39 replies to this topic

[SamSmith]

If I was to cut out the bodywork behind the rear seats, would it affect the structural strength of the shell?

[jaydee]

Yes and its a firewall between fuel tank and cabin, in a short, you cant cut it.

[JustSteve]

Your shell will flex like a rule.

And as above, it's needed as a firewall. So, unless you put a fuel tank under the boot floor and fit a cage with lots of bracing, no you can't.

[Tupers]

Don't do it you need the firewall and you need the structure.

[SolarB]

It's not a fire wall. Have you seen how many gaps there are around the rear seat back?

[R1minimagic]

Why do you want to cut it out?

It will reduce the rigidity of the shell quite a bit, obviously the Z cars conversions cut all the rear end out but it is replaced with strengthening/roll cage..

[tiger99]

In a well-designed monocoque, every single part is providing a vital function, rather than being merely excess weight. You can not remove any primary structure without inviting collapse, nor can you remove any secondary bracing without inviting flexing, which will ruin the handling, and fatigue cracking. The seat back is somewhere between primary and secondary structure, and carries significant loading, from the rear dampers for instance. Remove it and there will be fatigue failure around the rear wheel arches.

[MyZeemaxMiniTurbo]

i hear its fine if you get a space frame fitted like z cars ...... i wouldnt say roll cage, this could confuse people to thinking the rear "show" cage will be sufficient with a rear seat removal.... it wont!!!, with a space frame all suspension points mount to the frame, all structural body points that are cut away are replaced with cross members or triangulated frame work, flipfront subframe brace bars mount to the space frame aswell (if you have 1) its almost like putting a chassis in a mini.....almost


i want to do this to my mini also, but i havent found a company that do a space frame for a reasonable price yet, my mate payed £450 for his and took it to somewhere in stratford upon avon, ....but he wont tell me exactly where from (doesnt want another mini to look like his)

as for the whole monocoque argument, its all true so be carfull what your cutting away untill you fit a decent cage, then the whole thing gets a bit grey on whats acceptable or not,
all im saying is we heard of a guy that cut the back seats out and decided he didnt want a cage, thinking he knew best, drove round for a few days fine, he then decided to lower it, he jacked up the rear passenger side to get to his high lows, the car went back down pringle shaped and never drove right after, jacking it up had twisted it, almost beyond repair, the story goes, he had to re-shell his mini....and now rolls about with a cage.

so at least think of properly caging up that which your cutting. you dont what to ruin your mini.

[tiger99]

Fortunately he only ruined his monocoque by jacking it. As such, I have no sympathy for him, if people want to be completely stupid, they must accept the consequences. It could have happened at speed on the road, which would be very bad, and may have affected other people.

A cage is made only to give rollover protection, and unless it is fully triangulated will not restore stiffness, particularly in torsion, to the shell. It is a rather heavy way of restoring the stiffness provided by a well designed bulkhead, and it raises the centre of gravity.

[ANON]

...we heard of a guy...the story goes...

i heard of a fairy that takes teeth from under your pillow and leaves money for them...don't mean it's true.

if cutting the rear shelf and seat back out turns your car into a jelly on wheels that will fold in half when you go over a bump...why are clubby estates/vans still structurally sound?

[tiger99]

Take a look on somewhere like the Somerford Mini web site at all the parts that go into a van or traveller shell, and then you can answer your own question.

The van and traveller are not as torsionally stiff as the saloon, even though there is a fair degree of reinforcement in various places.

[ANON]

i know what goes into them, just something that always pops into my head when threads like this crop up.

[tommypope]

i think he means can he cut bits from behind the firwall without bracing.....

[tiger99]

No, the boot floor, wheel arches, and various reinforcements are all primary structure and can't safely be removed.

[MyZeemaxMiniTurbo]

...cant?...

SPACE FRAME!!! yes you can!