71 replies to this topic

[Keith Novak]

Are there challenges attaching a back brace to a carbon fiber seat?

I don't think it's a good idea unless the seat was designed for it but others may disagree. It has the potential to greatly weaken the seat at the bolting area but that depends a lot on the seat construction and the drilling. The curvature of the seat can make it more challenging to attach a brace with a good contact area. If you decide to do it, be very careful when you drill and wear a mask and goggles at a minimum. Carbon fiber is hazardous material. The fibers are like little tiny sharp porcupine quills that are really good at penetrating soft tissue like your eyeballs or the inside of your lungs and then stay there.

[Danny Steyn]

Are there challenges attaching a back brace to a carbon fiber seat?

If the seat already has an integrated mount, no problem. If not see above, and I suspect mounting a carbon fiber seat without an integrated mount would probably void any FIA/SFI or other certification

[Danny Steyn]

Danny- Great post. When the floor buckled, what happened at the rear mounting points? My thought would be that in a backwards crash the front would pull up and the rear would push down making the reinforcements at the front the most important. Curious as to if that's what you saw or both pulled up.

Keith, both front and rear pulled up. The entire floor was pulled up around the mounting bolts well above the original position, and there were serious fatigue cracks in the floor emanating from the seat mounting bolt holes .

[Danny Steyn]

Never worry about blaming Kyle for things even when its not his fault, i do.

Danny let me follow up on one point that supports your opinions. From my limited bio-mechanical background, our anatomy is designed to handle a frontal impact much more so than a lateral impacts. The rib cage will support your internal organs on a frontal impact and hold your heart in place. On a side impact there is not as much support for the heart and other organs, or said another way, there is more room in your chest for your organs to move sideways compared to forwards and back.

So in a side impact it takes much less force to cause a more serious injury, such as a Torn aortic artery. A fatal injury 100% of the time.

I agree with you that you cannot oversell Safety.

So how hard is it to get in and out of that seat with the shoulder containment?

Frank - thanks for the medical advice - makes sense. As to entering and exciting, it takes more of a bend, but it is easy for me to do now. Going from the older seat to this one you immediately notice the shoulder bolsters in the way, but after a few sessions it feels totally normal getting in and out. In terms of driving you feel way more connected to the car as it contains you more, but you do have to learn to shift with less elbow movement!

[Keith Novak]

Keith, both front and rear pulled up. The entire floor was pulled up around the mounting bolts well above the original position, and there were serious fatigue cracks in the floor emanating from the seat mounting bolt holes .

Wow! Thanks. That meant your body had to move up relative to the car with enough energy that not only did you crack the roof with your head but the belts pulled up hard enough on the seat's belt holes to do that to the floor. Glad you didn't break your neck. It makes sense. The rear impact is likely to pitch the car nose up. I hadn't thought about that before but I sure will now.

[ChrisA]

...but the belts pulled up hard enough on the seat's belt holes to do that to the floor. .

I took it to mean that the seat essentially pivoted backwards on impact causing the front mount point to pull up the floor pan. Hope that was a correct read Danny..?

[ChrisA]

So how hard is it to get in and out of that seat with the shoulder containment?

Frank, I just install the same seat in my car last fall. It is a bit more of a squeeze getting in and out for me, but that is partly because I'm short, placing the seat a little closer to the A-piller. I haven't tried getting out with the door shut yet. Not sure I could pull it off with that vent window piller in place. I'll have to look into a solution for that when it warms a little. I do really like the full containment aspect of the seat, especially when you look at how closely we are positioned to the side of our cars.

[Keith Novak]

I took it to mean that the seat essentially pivoted backwards on impact causing the front mount point to pull up the floor pan. Hope that was a correct read Danny..?

If the seat just pivoted backwards, the front mounts would be pulled but the rear would act as the fulcrum and either be twisted or pushed down. That's what I was envisioning before. Pulling up on the rear mounts also would seem to indicate the lap belt and/or the shoulder belts were also pulled up hard enough to try and lift the whole seat. I don't see anything else that could pull the whole seat up other than your body pulling hard enough on the belts to lift the back of the seat along with you.

Makes sense when I think about the dynamics of a crash. A typical seat has a 20* layback angle. Hitting hard from the rear, the back of the car is likely to dive and the front raise up so now your body is tipped back further. That puts a big chunk of the forces up into the belts instead of into the seat back. That's what I hadn't thought of. I generally thought about a rearward crash being back into the seat instead of so much up into the belts making the front mounts much more critical than the rears.

[David S.]

Thanks for all of the responses. I ordered a set of the Good-Win Racing mounts this morning. I will be sure to take pics of everything and post it in here when I install them. Just for future reference for anybody that comes across this thread while looking for answers please post pics of your seat mounts if you have any.

[Keith Andrews]

Frank, I just install the same seat in my car last fall. It is a bit more of a squeeze getting in and out for me, but that is partly because I'm short, placing the seat a little closer to the A-piller. I haven't tried getting out with the door shut yet. Not sure I could pull it off with that vent window piller in place. I'll have to look into a solution for that when it warms a little. I do really like the full containment aspect of the seat, especially when you look at how closely we are positioned to the side of our cars.

This rule allows for the removal of the drivers side A-pillar. It just makes it a little easier getting out and I was able to get out the window after a heavy impact that made it difficult to open the door.


To improve driver exit through the window area, the driver vent window and vent window supporting frame may be removed as an assembly. If removed, ducting may be in the passenger side vent window only.

[wheel]

Russ said, "Also (if I understand correctly), A FIA seat, if solidly mounted (not on sliders), does not require a back brace, but only during the the window of time the FIA sticker is valid (5 years?). In other words, a FIA seat may not need a back brace initially, but will after a few years."

A FiA seat, properly mounted will never require a back brace. The rule says, Seats that have been homologated to and mounted in accordance with FIA standard 8855-1999, or seats that have been certified to FIA. Standard.8862-2009 or higher need not have the seat back attached to the roll structure

Like fuel cells, window nets, etc. the the seat does not "time out"

[Keith Novak]

The rule says, Seats that have been homologated to and mounted in accordance with FIA standard 8855-1999, or seats that have been certified to FIA. Standard.8862-2009 or higher need not have the seat back attached to the roll structure

Like fuel cells, window nets, etc. the the seat does not "time out"

The certification times out just like belts and helmets and for the same reason. Saying it's ok because it was certified in the past even though now it's not is like saying it's OK because it was mounted properly at one point but now it's sitting loose on the floor.

[wheel]

Keith,
The rule was re-written and is pretty plain. If they have been homologated, they do not need the back attached to the roll cage.
wheel

Seats that have been homologated to and mounted in accordance with FIA standard 8855-1999, or seats that have been certified to FIA. Standard.8862-2009 or higher need not have the seat back attached to the roll structure

[Keith Novak]

If it's meant to read like you're interpreting it, it's a very poor safety rule. If it's not, it's poorly written. Without going all grammar Nazi, I read it differently. I'll be submitting a letter on that one to at least get a definitive ruling.

[wheel]

Keith,
The CRB discussed this extensively. You may read it any way you choose, but the intent is that you do not need to time out your seat. Many of the FIA seats are not designed for back braces and adding them could possibly compromise the safety of the seat. We did not want to get into mandating something that might not be safe. So, if you have a seat that was homologated and mounted to the stated standards, you are good as long as you choose to keep the seat.
Of course, if you want to time out your seat, or put on a back brace, that is up to you. You just are not required to do so.
wheel

[Keith Novak]

If that's what the CRB intended then it is what it is and still poorly worded.

I suppose that makes it all the more important to emphasize that over time the materials of the seat can lose a lot of their strength and what the FIA cert once meant is completely out the window. The materials in the seat may have lost a lot of their strength and the seat may not behave as designed and tested. On the other hand, a back brace can make the seat more rigid but in places that the seat wasn't designed for either and dangerous in a different way. It's a lose lose situation.

I don't mean to be a PITA about this. I look at it the same way as helmets and I've busted a few of those instead of my skull so I have a great deal of respect for my safety gar. In either case, better performance will usually cost you more but that performance will only last for so long. If you justified the additional cost due to the improved performance, once you're using it beyond the expiration date due to the cost, you're now dealing with questionable performance.

[wheel]

And I don't mean to be defensive, but the rule is not poorly worded. Like everything else in racing, you take responsibility for your own safety. The rules can only give you guidelines. Personally, I started racing in an MGB with a simple single-hoop roll bar which was braced with tubes held in with bathtub caulk. (the welder ran out of gas late at night before we could finish the braces). But, I also started using a Hans well before they were mandated. That is the difference between 26 and immortal and 66 and smart. I have an FIA seat in the Miata with a back brace designed by an engineer so that it braces the seat but does not compromise the seat construction. The rule, however, was written with the help of lawyers, which is why an engineer might consider it poorly worded. ;-)

wheel

[David S.]

Well, I just sold my Sparco's because they were set to expire in Jan. 2014 and I didn't want to build a cage around a temporary seat. I'm glad I didn't know about this rule until now otherwise I may have contemplated keeping the outdated seats.

[john mueller]

Seat braces are fine, just NEVER drill a composite seat.

[Keith Novak]

Seat braces are fine, just NEVER drill a composite seat.

I don't agree with either part of that. A composite seat can be designed to act like somewhat a trampoline and catch you as opposed to just stop you. A back brace can be like putting a saw horse under the trampoline. The flexy parts will catch you but that saw horse location will stop you cold at the area of impact and force the rest of you to bend around it in way that was never intended. You can also drill composites safely. It's done all the time but to do it safely there is a lot of consideration required into where you can drill, how you can drill, and how to reinforce area around the hole. If I were to design a brace for a composite seat, I'd either add a lot of reinforcement to the back brace area to spread the load in the seat and your body, or I'd brace the seat from the sides to allow the back to flex like a trampoline without a saw horse under it.