To roll cage or not to roll cage, that is the question

[miniphil30]

Hello all,
Just wanted a few honest opinions on the above really.
Currently at a stage of the build where I can go either way.
My ideal was to keep the Mini looking as standard as possible so wasn't going to fit a roll cage. It will be mainly used for fair weather road driving rather than racing or hill climbs. Yes I may do the doo track day.
It was a 1996 shell and has the side protection in the doors, air bags, etc. (However good that is)
People on here will have crashed minis with or without cages.

I'd be more worried about the frame and engine coming through the floor/bulkhead than rolling but not sure how to improve that.

If a cage is essential in improving safety which one can be fitted with minimum visible disruption?

Cheers
Phil

[AGoaty]

Something to consider. Ring the insurance company before adding one. Quite a lot bump a premium on for a caged car.

My experience is so far in my life I don't feel it necessary. I have done a few track days and although slid into grassed areas and my son hit a barrier causing quite bad damage, we have come away without any physical injury to ourselves.

He also rolled a Mini a few years ago. Was very serious crash. He came home with a bruised elbow. He will not set off with his mates in a car now without all of them having a seatbelt on. It saved his bacon that day.

Obviously there are arguments for the cage. I have one in my Project Scorpion. At the end of the day, only you can decide.

[edk83]

After driving my Allegro in a spirited way I decided I wanted a full cage, it really wouldn't stand up that well against anything hard.

I also really wanted to use harnesses as they give me much more confidence over a normal seat belt.

Insurance is something to check up on, there are brokers that will accept cages though.

It's also worth noting that a badly designed or fitted cage will also kill you faster than not having one. Not that anyone does but I'd always recommend wearing a helmet with a cage, even the padding is rated for helmet impacts not your head, obviously not going to be wearing one everywhere on the road but worth thinking about the consequences.

If you buy a cage make sure it's msa approved or build one to specs from cds tube of the correct rating. a show cage is also just going to kill you!

If done right the cage will add a huge amount to strength to the car and stiffness which will help handling. It will also add weight though mine is about 70kg.

Lastly, front bulkhead / engine landing on feet protection. This is also something I was wanting, not many off the shelf cages seem to offer this and my bulkhead is thin!

After consulting a friend that races grass track cars see below I have a bar that goes around the bottom of the bulkhead, this is also tied into the subframe mounts and tunnel, with gussets to the A pillars.

[edk83]

[PaulW]

If I was going to build another for the road I would not put a cage in. I would design something around the frame mounts as Andrew suggests. It's a pain in the peach getting in and out and if you ever carry a passenger in the back with a cage it's not practical. I Wouldn't fit a harness either for a road going valve

[ardonfast]

Paul's hit the nail on the head,!! Exactly as he has said,!!
If you're numbers called, a roll cage won't save you,
What's the investment? £300_£600?
Spend it on something else that you can feel and enjoy
On a daily basis, like brakes or a nice music system,

[Oz]

My 2ps worth is that a roll cage is designed for competition and as such it should be used in conjunction with race seats and harnesses. The rear roll hoop is usually placed right where your head would be when you put a set of decent aftermarket seats in to get a more legs stretched seating position. an un-helmeted head against a thick steel tube is going to be pummelled - arguably the same would be said about a Mini B pillar tho'.

There are countless videos on you tube of in-car footage of the occupants in a crash (I'm not talking about the ncap crash tests but real crashes and real people), take a look and you will be amazed at how much a body moves around even when belted in. Think about all those lovely thick tubes and how many opportunities you'd get to bash your skull on it in various places.

I hear you about the engine coming through the bulkhead, a cage by itself won't stop that. One thing I saw years ago on a home made frame (can't remember whos - fbm-spec comes to mind but I can't be sure) was that he'd extended the rear mounts under the floor and bolted either side of the seat crossmember. It's something I am considering for my current rebuild as it would effectively brace the driver cell area and hopefully transfer some energy in to the shell behind the crossmember rather than simply driving the frame and engine through the bulkhead. Ideally something would also need to be done to brace the tower mounts to help prevent the frame twisting instead.

A word of caution however, everything you do to strengthen the shell means the energy of a crash has to go somewhere else to dissipate and that somewhere is usually to the occupants. The idea of crash structures are that they crumple in a controlled manner to absorb the energy, that is well known, but what is understood less is why, its so that it channels the crash energy in to the shell so that less is transmitted through the occupants. Its like the old saying, jumping off a building does not kill you it's the sudden stop at the bottom that does it. Its the same in a crash the more you can do to reduce that "sudden stop" in a crash the more likely it is that you will survive it (like a stuntman jumping off the building into a large air mat) so conversely by stiffening the car there will be less absorption by the car itself (like filling the air mat with concrete) which means the occupants suffer it instead increasing the chance of death.

Minis do crumple in accidents (there's no actual crumple zone - or at least in our cases we are filling the potential crumple zone full of a much larger engine and box etc).

Also ask yourself this, is there a difference between a 998cc A-series mini crashing at 70mph and a 16v Mini crashing at the same speed ? No, not really, so would you be wanting a cage in a 998 Mini ? If not then why is it so important to you in a 16v Mini ?

Bottom line is that any Mini is dangerous compared to a modern car, if that bothers you to the point you are worrying about it then you should be wondering whether Minis are for you

[Bennjaminozhonda]

I’ll add a few cents or p

As above - IMO a roll cage should never be used in a road car. It will transfer more energy
into soft occupants and without protection they will turn to mush.
Consider a removable rear roll cage (for roll overs only) to have an option for street and track.

Also , if you haven’t considered - get a collapsible steering column and fix your seat to the floor (rather than having it hinge forward like standard) These two fixes will save your life up to a certain speed and situation.

[miniphil30]

Some Brilliant replies here, thank you very much.
Minds made up
Leaving the cage out.
I may put a thicker or larger patch into the floor where the frame mounts. Or tie something into the cross member.
The interior of the car was one of the reasons I chose it for a project. Full Mini cooper leather set up, loved it. I didn't want to spoil that look with a cage.

Thanks again, now my time goes back to the wiring loom...and a 4 month old!

[ardonfast]

Good choice, and the engine will not come in through the bulkhead at you,
And if it does your mincemeat anyway!
Crack on and enjoy!!

[Bennjaminozhonda]

Drive a mini like you would a motorbike.

That is - like you are invisible , and screwed if you have an accident.

Hey , that’s part of the fun !