Rollcages - what are the options?
Discussion
The difference in weight between an FIA bar and a cage is surprisingly small (I’ve not weighed them, but...) so I wouldn’t let weight or CoG make your mind up. Making a bar which is only braced in one direction stand up to the weight and impact of a rolling car necessitates larger heavier gauge tubing than a cage which can be braced in all directions.
Weight (possibly) offset by extra bracing? (and as said, it's not that much). The only real reasons for not having a cage that I can see are convenience of entry/exit (but I kinda liked the sense of occasion), and the need to wear a lid on the road. IMHO you'd be mad to drive a caged car without, which is why mine went back to a bar. YMMV.
HustleRussell said:
OK that makes sense.
I think the difference with Caterhams compared to tin tops is that they are very lightweight and softly sprung. The Caterham chassis is not the stiffest in existence but it doesn't need to be.
I bought a Caterham road car which I converted into a race car. I did a trackday with an FIA bar and then used the car with a cage from that point forward. I didn't notice any difference in feel or handling with the cage.
Obviously in a tin top, you stiffen the suspension right up to make it corner on track and then the body can't cope with it, in this instance a cage, particularly one which ties in to the inner wings / strut top mounts, can have a transformative effect.
In a Caterham it just doesn't work that way, whichever cage you buy the front attachment points are always going to be about four feet aft of the front suspension pickup points.
By all means fit a cage for safety or because it looks C.A.F. though.
P.S. I'd never have a hoopy cage, I am 28 years old and not that fat and by the time you have the FIA padding on there they are horrible to get out of.
P.P.S. Consider also side impact bars if required, you may find some don't work with certain cages etc.
I have a 'hoopy' cage on my car ('98 SLR). The cage, whilst only picking up on the chassis circa 120cms behind the top front wishbone mount does add a *lot* of torsional (and longitudinal) stiffness to the car. If you are considering a 'Caged' cage, ask Phil Squance to show you the FIA homologation tests they do via applying 'stress' in the approved Finite Element Analysis package, and see what a difference the cage makes. The suspension can then do it's job independent of the chassis flexing.I think the difference with Caterhams compared to tin tops is that they are very lightweight and softly sprung. The Caterham chassis is not the stiffest in existence but it doesn't need to be.
I bought a Caterham road car which I converted into a race car. I did a trackday with an FIA bar and then used the car with a cage from that point forward. I didn't notice any difference in feel or handling with the cage.
Obviously in a tin top, you stiffen the suspension right up to make it corner on track and then the body can't cope with it, in this instance a cage, particularly one which ties in to the inner wings / strut top mounts, can have a transformative effect.
In a Caterham it just doesn't work that way, whichever cage you buy the front attachment points are always going to be about four feet aft of the front suspension pickup points.
By all means fit a cage for safety or because it looks C.A.F. though.
P.S. I'd never have a hoopy cage, I am 28 years old and not that fat and by the time you have the FIA padding on there they are horrible to get out of.
P.P.S. Consider also side impact bars if required, you may find some don't work with certain cages etc.
I'm almost 6'6", and around 105kgs and get into the car through the roof. It's no massive inconvenience, even with FIA padding fitted around the hoop section.
fergus said:
I have a 'hoopy' cage on my car ('98 SLR). The cage, whilst only picking up on the chassis circa 120cms behind the top front wishbone mount does add a *lot* of torsional (and longitudinal) stiffness to the car. If you are considering a 'Caged' cage, ask Phil Squance to show you the FIA homologation tests they do via applying 'stress' in the approved Finite Element Analysis package, and see what a difference the cage makes. The suspension can then do it's job independent of the chassis flexing.
I'm almost 6'6", and around 105kgs and get into the car through the roof. It's no massive inconvenience, even with FIA padding fitted around the hoop section.
Interesting, does that additional stiffness actually translate to any tangible performance advantage though- I can't imagine a Caterham chassis does much flexing with ~600kg and ~225lb springs. I'm almost 6'6", and around 105kgs and get into the car through the roof. It's no massive inconvenience, even with FIA padding fitted around the hoop section.
ForzaGilles said:
BertBert said:
I know it's personal taste, but I wouldn't go for a cage to look cool and stiffen the chassis. In my view it makes a fun car a bit tedious and scuttle shake is not a normal criticism of a Caterham!
+1Personal choice though.
In most cars I'd agree that driving with a cage and no helmet is very dangerous and to be avoided. However, in a Caterham if you bin it hard enough that your head hits the cage it's also very likely that you'd be killed or seriously injured if the cage wasn't there.
On track I want a cage, a proper seat and harness and a HANS device. On the road you're so vulnerable that you're essentially gambling that the type of accident you have will be manageable with the safety systems that you've implemented. There are situations where having a cage and no helmet will be Very Bad. There are also undoubtedly times where having a cage and no helmet will be better than being in a Caterham with just a normal roll bar. Side impact from other vehicle, strike object or animal in the road that comes over the bonnet. Front collision with object that the car nose fits under like a HGV etc.
There are too many variables and blanket stating that one option is wrong is incredibly misleading.
We all make our choices and live (and potentially die) by them. This topic was posted to try to ascertain what different cages weigh and the benefits of one type of cage over another. Please, please have a discussion about cages v rollbars elsewhere. Ta.
On track I want a cage, a proper seat and harness and a HANS device. On the road you're so vulnerable that you're essentially gambling that the type of accident you have will be manageable with the safety systems that you've implemented. There are situations where having a cage and no helmet will be Very Bad. There are also undoubtedly times where having a cage and no helmet will be better than being in a Caterham with just a normal roll bar. Side impact from other vehicle, strike object or animal in the road that comes over the bonnet. Front collision with object that the car nose fits under like a HGV etc.
There are too many variables and blanket stating that one option is wrong is incredibly misleading.
We all make our choices and live (and potentially die) by them. This topic was posted to try to ascertain what different cages weigh and the benefits of one type of cage over another. Please, please have a discussion about cages v rollbars elsewhere. Ta.
Unfortunately not. I'm more informed than before I started the thread but my only real conclusion is that the different options have different pros and cons. I've agreed to buy a simple roadsport cage (single diagonal top bar rather than double-D), mainly for the weight benefit as it seems to be the lightest from what I can ascertain but as I've decided to swap the scuttle for one without wiper holes, will be running without a screen and have a carbon tonneau for the boot I guess I've moved away from the ability to use weather gear anyway so may change to a double-D SLR to gain more space within the cabin / better roll protection. That would allow me to use the carbon half-doors I have too unlike the Roadsport.
Edited by 573 on Monday 12th March 13:38
Had DD cages on super light R , R400 x 2 and R 500. Stuffed 2 of them quite substantially at Oulton, but not flipped. Both back on the road after chassis works and jigging. The engineer did say they thought in one case the cage had limited the damage. I’ve seen two flipped and one endoded at anglesey and honestsley if you’d seen the cartwheel incident you’d think the driver would have been killed. If he had had a bar I think he would judging by the amount of soil and grass in the cockpit.
Personal choice but for me if you’re driving to the limits of your ability and the cars it’s no contest, for road work not so important. when you consider that almost anything you’re going to hit or be hit by is going to be taller makes me think a bit. You can still keep your screeen and wipers with some of the DDs by the way, ask Arch.
Personal choice but for me if you’re driving to the limits of your ability and the cars it’s no contest, for road work not so important. when you consider that almost anything you’re going to hit or be hit by is going to be taller makes me think a bit. You can still keep your screeen and wipers with some of the DDs by the way, ask Arch.
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