I know we have discussed the subject of seat back braces before. I just got through re-reading the IOPort people's FAQ about it.
They contend that composite seats will bend back under impact, which is good but that will result in a loose harness, and possible injury upon recoil. OK.
Seat manufacturers do not recommend using braces with their composite seats. OK.

I have found a really cheap Kirkey eco seat to use for the passenger side of the civic, and I will buy a brace for it. But now, I am wondering if I should also add a brace to my sparco Pro2000. I know that I am not required to since the seat is FIA certified, but I'd like to be as safe as possible (duh). So, does anybody know if it is safer with a bolted brace, non-bolted brace, or with no brace at all?

I welcome everyone's opinion, and would greatly appreciate real data as well, if available. Also, we have some very serious racers on this board (professionals, or nearly professionals) and I would be curious to hear what they think and use - I seem to recall that Gary Sheehan was moving towards an aluminium seat for safety reasons?

thanks in advance.
S.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SJR &raquo;</TD></TR><TR><TD CLASS="quote"> I am wondering if I should also add a brace to my sparco Pro2000</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SJR &raquo;</TD></TR><TR><TD CLASS="quote">Seat manufacturers do not recommend using braces with their composite seats.</TD></TR></TABLE>

*shrug*

 

yeah - my thinking as well. Actually, I have been digging a little deeper in the archives (and weegin out useless hits), and from what I saw there, it appears that the post 98 FIA certified seats were tested with and without a brace and seemed to show it was worse, and more dangerous, with a brace. Again, that's second hand hearsay to me, I'm just looking for confirmation I suppose.

RJ, maybe we should add the seat brace thing to the FAQ? Or is it already there?

Thanks
S.

 

i would think that anything that keeps the seat from moving around is a positive thing.

the only reason i would be concerned is the brace actually penetrating through the seat itself in a severe rear-end incident. since the seat manufacturers have no control over the design of said braces (and since racers tend to conjur up their own hackjob creations), it is in their interest to not officially support it. ioport is about as reputable as you can get to my knowledge, and i trust pretty much anything they say.

EDIT:
i forgot to mention you're FIA seat. i'm not sure what seat you have, or how FIA seats differ from SFI. but on my friends SFI seat it has a frame on the inside, which the brace must be connected to. or maybe your seat has a fiberglass/carbon fiber shell. in which case i can invision the brace and its associated hardware essentially tearing through the material, whereas steel or aluminum might hold its shape better. i dunno, just spontaneous thoughts on my part.


Modified by tnord at 4:30 PM 1/28/2004

 

here's my problem:
IOPort wants to sell me a brace.
Sparco wants to sell me a seat.

I have a hard time blindly trusting ANY vendor's advice. know what I mean?

 

Seb, I absolutely refuse to take responsibility for what I will say, only that this is the way I view it for my own safety sake. There is a great amount of technology involved in building seats, be it from Aluminum to Composite seats. On Speed a few months back, the chief safety steward for Nascar made the comment that one of the reasons that Aluminum is widely approved and composites are not is based on the ability for the teams to manufacture/fabricate w/ aluminum well and relatively easy vs. the complexity of development w/ composites (in a safe manner). I personally feel very safe with my Momo composite seats with no bracing (as it is designed as such) and I would feel equally as safe with a Butler Built custom Aluminum seat with a back brace. Different seats with different ways of working as far as I am concerned and I personally would only run the seat per its design. Again though, this is all about me, not remotely telling you how to be safe and sound.

 

Don't trust anyone blindly, go to the source...

directly from FIA's site here is an excerpt from the testing done in order to achieve their 8855-1999 rating for competition seats:

"2.Dynamic tests:

Dynamic tests shall be carried out using a catapult sled in the rear and lateral crash directions. A 50th percentile Hybrid-II or Hybrid III dummy shall be used, firmly maintained in the seat by a safety harness with a minimum of 4 points homologated by the FIA. The type of dummy used shall be mentionned in the test report.
The seats shall be positioned to comply as closely as possible with the standard position shown in drawing 3 and any differences between the standard position and the real position shall be mentionned in the test report.
The position of the footrest shall be such that the backs of the dummy's thighs are in contact with the edge of the seat.
The length of the shoulder straps measured on the inner side of the strap, between the mounting point and the rear of the seat shall be 200 -0+50 mm (drawing 3b). The mounting of the harness shall be in conformity with the FIA's recommendations (drawing 4).
The feet of the hybrid shall rest upon and be attached to the footrest. The arms shall be crossed and the forearms shall be taped together with adhesive tape. No other attachment shall be present.
The distance D, between the seat and the post to which the harness is attached, shall be a minimum of 150 mm.

Exceptionally, it is possible to fix a minimum of non-energy-absorbing foam onto the dummy, in order to cover any protruding parts it may have. Under no circumstances may the foam be fixed onto the seat. The dimension and type of the foam and its locations on the dummy shall be mentionned in the test report.

The deceleration of the sled shall be measured by means of a class 60 measuring chain, in accordance with the SAE J 211 standard, and corresponding to the characteristics of the ISO 6487 standard.


These tests shall be as follows:

1.Rearward impact: a deceleration of 20 g minimum measured over a minimum non-cumulated duration of 50 ms in which the deceleration curve is within the corridor of drawing N° 5.
If the deceleration curve of the sled is not within the corridor, the test shall nonetheless be considered valid if the total mass of the sled (mass of sled + dummy + seat + accessories) is greater than 685 kg and if the calibration curve of the sled ballasted to 685 kg is within the corridor of drawing N° 5.


2.Side impact: a deceleration of 15 g minimum measured over a minimum non-cumulated duration of 50 ms in which the deceleration curve is within the corridor of drawing N° 6.
If the deceleration curve of the sled is not within the corridor, the test shall nonetheless be considered valid if the total mass of the sled (mass of sled + dummy + seat + accessories) is greater than 685 kg and if the calibration curve of the sled ballasted to 685 kg is within the corridor of drawing N° 6.

3.Rearward impact: a deceleration of 10 g minimum measured over a minimum non-cumulated duration of 50 ms in which the deceleration curve is within the corridor of drawing N° 7.
If the deceleration curve of the sled is not within the corridor, the test shall nonetheless be considered valid if the total mass of the sled (mass of sled + dummy + seat + accessories) is greater than 685 kg and if the calibration curve of the sled ballasted to 685 kg is within the corridor of drawing N° 7.
The purpose of this last test is to check that following the first two tests, the seat remains without breakage after a further impact.


3.Performance requirements:

3.1When tested as specified in point 2, the structure of the seat shall remain intact, with no fracturing, separation, or cracks visible on both sides of the structure.
3.2Subject to the above conditions, permanent deformations may be accepted, provided that these would not increase the risk of injury.

3.3Following testing, the seatback adjusting systems, if they exist, may be jammed but not broken."


The non-rated, aluminum seats do not have to undergo any type of testing AFAIK, and require a seatback brace to prevent them from bending/buckling.

The FIA rated composite seats are tested and designed to protect the driver from injury without any additional bracing...in fact additional bracing could very well prevent the seat from doing it's job and even damaging it...

Personally, I would NEVER, EVER put a backseat brace on an FIA rated seat. EVER.

As to which design is really safer, I don't know....but from what I gather...I'd rather have something that will give and deform in an impact while still protecting my body instead of something that will transfer all the force into it.

For instance, how many aluminum seats do you see in WRC cars? Cars that are involved in spectacular crashes from time to time...with drivers walking away...

With that said, I don't really know for sure how much or how little design goes into aluminum seats, nor am I positive that there isn't any type of testing that these sets go through...but I, personally, would rather have something that is tested as rigirously as the FIA mandated test....

Hope that helps,

Matt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
For instance, how many aluminum seats do you see in WRC cars? Cars that are involved in spectacular crashes from time to time...with drivers walking away...
</TD></TR></TABLE>

this may or may not have something to do with comfort. as much banging around in the seat as they do, i can see how some aluminum seats might be pretty painful to sit in.

in summary...

aluminum seat + brace =
FIA seat with no brace =
FIA seat with brace =

 

I think ANY seat should have a seatback brace , period.

think of how much load it takes off the bottom mounts.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Doctor CorteZ &raquo;</TD></TR><TR><TD CLASS="quote">I think ANY seat should have a seatback brace , period.

think of how much load it takes off the bottom mounts.</TD></TR></TABLE>

...and puts in a spot where the seat is not designed to take it (in the case of an FIA rated seat)...

a really bad idea in my humble opinion...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by El Pollo Diablo &raquo;</TD></TR><TR><TD CLASS="quote">

...and puts in a spot where the seat is not designed to take it (in the case of an FIA rated seat)...
</TD></TR></TABLE>

true.

I just know how much more solid a bucket becomes when it has a seatback brace , and I'm not talking about these generic p.o.s. ones ya buy , I'm talking one that is designed for the seat and cage and firmly bolts to both.

 

Right, and do you really want to be in a caged car, with a seat attached directly with no give? I don't.

What is going to end up absorbing the decceleration? Your body...

I'll take a seat that's designed to have some flex to it to reduce the force excerted on the body anytime.

Obivously, there is no clear cut choice here, as no accidents are ever same...but...it is food for thought.

Matt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by El Pollo Diablo &raquo;</TD></TR><TR><TD CLASS="quote">Obivously, there is no clear cut choice here, as no accidents are ever same...but...it is food for thought.

</TD></TR></TABLE>

exactly.

both are valid ways to think about it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
Right, and do you really want to be in a caged car, with a seat attached directly with no give? I don't.
What is going to end up absorbing the decceleration? Your body...
</TD></TR></TABLE>

the same theory can be applied to roll cage design in the way of nascar bars....kindof. nascar bars require the removal of the door upholstry, bracing, and everything else besides the skin. then the bars are placed as close to the skin as possible. now what happens in a side impact? the door doesn't absorb any energy at all, and the other car smashes directly into your cage. since the cage is solid and attached to many other points of the car, it theoretically would send the car flying around like a ping pong ball, whereas a car without the nascar bars could potentially absorb much more of the impact (as the factory designed it). now what really matters is how the driver fairs in this situation. that is an outcome i have few relevant thoughts on.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tnord &raquo;</TD></TR><TR><TD CLASS="quote">

the same theory can be applied to roll cage design in the way of nascar bars....kindof. nascar bars require the removal of the door upholstry, bracing, and everything else besides the skin. then the bars are placed as close to the skin as possible. now what happens in a side impact? the door doesn't absorb any energy at all, and the other car smashes directly into your cage. since the cage is solid and attached to many other points of the car, it theoretically would send the car flying around like a ping pong ball, whereas a car without the nascar bars could potentially absorb much more of the impact (as the factory designed it). now what really matters is how the driver fairs in this situation. that is an outcome i have little relevant thoughts on. </TD></TR></TABLE>

You're looking at this the wrong way....the nascar bars should be placed as far away from the driver as possible...hence the door skin removal etc...and their purpose is to prevent the other car entering into the driver compartment...

A car without nascar bars, or other side protection would bend inwards and contact the driver...

Matt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by El Pollo Diablo &raquo;</TD></TR><TR><TD CLASS="quote">

You're looking at this the wrong way....the nascar bars should be placed as far away from the driver as possible...</TD></TR></TABLE>

exactamundo.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
You're looking at this the wrong way....the nascar bars should be placed as far away from the driver as possible...hence the door skin removal etc...and their purpose is to prevent the other car entering into the driver compartment...

A car without nascar bars, or other side protection would bend inwards and contact the driver...

Matt

</TD></TR></TABLE>

i understand that they should be placed as far away from the driver as possible, and the result is that they are right up against the door skin. their purpose is the same as any other doorbar, be it nascar style or not. all i'm saying is that with nascar bars there is a greater amount of force applied to the cage than there would be had the door bracing and reinforcement been left in place. i assume this is why there is extra bracing with nascar bars compared to a single door bar. cages don't bend much, so the result is that the energy gets transferred to the chassis, potentially sending the car careening across the track into other compeitors and/or objects. as i stated before, i have no knowledge in the area of how this affects the driver, as protecting him from impact is the issue of utmost importance.

-rodney d.

 

damnit - I was all ready to buy a kirkley aluminum seat and was feeling pretty smug about being super safe, and now I read this thread

if aluminum seats aren't FIA-approved, then how are the legal for racing?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Greyout &raquo;</TD></TR><TR><TD CLASS="quote">if aluminum seats aren't FIA-approved, then how are the legal for racing?</TD></TR></TABLE>

they are with the addition of a seatback brace.

 

i'll throw in my 0.02 here....

i was in a fairly violent accident in a 100% stock streetcar some years ago -- high speed crash where the rear of the car hit a concrete barrier. Recaro seat broke completely in half and i ended up looking straight up thru the moonroof as the car came to a rest (it was a VW GTI).

seatbrace would have prevented that seat from breaking in two.

both of my racecars have custom seat braces. i built 8" tall X the width of the seat steel plates to capture the seatback. these have little "wings" on the sides to give additional sideways stability. they are secured to the seatback by means of U shaped rods which attach to the steel skeleton of the seat. makes the seat very secure.

in the event of a severe rear impact, i want the seat to remain more or less immovable. i will allow the crush zones of the car to absorb the energy; seat (and me) hopefully will remain attached to the tub/cage/car.

hopefully, i will not have anything further to report with respect to these types of experiences in the near future!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Greyout &raquo;</TD></TR><TR><TD CLASS="quote">if aluminum seats aren't FIA-approved, then how are the legal for racing?</TD></TR></TABLE>
FIA != SCCA

 

ok, time to ask...

wtf does != mean

 

Not equal to...

 

While I have commented on the use of seatbraces as they pertain to the rules, I am not in favor of them where FIA seats are concerned.

As has been pointed out in this thread, the composite seats are designed to flex. The flex absorbs some of the energy of the impact much like crumple zones in a street car. Maybe a better example would be climbing rope. It is designed with a certain amount of elongation or stretch to absorb the impact of a fall. The problem with only mounting the seat by the sidemounts is not in the seat. It is in the floorpan. Yes, I said floorpan. How much you want to bet that somebody would try to mount to the stock unreinforced floorpan?

IMHO, the Al seats, with the exception of those with shoulder supports, are there to hurt you. Most of them support the upper torso by the ribcage. The shoulder girdle is where the support should be. If you wanted to push someone over sideways, would you push them by the shoulder or the ribs mid-torso? Try it with the subject resisting. See the movement @ the shoulder level. Now image a seat that trys to limit lateral movement @ the ribs with the addition of the bolt on head supports.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by elgorey &raquo;</TD></TR><TR><TD CLASS="quote">
FIA != SCCA </TD></TR></TABLE>

elgorey == computer geek

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Greyout &raquo;</TD></TR><TR><TD CLASS="quote">
ok, time to ask...
wtf does != mean</TD></TR></TABLE>

Greyout != computer geek