FIA Rollbar height issues.

[SvenDriver]

I have a 40th Aniversary with the standard Rollbar and standard seats. I'd like to fit an FIA bar ready for Track. I have a little problem though - I'm 6 foot tall. I sat in someone elses 7 today who already have an FIA bar and similar seats and the measured clearance between my head and the top was about 7.5cm to mid-bar. Now I've measured some helmets and reckon that they will increase my height by about 3-4cm. I think I'm going to miss the 5cm clearance requirement by a few cm.

 

I normally run with the seat fully back on the rails so that the headrest is real close to the bar.

 

Any ideas?

 

P.S. I think a single vertebrae is about 3cm but I need them all.

[felix.klauser]

You're wise to understand your position, no pun intended. I don't think the 5 cm clearance is a rule for anyone's track days but it is a very very good idea so that the bar can protect the occupants properly.

 

There is a tall FIA bar available but your hood will no longer fit properly. Oxted Trimming, original makers of the hood for Caterham, can modify it but I'm not sure what the cost is.

 

You can also go to a different seat that reclines you further, thereby lowering your head.

 

I would suggest actually measuring things with a helmet and then considering the options.

[SLR No.77]

By all accounts you're not going to have a problem with club track days - the 2" rule is there as enforced by the MSA, but there is clearly little enforcment within the club - it's a recommendation remember. This should cause a response from those involved, but there are participants on the club track days who are clearly above the 2" below the bar limit. Quite honestly, I'm just short of 6', and even with the seat swab removed, sat on the floor, I struggle to comply with the MSA regs with a helmet on - the FIA bar as supplied by Caterham is so obviously a compromise between the manufacturing specification required by the MSA, and a height that will fit under the standard hood. Nobody in authority seems to see it that way, but the argument will go on and on. Racers use higher bars - unless you're under a height of about 5'10", or are reasonably short in the body you're going to be too tall for the FIA bar with respect to the MSA regs. Answer - slouch a bit in the seat like everybody else does. This is a seriously controversial issue, but if the powers at be face up to the problem fully, it has to be accepted that the standard FIA bar does not fulfil the MSA requirements in many many cases. But then should the MSA rules be applied letter by letter for track days - even more of a controversial subject.

 

Stu.

.

[SvenDriver]

OK. I understand that I can slouch and 'get around' it or whip out part of the seat or ignore it. That is really not the issue. I'd first like to understand why the rule exists before I decide whether or not subverting it is a thing I wish to do. I am assuming that 5cm is not just an arbitrary number but does buy some margin of safety such as allowing for belt movements etc during an inversion.

 

Does anyone know why the requirement is 5cm and not 1cm or 200cm???

[steve_m]

I would imagine that if you crashed and your helmet was too close to the roll bar then the roll bar would start damaging the helmet before it had a chance to protect you.

 

Also if you roll over on soft ground you don't want your head too close to the roll bar as the bar will dig into the ground to some degree - you want some clearance between you and the ground or I think a neck support may be required, if you're fortunate.

 

 

[felix.klauser]

5 cm really is the bare minimum. If you were to remove your bonnet and nose cone and then put a long straight edge with one end on the chassis at the cruciform by the front suspension and the other end on top of the fia bar you would see the derivation of the 5cm. Add to that any belt slackness and stretch and when the car is upside down your helmet is very near to forming a part of the roll over protection for the car.

 

I've seen what happens to the head of a person in an open car without sufficient rollover protection. That image will never leave me.

 

(spelling error corrected on 9/12/02)

 

Edited by - felix.klauser on 9 Dec 2002 22:42:54

[PeterS]

Note also that MSA have just changed their rules on this from 50 mm below a horizontal line from the top of the bar, to 50 mm below the sloping line as described by Felix.

A recent trackday incident rebounded on the MSA because they had issued a licence to the track. This means that MSA are looking seriously at their liability for safety issues on trackdays, which are the fastest growing sector in motorsport. You may find that in the future MSA will impose the same standards on trackdays as they insist on for our Sprint days at Curborough. If that is the case, the clearance will not be just a recommendation.

At the end of the day, the most important consideration ought to be how much you care for your head and neck.

[SLR No.77]

The 50mm measurement is there for damn good reason, and it has to be assumed that it is a figure created and justified by the MSA due to their vast experience with respect to soft ground, vertical body movement etc., with a consideration for many types of open car.

Quite obviously, it is not for us to judge or question a ruling by the MSA from our uninformed standpoints. However, we can question Caterhams interpretation of the measurement, and I still maintain that with a standard height Caterham FIA rollbar, the average height male is already at the 50mm point.

Peter, if as you say the new ruling by the MSA is to be acted upon at club track events (which I wholeheartedly would agree with baring in mind the reasons behind it) then either there is going to be alot of unhappy non-participants, or drivers well adapted to crouching whilst in the paddock. The standard Caterham FIA bar is plain and simple not high enough.

Stu.

[PeterS]

Stu

Don't jump the gun! The new ruling from the MSA only applies to competitive events i.e. for the Club that means the sprints. Trackdays are still NOT covered by MSA rules. However, for the reasons I explained, MSA are reviewing their position on this. They MAY decide that they must get involved in trackday safety rules.

I entirely agree with your stance on the 50 mm, and as someone who has to use the tall FIA bar, I agree with your views on the height of many Club members.

At the moment the Club's position is to warn and advise. The final decision is being left to each driver. Let's face it, you are only taking the top off your own head (unless your passenger is also tall) and you are responsible for your own safety.

The alternative would be for the Club to start throwing people off track for not complying with the 50 mm rule.

Slouching in the paddock seems a pretty immature way of putting your head at risk. The person who feels the damage is yourself, the marshal you "fooled" in the paddock won't feel a thing.

[SvenDriver]

What's the deal with the Tall FIA rollbar then? Is it from Caterham? How much taller is it and is there any hood available for it?

 

Is it possible to do a hybrid? Fit a standard FIA rollbar and then buy a bolt-on braced hoop to give the necessary height?

 

I hear what people are saying. I'll measure up exactly using a piece of string but I think it'll be at best close. I now understand why the 5cm margin is there. Seems sensible. I had a quick look around the house; I don't have a spare head. This will enter into my considerations.

[PeterS]

The tall FIA bar is available from Caterham, and is 50 mm above the normal one.

 

Incidentally, the FIA approval was given for the rollbar with the Petty strut (i.e. forward brace) fitted.

 

It is possible to get a roof made to fit over the tall FIA bar. Caterham Midland should be able to point you in the right direction, if you can't get it anywhere else. I have had one of theirs for a few years.

 

I always worry about the bolt on additions. It seems to me that you introduce a plane of weakness in a place where you don't want it. Forward momentum, whilst inverted, might wipe the extension off. I'm sure that such a bolt on doesn't comply with the MSA/FIA rules. I suppose a properly designed welded joint might work, but I'd still be worried whether the rest of the bar was designed for these unusual stresses.

 

If the tall FIA bar isn't enough, then a race cage changes the situation drastically with regard to the fall line, but you've still got to be sufficiently under the cage. Looks a bit of a pose outside Tesco though.

[scooby dooby doo]

you can have a hood modified (although its not that cheap as extra material has to be added) to fit over the tall bar.

 

I'm biased in that I don't have a hood (or windscreen for that matter 😬), so I'd say get the big rollbar and sell the hood to fund it...

 

HOOPY 500 kg R706KGU

[SLR No.77]

An alternative approach that I've used due to being very aware that I am higher than I ought to be, is to add washers under the front seat mountings to recline the seat slightly. This option depends greatly upon your leg length vs comfortable driving position, but with the pedals in the forward position, it is usually possible to gain some rake. It is quite surprising how little you need to add to lower your relative head height. I initially added an nut to each of the front seat bolts before refitting the seat, although I have now backed off to a couple of washers. The extra nuts certainly made refitting of the seats alot easier though!.

 

Stu.

[scooby dooby doo]

Optimum comfort seems to be about an inch of spacers in there. I think I want a tad more (need to fiddle a bit) and I know some with over 2" (purely for comfort - he's not got height problems).

 

HOOPY 500 kg R706KGU

[Gordon]

I take the seat base out and sit on a piece of foam...this has done the trick for me at 6' tall........

 

Gordy