Seat Back Brace Question

Simon T.

Simon T.

New member
I'm making my own seat back brace, does the brace need to attach to the seat or just rest against it? I glanced through the GCR and couldn't find it.
 
9.3.41. SEATS
The driver’s seat shall be a one-piece bucket-type seat and shall be securely mounted. The back of the seat shall be firmly attached to the main roll hoop, or its cross bracing, so as to provide aft and lateral sup- port. Seats homologated to and mounted in accordance with FIA stan- dard 8855-1999, or FIA.Standard.8862-2009 or higher need not have the seat back attached to the roll structure. Seats with a back not at- tached to the main roll hoop or its cross bracing may not be mounted to the stock runners unless they are the FIA homologated seats specified in an FIA homologated race car. The homologation labels must be visible. Seat supports shall be of the type listed on FIA technical list No.12 or No. 40 (lateral, bottom, etc). Passenger seat back–if a folding seat, it shall be securely bolted or strapped in place.
Mounting structures for racing seats may attach to the floor, cage and or center tunnel. Seat mounting points forward of the main hoop, between the center line of the car and the driver’s side door bar and rearward of the front edge of the seat bottom are not considered cage attachment points in classes with limitations on the number of attach- ments.
A system of head rest to prevent whiplash and rebound, and also to pre- vent the driver’s head from striking the underside of the main hoop shall be installed on all vehicles. Racing seats with integral headrests satisfy this requirement.
The head rest on non-integral seats shall have a minimum area of 36 square inches and be padded with a minimum of one inch thick padding. It is strongly recommended that padding meet SFI spec 45.2 or FIA Sports Car Head Rest Material. The head rest shall be capable of with- standing a force of two-hundred (200) lbs. in a rearward direction. The head rest support shall be such that it continues rearward or upward from the top edge in a way that the driver’s helmet can not hook over the pad.
 
I believe these are way under valued, I have always had one on every seat I drive. I believe the real benefit will be in a side impact to keep the seat straight. Also be careful not to mount to low where your heavier upper body could fold the seat around it in rear impact causing back damage. The first car I bought had welded in "home made" very low. I believe in a real hard rear impact, the aluminum seat would have folded around this thing and snapped me in two.
 
It's only a matter of time before one of these seat back braces is directly responsible for someone being crippled or killed.

FIA seats - you know, ones that are designed specifically for the purpose and tested to destruction? - don't use seat back braces. And there's a reason for that.

And we're worried about head and neck braces... <rolleyes>
 
Greg, as a tech inspector, let me ask you a few questions. Not looking for a formal opinon of course, just want to bounce some ideas off of you.

Seat in my car is an FIA seat (Sparco) with a bottom mount ONLY.

Been looking for another seat and settled on the Sparco PRO 2000, which is also FIA homologated and also bottom mount.

Now, as I read the above rule, the seat must meat the standard and be mounted the same way as set forth in the standard.

I've read the standards and they are not entirely clear on this. They seem to suggest only testing with seat brackets (which I don't want to use) but I don't believe that Sparco could have gotten the FIA sticker for the seat if the bottom mounts hadn't be tested as well.

Thoughts?

By the way, I fully agree with you on those spears in the back of seats. Composite seats aren't designed for that.

Simon, what I've read on FIA v. non-FIA is that FIA won't give approval to an alum seat like a Kirkey. The FIA thinking is that an aluminum seat is not as safe for a variety of reasons.

US thinking seems to be different; Nascar boys have been using versions of that seat, with many improvements, for years.

I've raced cars with Kirkeys and things feel fine, but after reading the standards and the testing required to get an FIA cert I would not feel comfortable owning a seat that was not so tested.

The idea that a back brace is a sufficient replacmeent for that esting is a bit spooky to me.

QUOTE=Greg Amy;317623]It's only a matter of time before one of these seat back braces is directly responsible for someone being crippled or killed.

FIA seats - you know, ones that are designed specifically for the purpose and tested to destruction? - don't use seat back braces. And there's a reason for that.

And we're worried about head and neck braces... <rolleyes>[/QUOTE]
 
I beileve there was a SFR SM racer who broke some ribs on a seat back brace that was part of the cage that rested aginst the seat back. This would have been about 7-8 years ago.
 
JeffYoung said:
Greg, as a tech inspector, let me ask you a few questions. Not looking for a formal opinon of course, just want to bounce some ideas off of you.

Seat in my car is an FIA seat (Sparco) with a bottom mount ONLY.

Been looking for another seat and settled on the Sparco PRO 2000, which is also FIA homologated and also bottom mount.

Now, as I read the above rule, the seat must meat the standard and be mounted the same way as set forth in the standard.

I've read the standards and they are not entirely clear on this. They seem to suggest only testing with seat brackets (which I don't want to use) but I don't believe that Sparco could have gotten the FIA sticker for the seat if the bottom mounts hadn't be tested as well.

Thoughts?

By the way, I fully agree with you on those spears in the back of seats. Composite seats aren't designed for that.

Simon, what I've read on FIA v. non-FIA is that FIA won't give approval to an alum seat like a Kirkey. The FIA thinking is that an aluminum seat is not as safe for a variety of reasons.

US thinking seems to be different; Nascar boys have been using versions of that seat, with many improvements, for years.

I've raced cars with Kirkeys and things feel fine, but after reading the standards and the testing required to get an FIA cert I would not feel comfortable owning a seat that was not so tested.

The idea that a back brace is a sufficient replacmeent for that esting is a bit spooky to me.
Click to expand...

Well my seat isn't an aluminum it's either plastic or fiberglass it's a Sparco, not sure what model, but it's not FIA approved. At least there isn't an FIA patch on it.
 
Greg Amy said:
It's only a matter of time before one of these seat back braces is directly responsible for someone being crippled or killed.

FIA seats - you know, ones that are designed specifically for the purpose and tested to destruction? - don't use seat back braces. And there's a reason for that.

And we're worried about head and neck braces... <rolleyes>
Click to expand...

I would never get into a car with one of those spears pointed at my back - that just scares the hell out of me. But I believe it is possible to design a brace that won't hurt you, and still accomplishes the purpose. The one in my car is made from a piece of 1-1/4" flat steel, bent into sort of a U shape (actually more like 5 sides of an octagon), with the ends mounted to tabs on the cross bar that are about the seat-width apart. I haven't tested it (don't really plan to), but the idea is that the brace will deform enough in an impact that it will both prevent injury (by allowing some movement) and help dissipate some of the energy of the impact. Needless to say it's a one-shot deal.
 
That's a damn good idea actually.

erlrich said:
I would never get into a car with one of those spears pointed at my back - that just scares the hell out of me. But I believe it is possible to design a brace that won't hurt you, and still accomplishes the purpose. The one in my car is made from a piece of 1-1/4" flat steel, bent into sort of a U shape (actually more like 5 sides of an octagon), with the ends mounted to tabs on the cross bar that are about the seat-width apart. I haven't tested it (don't really plan to), but the idea is that the brace will deform enough in an impact that it will both prevent injury (by allowing some movement) and help dissipate some of the energy of the impact. Needless to say it's a one-shot deal.
Click to expand...
 
What exactly are these spear braces you all speak of?

I plan on making mine sort of wrap around the back of the seat snug like to give the back of the seat good support, there is already a mount welded to the cage, I'm using tubing that goes through that, bolted in, then the end of the tube with the wrap around metal welded to that, also adjustable at the mount on the main hoop if it needs to be adjusted. I've seen some with just a bar pushing against the seat are those what you all speak of?
 
JeffYoung said:
...I don't believe that Sparco could have gotten the FIA sticker for the seat if the bottom mounts hadn't be tested as well.
Click to expand...
FIA publishes their list of approved seats, along with what type of mount with which they were certified. Here's the 8855-1999 list, for example:

http://argent.fia.com/web/fia-public.nsf/D7050711553B12ADC12575F60035B089/$FILE/L12_Approved_seats.pdf

If yours is on that list (and it should be) and it says both "lateral" and "lower", you can use either.

Simon T. said:
Most FIA seats cost a lot more than a non FIA seat.
Click to expand...
So does a lifetime of living in a wheelchair and blowing through a tube to move around.

Simon T. said:
What exactly are these spear braces you all speak of?
Click to expand...
It's not just the fact that many poorly-designed braces become spears upon impact, it's also due to the fact that any properly-designed seat has "give" - both laterally and longitudinally - to absorb a lot of the shock. If you get hit and the seat don't give, guess where all the shock is going to...? Yep: you.

Seat back braces are nothing but a very bad Band-Aid to accommodate poorly-designed seats that have illustrated a tendency to fail. In fact, they first came to the fore when we were still using factory seats in Showroom Stock cars, where the adjustable seat backs were breaking.

Use whatever seat you want - the "standards" required by SCCA are laughable - but don't think that a seat back brace is anywhere NEAR sufficient to give you a level of safety comparable to a proper race seat. In fact, I suggest it probably worsens the situation.

GA
 
Greg, THANK YOU. This is exactly what I was looking for.

The standard itself doesn't mention what type of testing was done to get the homologation. This does.

Much appreciated.
 
Greg Amy said:
FIA publishes their list of approved seats, along with what type of mount with which they were certified. Here's the 8855-1999 list, for example:

http://argent.fia.com/web/fia-public.nsf/D7050711553B12ADC12575F60035B089//L12_Approved_seats.pdf

If yours is on that list (and it should be) and it says both "lateral" and "lower", you can use either.


So does a lifetime of living in a wheelchair and blowing through a tube to move around.


It's not just the fact that many poorly-designed braces become spears upon impact, it's also due to the fact that any properly-designed seat has "give" - both laterally and longitudinally - to absorb a lot of the shock. If you get hit and the seat don't give, guess where all the shock is going to...? Yep: you.

Seat back braces are nothing but a very bad Band-Aid to accommodate poorly-designed seats that have illustrated a tendency to fail. In fact, they first came to the fore when we were still using factory seats in Showroom Stock cars, where the adjustable seat backs were breaking.

Use whatever seat you want - the "standards" required by SCCA are laughable - but don't think that a seat back brace is anywhere NEAR sufficient to give you a level of safety comparable to a proper race seat. In fact, I suggest it probably worsens the situation.

GA
Click to expand...

Well for the time being I don't have much of an option. :shrug: lol
 
Jeff, you're welcome.

Simon T. said:
Well for the time being I don't have much of an option. :shrug: lol
Click to expand...
Then keep in mind the "intention" for seat back braces is to keep you safe and in place in case the seat back breaks/permanently deforms. Design it to spread the load across the back of the seat as much as possible (i.e., a plate, and use panhead bolts towards your back, not hex heads) and try to let it have some "give" (no real suggestions for that). - GA
 
Greg Amy said:
Jeff, you're welcome.


Then keep in mind the "intention" for seat back braces is to keep you safe and in place in case the seat back breaks/permanently deforms. Design it to spread the load across the back of the seat as much as possible (i.e., a plate, and use panhead bolts towards your back, not hex heads) and try to let it have some "give" (no real suggestions for that). - GA
Click to expand...

Cool I'll keep that in mind and when I have some spare money upgrade to an FIA seat. Thanks.
 
And everyone owes a lot of gratitude to the CRB who DID NOT continue pushing STUPID and ILL CONCEIVED rules floated recently requiring a back brace on ANY seat, FIA or otherwise, unless it could be proven that the mounts used are the same PN as the mounts the seat was certified with, which is ONLY possible on seats conforming to FIA 8862-2009 (advanced racing seats) as listed on technical list #40. there's less than 20 of these. most FIA seats are homologated to 8855-1999, and listed on TL#12, specifying the TYPE of mounting used (lateral, lower) and nothing more.

in effect, it would have forced just about everyone to have back braces. if you think they are scary on a metal seat, try it on a composite, or worse, an entry level, steel-frame FIA seat with webbing through the back and seat floor.

a rare instane of safety rule restraint on behalf od the club. use FIA seats and avoid back braces for all of the good reasons above. even a well designed back brace is, to me, less desireable than a well designed and well mounted seat.
 
Chip42 said:
And everyone owes a lot of gratitude to the CRB who DID NOT continue pushing STUPID and ILL CONCEIVED rules floated recently requiring a back brace on ANY seat, FIA or otherwise, unless it could be proven that the mounts used are the same PN as the mounts the seat was certified with, which is ONLY possible on seats conforming to FIA 8862-2009 (advanced racing seats) as listed on technical list #40. there's less than 20 of these. most FIA seats are homologated to 8855-1999, and listed on TL#12, specifying the TYPE of mounting used (lateral, lower) and nothing more.

in effect, it would have forced just about everyone to have back braces. if you think they are scary on a metal seat, try it on a composite, or worse, an entry level, steel-frame FIA seat with webbing through the back and seat floor.

a rare instane of safety rule restraint on behalf od the club. use FIA seats and avoid back braces for all of the good reasons above. even a well designed back brace is, to me, less desireable than a well designed and well mounted seat.
Click to expand...


So does that mean that the seat mounting device is irrelvant on a 8855-1999 seat as long as the seat is mounted in the way it was tested (either laterally or lower)? And if that is the case, what is the issue with slider type rails then?

Because this whole seat mounting issue is starting to be a real pain in the ass.
 
You must log in or register to reply here.
Back
Top