR cage) to make you an EWR cage when for probably the price of a
Locost (£250) more you could have something that would actually save your life
t45 a lot stronger and therefore can be thinner but its a right arse to work with and its bl**dy expensive
And clubman spec tube is apparently not strong enough to match the MSA spec so I’m not going to talk about it.
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MikeRJ
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| posted on 24/12/09 at 05:38 PM |
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quote:
Originally posted by hicost blade
25mm box EWR is only really any good in compression, this is why most sevens made from 25mm box flex,
Rigidity is more about design than choice of steel, and plenty of 7 clones (and certainly the book locost) aren't very good in this respect.
quote:
Anyway cages are mounted in such a way that most forces on an impact are in compression and mounted on big thick plates that spread the weight.
Just the conditions that ERW is good at then? Just playing devils advocate here, I'd personaly want a cage/roll bar to be as sturdy as possible
irrespective of cost, but there are plenty of wishbones made from ERW that don't split, and these are probably one of the most stressed parts of
the car.
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Volvorsport
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| posted on 24/12/09 at 05:52 PM |
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you can make it out of 4 mm ERW ? IIRC
so , if its defined in 'the' specs , how does that fair in an accident .
www.dbsmotorsport.co.uk
getting dirty under a bus
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hicost blade
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| posted on 24/12/09 at 07:06 PM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by hicost blade
25mm box EWR is only really any good in compression, this is why most sevens made from 25mm box flex,
Rigidity is more about design than choice of steel, and plenty of 7 clones (and certainly the book locost) aren't very good in this respect.
quote:
Anyway cages are mounted in such a way that most forces on an impact are in compression and mounted on big thick plates that spread the weight.
Just the conditions that ERW is good at then? Just playing devils advocate here, I'd personally want a cage/roll bar to be as sturdy as
possible irrespective of cost, but there are plenty of wishbones made from ERW that don't split, and these are probably one of the most stressed
parts of the car.
Correct rigidity is in the design, but 7 type space frames can’t by definition be design completely in compression and tension.. The front part of a 7
chassis is not very good and suffers from a distinct lack of torsional rigidity; this has an adverse effect on the setting up of a competition car.
But most of us will never notice it so they make them from 25mm box and don’t brace it
When I say cages are mounted in compression I mean the Chassis mountings are in compression not the cage.
Wishbones are under no way near the stress of a cage in a big shunt! Really you want wishbones to break off in a shunt rather than rip your chassis to
bits. Some people use either EWR or CDS or T45 or DOM tube wishbones. Mine are being made from TIGed stress relieved T45
MikeRJ why haven’t you made your wishbones from 25mm EWR box section?? They would be fine if designed correctly wouldn’t they??
Why would you want to use 4mm thick EWR that would weigh more per cm than Dawn French’s ass, but I suppose it would give you more grip, you could even
call it down force!! but not too good through the corners!!
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phelpsa
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| posted on 24/12/09 at 08:07 PM |
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A fellow hillclimb competitor once asked me "what's the point of have £500 in your pocket if you also have your head in your
lap?".
So we have one of these:
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Brommers
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| posted on 25/12/09 at 09:38 AM |
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I agree with the comments about a full cage for road use also being useful for preventing objects from penetrating the passenger compartment. A
friend of mine had an off recently on a tour of Scotland - lost the back end on a wet road, speared off the inside of the corner, and ended up going
down an embankment and through a deer fence. For those of you who haven't seen deer fences, they're about 6 feet tall, made of solid
wooden posts with an open wire mesh between them. He was in a Fury with a windscreen, so the windscreen pushed the wire mesh over the car. Imagine
getting wire mesh in the face at speed though - unlikely to be pretty.
Personal choice, of course, but I'm all in favour of full cages on aeroscreened cars...
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:{THC}:YosamiteSam
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| posted on 28/12/09 at 03:18 PM |
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a few people on here can remember my accident in germany in 2008 when i rolled the dax - we walked away - i never did drive a 7 again without a full
cage - its not because of the roll over - but of things coming into the cabin area - we hit a deer at 50mph, it could of taken our heads off
instantly.. it was nice to see the caged cage doing its job in that video in the westfield series.. it makes me cringe when i see people now with no
rollover protection and just a single bar - some without even diagonals!! i never gave it much thought - until it was too late.. trust me - in a se7en
car you are more vulnerable from objects hitting you head on - thats the biggest threat.
theres some images of the crash in my file on photobucket
here
towards the bottom of the page 
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hicost blade
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| posted on 29/12/09 at 12:21 PM |
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^^that looked scary!!!
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:{THC}:YosamiteSam
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| posted on 29/12/09 at 12:53 PM |
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quote:
Originally posted by hicost blade
^^that looked scary!!!
yea but we walked away without a bruise - compliments to the 4 point seatbelts - i would of hate to think what would of happened in a tin top with
inertia belts - they wouldnt of worked and we would have more injuries for sure..
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boggle
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| posted on 29/12/09 at 02:16 PM |
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i managed to roll my old kart without hitting a kerb.......too low a tyre preasure with very sticky bridgestones....
took a few minutes before i would go back out again.....
allways a worry if you drive any open top vehicle, even with a hoop....would deffo say you you need bracing or it will just collapse....
just because you are a character, doesnt mean you have character....
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