Rollcage: Adding extra bars to it.

[PoloG4tracer]

Hi Guys,

Ive got a track day car that I am now looking at racing this year. As a track day car it used to have a full safety devices 6point bolt in cage (Patterned from the VW PoloG40 Cup Series). We have since welded the cage aswell as it being bolted and added some more bars for extra rigidity, for example triangulation onto the front suspension turrets, and a few more triangulations onto the rear cage. Its a Mk3 VW Polo if that gives you an idea of the cage (although i do have pics).

Its also got a front hoop rollcage, like a space frame where the front end used to be from the turrets onwards.

My question is will these extra bars effect its homologation or rollcage certificate? I assume they will, but not sure if it just requires the scrutineer to check it over and say its ok or its abit more involved?



Thanks All.

Paul Cauldwell

[Al Weyman]

I have extra bars I have added in my cars and they have never been questioned at scrutineering, adding must make them stronger as long as the standard of work is seen to be good of course.

[PoloG4tracer]

ok cheers, that clears it up abit.

[graham bahr]

i turned the 6 point bolt in cage in my old 2002 into a multi point, it went through scruitineering dozens of times until i got the wrong scruit, who didn't like it one bit, i got to race end the end but they weren't happy, despite it being neat and professionally welded, one of my team mates had a similar encounter recently, and got by it with a "what are you on about its always been like it" comment

the biggest problem you have its its obvious if a bolt in cage has been altered, because if the front hoop is bolted in then so should the door bars etc be, or it wouldn't be possible to of fitted it in the first place.

i personally cant see an issue if its done properly, infact my modified 2002 cage withstood me going 2/3rds side on into the armaco at 90mph, the cage and passenger compartment of the car didn't suffer any damage or distortion despite me taking out both the chassis rails, bending the crossmember and peeling the inner wings away from the bulkhead.

the trouble is it does invalidate the roll cage certificate, it can get a bit iffy on the legal side of things if you do an FIA event, because in law if the cage doesn't comply with FIA then technically you havn't got a roll cage.

what i would suggest you do is fit plenty of roll cage padding which will make it far less likely to be picked up unless somones on a mission.
ultimatly at Nat B level its unlikely to cause you a major issue, but it COULD.

[retro_msport]

Originally Posted by PoloG4tracer

Hi Guys,


Its also got a front hoop rollcage, like a space frame where the front end used to be from the turrets onwards.

Thats the killer.... " no part of the rollcage may be past the front axle line"

When you say its a "rollcage hoop" do you mean its 38mmx3mm CDS tubing or better, as i had a car that had stays going to the front chassis ARB mounts and was questioned as to its legality, I said the tube was ERW so is illegal for it to be a cage so its not part of the cage.

Can you remove this part or is it welded to the front triangulation? if its detachable you could get it made in a smaller diameter tube, say 20-25mm tubing, this could then be classed as bodywork mounting tube, not part of the cage.

[Al Weyman]

Did'nt read that bit properly, that sounds rather like the roll cage on my Penske IROC car which is a tubular space frame chassis in effect and every thing hangs off it including the drivers seat and a totally different ball game, mind you this car is like super strong and designed to survive 190mph Daytona crashes with precious F1 drivers at the helm and has raced in this country since the 80's off and on and must have passed many a scrutineering and I would defy anyone to build a stronger cage than this Banjo Matthews produced car BUT as Grahame said I bet somewhere an over zealous scrut would question it.

[Peter Mallett]

The only bars I've added to my cage are the door bars and two lateral bars behind the seat. None of which are welded to the cage.

The problem comes when we weld extra bars and detract from the original configuration. I've seen examples of a "cross" bar being made where the rear diagonal would normally be. I beleive this is a mistake becuase the original bar is designed to work in compression and tension. As soon as you add an extra weld into the middle you create a weakness whereby the forces of an impact are sent in the wrong direction.

[PoloG4tracer]

This is the front hoop in question shown on my garage's mk2 golf, the same is on my polo.

[graham bahr]

as long as that front hoop is'nt directly attached to the roll cage your ok,

i.e is ok if its welded to something else in the vicinity of where the cage is also attached as long as its not become part of the cage itself

[retro_msport]

Originally Posted by graham bahr

as long as that front hoop is'nt directly attached to the roll cage your ok,

i.e is ok if its welded to something else in the vicinity of where the cage is also attached as long as its not become part of the cage itself

Agree with that and it looks like it has the turret between it and the cage

[PoloG4tracer]

no the front hoop doesn't attach to the cage, it comes off the front turrets. Thanks for the info guys, its cleared up some doubts i had of the legality of the build.

[retro_msport]

Originally Posted by PoloG4tracer

no the front hoop doesn't attach to the cage, it comes off the front turrets. Thanks for the info guys, its cleared up some doubts i had of the legality of the build.

If they state that you have a cage out front correct them with ......

"its a progresivly deformable structure"

Which it would do with the bends placed as they are.
The only reservation I would have with that design is containing the engine if you where to T bone a car... thats a big lump, about the same size as a door.

[Al Weyman]

Quite what is the advantage of that complex structure over the standard fletch and front panels on the car as it left the factory, there can't be much weight advantage surely and with respect ir does not look particularly strong.