Seat Back Brace Question

[dickita15]

While I am not a fan of the ban on sliders without a brace and think in time we may find a better compromise there was a reason for the rule change.
For those that have to deal with the change I will remind you there is a huge amount of freedom in how a seat back brace is designed.
I could build and install a legal brace in an hour with a hammer, vise and a piece of flat stock that would not be a spear. If it needed to be adjustable it might take an hour and a half.

[Chip42]

While I am not a fan of the ban on sliders without a brace and think in time we may find a better compromise there was a reason for the rule change.
For those that have to deal with the change I will remind you there is a huge amount of freedom in how a seat back brace is designed.
I could build and install a legal brace in an hour with a hammer, vise and a piece of flat stock that would not be a spear. If it needed to be adjustable it might take an hour and a half.

the chnage may be defensible in an otherwise logical rule.

fix the mounting rules, then see if the change is waranted. cat's out of the bag, but I personally see no logic behind it. carry on.

[Greg Amy]

I could build and install a legal brace in an hour with a hammer, vise and a piece of flat stock that would not be a spear.

Yes, but would it also have the designed-in flexibility to absorb energy that all FIA seats have? Or would it convert a very good seat into nothing more "safe" than something made out of lumber, sheet metal, and covered in leftovers from Aunt Tilly's sofa (which is also SCCA-legal as long as it is "securely mounted" and has a seat back brace)...?

[Knestis]

I'm going to make my brace out of the same material used in some RX7 rear suspension arm bushings.

K

EDIT - And what Greg said. Again. And again. It's so frustrating trying to take a meaningful, nuanced position that's actually grounded in SAFETY rather than meeting a rule. The Club spends so much time on the latter that they lose sight of the real point.

[seckerich]

While I am not a fan of the ban on sliders without a brace and think in time we may find a better compromise there was a reason for the rule change.
For those that have to deal with the change I will remind you there is a huge amount of freedom in how a seat back brace is designed.
I could build and install a legal brace in an hour with a hammer, vise and a piece of flat stock that would not be a spear. If it needed to be adjustable it might take an hour and a half.

And all because one person was too stupid to mount their seat securely and it came loose. As said before, stupid fix that is not grounded in reality. When you make a rule that you then suggest we "work around" that is less safe than the original rule we have all raced with for years you have failed at your job. Also reminds me of the same advice for motor mounts to use a chain.

[Chip42]

Also reminds me of the same advice for motor mounts to use a chain.

but that wont end up killing or paralyzing someone.

[dhardison]

So I have a Momo Start composite seat that is quite possibly past the 5-year mark (need to dbl-chk). If/when I install a 'spear', do I need to bolt it to the seat?

I know the GCR states that the brace must be "firmly attached", so I'm pretty sure the answer is yes, but "firmly attached" could be done with Gorilla glue, duct tape, etc. (I semi-kid). However I've read where Momo explicitly states NOT to drill holes in their seats, expired or not.........

Dan

[Chip42]

So I have a Momo Start composite seat that is quite possibly past the 5-year mark (need to dbl-chk). If/when I install a 'spear', do I need to bolt it to the seat?

I know the GCR states that the brace must be "firmly attached", so I'm pretty sure the answer is yes, but "firmly attached" could be done with Gorilla glue, duct tape, etc. (I semi-kid). However I've read where Momo explicitly states NOT to drill holes in their seats, expired or not.........

Dan

a new one is cheap. not as cheap as a brace, maybe, but much cheaper than whatever will happen to you if you drill holes in the shell.
http://ltbautosports.com/most20rasebl.html

[dickita15]

So I have a Momo Start composite seat that is quite possibly past the 5-year mark (need to dbl-chk). If/when I install a 'spear', do I need to bolt it to the seat?

I know the GCR states that the brace must be "firmly attached", so I'm pretty sure the answer is yes, but "firmly attached" could be done with Gorilla glue, duct tape, etc. (I semi-kid). However I've read where Momo explicitly states NOT to drill holes in their seats, expired or not.........

Dan

i would never drill holes in a composite seat. if you need a slider i would be thinking adhesive for the back brace but that is just me.

[Knestis]

The importance of what Dick is saying has been lost among the other issues. Read it again, everyone.

K

[Chip42]

i would never drill holes in a composite seat. if you need a slider i would be thinking adhesive for the back brace but that is just me.

a LOT of people have no idea how important this is. Wording to this end, along with guidlines and $&*^!!*# mounting rules (seriously) should be IN GCR 9.3.4.1

[Greg Amy]

i would never drill holes in a composite seat. if you need a slider i would be thinking adhesive for the back brace but that is just me.

I agree: drill no holes in a composite seat. But then again, (almost?) all FIA-approved seats are composite, so the SCCA is not only encouraging, but in some cases mandating, such modifications to composite seats.

RaceTech provides inserts for their seats that are 'glassed in, because SCCA Pro mandates seat back braces.

http://www.racetechseatsna.com/produ...TINSERTKIT.php

[dickita15]

There is nothing in the wording “firmly attached” that requires drilling holes.
I am just saying a length of flat stock, some double stick tape and a couple of muffler clamps to attach to the cage and I would sleep well.

[Chip42]

dick,

I think the people still following this all have the following in common:

*We believe in safety, not rules for their own sake with no demonstrable, positive effect on safety

*We understand the structural characteristics of fiber composites and the other designs common in racing seats, FIA and otherwise

*We understand ways to mitigate the problems of interaction between the particular seat and the back brace rule.

BUT there are a ton of racers who simply don't know this stuff. and the rules say they need to have a back brace on their FIA seat, say a momo start as came up earleir (GFRP). They see an add in sportscar for a back brace from IO Port and buy it, drill 2 holes, add some bolts, and go to the track. What they have done is unsafe, as we all know. but it is legal, meets a REQUIREMENT, and there is NOTHING in the rule to disuade them from this solution, nor guidance toward a safe construction, therefore there is nothing the tech can do other than recomend an alternative, but he's not able to rule it as illegal unless you give him a good rule.

had they a Sparco Sprint 5 or similar, they'd be bolting through nylon webbing. or maybe they'd realize that the brace and the seat aren't compatible, and get frustrated, miss their weekend, who knows. maybe they wind up in a economy kirky or a blow-molded Jaz. is that what we're trying to get them into? really?

meanwhile, those with and without sliders can continue to pop rivet their seat to rusted sheat metal using 3/8 washers because the existing rules are inadequate in that regard. yes, this is a stretch, but no, it is not illegal as written.

[dickita15]

Chip, I fully understand your frustration. I hope you remember I said I do not like the rule and was hopeful for a better solution. That a way can be found to allow a slider that is high enough quality to work.
The problem that spurred this rule is real. When someone buys a $1500 seat and then bolts it on top of a factory slider it causes a problem. When you can reach in and grab the top of a seat and it moves so much that it hits the cage it is a problem. So someone wrote a rule to address it.
Chip, I understand your frustration with rules that allow people to do poor mountings but I really do not want to go down the road where the rules are so narrowly written that you have no flexibility to install what is best for my own car.

[Russ Myers]

Don't keep the back brace straight. from an old book by Benny Parsons, put two bends in the back brace, z'ing the "spear". This allows it to remain rigid when holding your seat, and allows some give when chrashing.

Russ

[joeg]

Most composite seats I know of actually have holes drilled in them--in the side where the manufacturer installs nutserts for the side mounts.

I would not hesitate to drill and use nutserts for the back brace--if that defines "firm attachment". The problem is the brace.

[Chip42]

Most composite seats I know of actually have holes drilled in them--in the side where the manufacturer installs nutserts for the side mounts.

I would not hesitate to drill and use nutserts for the back brace--if that defines "firm attachment". The problem is the brace.

This is not true. FIA seat "nutserts" are embedded plates within the construction, the standard specifies they have a minimum area of 200mm^2, with the threaded hole centered within an enclosed circle of 40mm diameter (i.e. 20mm from the hole center to any edge of the plate). a nutsert will spin in a drilled hole in fiberglass with very little torque, and the hole interupts the fiber and introduces stresses to the resin, causing a reduction in overal strength and a yield point, as well as the liklihood of cracks propogatiing throughout the shell under vibration, so the seat is even more weakened just by using it, and before it is called upon to contain you in a wreck.

good explanation of how this works in Colin Chapman, Lotus Engineering by Hugh Haskell

the problem is both the stuctural integrity being compromised by those who are attempting to conform to a rule and don't understand the materials (thank you for proving my point) AND the danger posed by the "spear" should such a design (the common, off the shelf, advertised "easy button") be used.

[Chip42]

Chip, I fully understand your frustration. I hope you remember I said I do not like the rule and was hopeful for a better solution. That a way can be found to allow a slider that is high enough quality to work.
The problem that spurred this rule is real. When someone buys a $1500 seat and then bolts it on top of a factory slider it causes a problem. When you can reach in and grab the top of a seat and it moves so much that it hits the cage it is a problem. So someone wrote a rule to address it.
Chip, I understand your frustration with rules that allow people to do poor mountings but I really do not want to go down the road where the rules are so narrowly written that you have no flexibility to install what is best for my own car.

Dick, I'm not arguing with your position. but what I've been saying to you, this forum, the CRB in letters, etc... is that the failure(s)we've seen are the result of poor mounting rules. specify harware grades, minimum area of a washer for use when bolting to sheetmetal, forbid the use of factory sliders (THAT was a good rule), and make a statement about seat flex vs drivers head or the seat hitting cage elements (don't let it, pad with something like SFI 45.1/2 at minimum). how is that narrow? How does that change your ability to determine the appropriate seat installation for your car? The rule change that you suggest "addresses" the problem does, in fact, nothing to affect a change to it, it simply adds more stuff without guidlines or minima.

I agree that a back brace CAN be made to be safe, but I'm stating that it is NOT needed and ADDS confusion, complexity, and the chance for seat failure and driver injury, while addressing the ACTUAL problem (no mimimum guidlines for mounting) would have been a better FIRST action. Further, the fact that the rule does not make recomendations to help avoid unsafe instalations makes it worse than doing nothing. the other fact is that there is no one brace design that fits all seats and that can be proven safe without sled testing.

Will someone PLEASE explain to me how a back brace (without any spcifications other than "attached") is going to keep a poorly mounted seat from being dangerous? Especially when someone who mounts their seat poorly is apt to design and install their back brace with equal attention to detail?

CRB/BOD fail.

[Chip42]

fwiw, this is the lette rI sent to the CRB in AUGUST 2010.

Proposed rule, August 2010 Fastrack:

In 9.3.41, first paragraph, replace “Seat supports shall be of the type listed on FIA technical list No.12 (lateral, bottom,
etc).” with “Seat supports shall be of the type listed on FIA technical list No. 12 or No. 40 (lateral, lower, floor, back, etc) .In accordance with the FIA standards, the seat supports (brackets) must be those used when the seat was tested for homologation. Unless supporting evidence is provided by the manufacturer of a series produced car that shows FIA safety cage testing for homologation included an adjustable seat mount, seats and their supports must be attached to a fixed mounting structure.”

I recommend changing the language above to reflect that seats conforming to FIA standard 8855-1999, as listed in technical listing No. 12, are homologated with only the ”type” of bracket intended (8855-1999, 1.2) and NOT a specific seat mount part number. Technical list No. 40 specifies part numbers for the mount(s) used as they are homologated with the seat. Per 8862-2009, section 4.8 Seat-Brackets: “The seat brackets shall be considered part of the seat and shall share the seat homologation number.” This is a distinction that I think should be noted in the GCR as it has been misunderstood by many. It should be noted that the mounting of an 8855-1999 seat is subject to some level of official approval of fitness – I suggest this be by the scrutineer performing the annual inspection. It is odd to me that both the current and proposed rules are so devoid of specifics concerning the seat mounting. As a set of minimum criteria is needed in order to make a consistent determination in this regard, I propose a minimum of 3mm thick steel or 5mm thick aluminum should be used for mount brackets that are not identifiable as being from the manufacturer of the seat (be they generic, custom, or unmarked). These material dimensions are based on a sampling of the available offerings from several FIA-approved seat manufacturers. Seat mounts should be attached to the structure of the vehicle in such a way as to prevent movement in a collision; I recommend that it be in accordance with the driver’s restraint rules in 9.3.19.F. I also suggest the addition of ISO grade 8.8 as an alternate minimum fastener due to the common practice of using metric threads in FIA seat mounting bosses.

I believe that any rule requiring the addition of a back brace to a safely mounted seat is not well founded, even if well intended. FIA seats are typically NOT built to accommodate the installation of a back brace, and leaving the design of such a device to the competitor could result in required mounting that compromises the integrity of the seat back structure and could potentially cause serious, unintended harm to the driver. I have spoken to resellers and factory representatives from Cobra, Momo, Sparco, and OMP who all state that the addition of a seat-back brace to an FIA seat, particularly a composite shell seat, is dangerous and not recommended. Many of them offered stories of seats with back braces bolted to them that had cracked or been otherwise severely compromised in a wreck. Requiring replacement seat in order to properly accommodate a seat back brace could be crippling to a racer’s budget, particularly as many are still preparing to purchase required head and neck restraints, updated belts, etc…

Additionally, adjustable mounts for use in endurance cars can be a defacto requirement. Given the variety of cars that often cannot fit a back brace to allow both short and tall drivers (del sol, MR2, X1/9, etc…), and the potential for injury should the installed device compromise the seat back, there needs to be some language or provision for the use of adjustable mounts that conform to some acceptable standards that will allow the use of an 8855-1999 homologated seat without a back brace. These mounts need not (and in most cases, should not) be those supplied with the vehicle, but could be the type sold by the manufacturer of the seat or custom fabricated for the purpose and subject to some approval either at the scrutineering level or through a compliance review such as GCR 8.1.4. As it is very important to a large portion of the active community that there be a way to approve well designed mounting that permits quick repositioning of the seat, said rule must not rely solely on the seat or car manufacturer to offer an FIA approved adjustable mount, particularly as there is no applicable FIA standard for seat mounting brackets outside of 8862-2009 where they are co-homologated with the seat – meaning only certain exotic GT’s might meet the criteria as proposed.

As such, I recommend the following language in place of that proposed:

Seats homologated to FIA standard 8855-1999 are listed on FIA technical list No. 12 along with the type of support used in homologation, i.e. lateral or lower. In accordance with the FIA standards, the seat supports (brackets) must be the type used when the seat was tested for homologation. Where seat mounting brackets are not, or cannot be identified as being of the same manufacturer as the seat, a minimum material thickness of 3mm steel and 5mm aluminum alloy shall be used. Lower mount seats may be mounted directly to the floor of a production based vehicle, provided the attachment meets the minimum criteria outlined herein. Scrutineering shall be responsible for making a determination of the fitness of a seat mount and its installation.

Seats homologated to FIA 8862-2009 shall use the brackets homologated with the seat as listed in FIA technical list No. 40.

Seat brackets may be welded or bolted to the frame or roll structure of the car, bolted to the factory seat mounting bosses, or to steel floor boards of production based cars using 2” minimum diameter washers or equivalent. All bolts used should be SAE grade 5 or ISO 8.8 minimum, hardware without grade markings is unacceptable. Holes in the roll cage to facilitate bolting shall be bushed and welded completely.

Unless supporting evidence is provided by the manufacturer that shows FIA safety cage testing for homologation included an adjustable seat mount, seats and their supports must be attached to a fixed mounting structure. Exceptions may be approved on a case by case basis by a National or Senior Scrutineer or through the Compliance Review process (see 8.1.4). Mass produced items may be approved by the CRB and listed in the GCR.

The competitor is required to have a copy of the relevant FIA technical list and any additional homologation certificates or other certifying documentation on hand at all events.