30 replies to this topic

[wera44]

Before anyone says anything I know my welds look like crap. Will this seat back brace I made pass tech? I could also weld two pieces either side of the main plate to cup the seat.

Attached Files

•  IMG_8823.JPG   45.39KB   8 downloads
•  IMG_8822.JPG   77.43KB   4 downloads

[wheel]

Seat back braces are not required. The driver’s seat shall be a one-piece bucket-type seat and shall be securely mounted, so as to provide fore/aft and lateral support. 

[wera44]

Sorry, should have been more specific. NASA tech does require it on any non FIA seats and out of date FIA seats. Doesn't need to be directly bolted but it must be there to brace it. Kirkey suggest that seat back brace is bolted so I'm on the fence on that as well but for safety sake will probably bolt it in.

[davew]

Just having the brace does not add any side to side security. the brace needs to be attached to the seat. Make your plate larger and add a nut/bolt or two

[Ron Alan]

. Doesn't need to be directly bolted but it must be there to brace it. 

Maybe the rule has changed or I'm confusing my organizations...but I seem to remember a big discussion about bolting to composite seats? Which directional loads is the seat brace intended for? Asking this to anyone in the know for future reference...

[Steve Scheifler]

What Dave said. The upper part of that Kirkey twists and flexes more than you might think. I made braces using old sway bar links/heims for simple adjustment but they allow more flex than I like unless tensioned a lot. With our seats nearly touching the rear wall there is nowhere for them to go anyway so torsional strength is the main benefit.

[wera44]

Thanks for the advice Dave. I'll weld in two more pieces on the sides to cradle the curve of the seat and add bolts.

[Bench Racer]

Seat back braces are not required. The driver’s seat shall be a one-piece bucket-type seat and shall be securely mounted, so as to provide fore/aft and lateral support. 

No disrespect to Wheel, BUT,  securely (I understand it's a GCR word), is a very subjective word and different tech's will have different definitions of what securely means. Bolts plate to seat and you'll have zero issues.

 

Agree with Dave to increase the plate size. If you chose to make your attaching tube cleaner, you could go smaller in diameter and have a single tube bent as required. Or a single straight smaller tube attached at an angle from your cage cross tube to the larger seat plate. 

[wheel]

I just quoted the SCCA rule.  There were many discussions, over a long period, about FIA seats, sliders, back braces, yada yada yada.  The CRB just decided to go back to the old rule.  Mount it securely.  If a tech inspector can grab the back of the seat and wobble it around, they won't pass it.  My car has a back brace with a very large plate to distribute the load.  It does not move 1 mm.  If you are going to be the one sitting in the seat, consider what will happen to the seat in any type of impact, and mount it accordingly.

[Ron Alan]

^^^But aren't the composite seats "designed" to flex? My NEW seat flexes side to side but is fastened securely(subjective per Dave) to its floor mounts! 

[wheel]

Well, if you are going to complain about it, we can always change the rule back and require a back brace and you can figure out a way to mount one on an FIA seat that was not designed for one.  I have not heard one single issue where a seat, FIA or otherwise, has been bounced because of a little flex.  If this is really a problem we can always go back to a restrictive rule.  

[Johnny D]

I did my composite Ron and bolted it. I like it, it was flexing too much.

I think Craig mentioned to me though I didn't have to.

Personal preference.

 

I/O got 3 kinds now

http://www.ioportrac...djust-i/o-port/

http://www.ioportrac...omposite-seats/

http://www.ioportrac...e-kit-i/o-port/

 

J~

[wheel]

This is another case where folks complain about the complex, long-winded rules.  So, instead of writing two paragraphs, defining tubing sizes, bracket angles, plate sizes, ad nauseam, we write a simple sentence, and get called on it.  I'll stay with what we have.

[Johnny D]

Just to be clear my comment was NASA related. Maybe Xav can confirm.

J~

[wheel]

JD, clear.  I was responding to Ron.  That's why personal conversations are better than web posts.  

[Bench Racer]

I'm not going to look and post another time a seat manufactures info. One of the big time composite seat manufactures is implementing a composite square tube into the rear of their seat to accommodate bolting to support brace/roll cage. Same company has a kit to mount composite seats to support brace/roll/cage.

[wheel]

There are a number of FIA seats with built in mounting points for back braces.  I would probably go with one of those, if I was building a new car.  Pretty pricey, but......

[Ron Alan]

JD, clear.  I was responding to Ron.  That's why personal conversations are better than web posts.  

My post was tongue in check...I like the SCCA rule clarification! I wish NASA  would adopt! But in the meantime in all seriousness I do want to know if the back brace per the NASA rules does not have to be connected to the seat as was posted by others...

[wheel]

don't know nuthin bout no nasa.

[wera44]

15.6.21 Seat Back Support

A seatback support must be made to hold the seatback from failing in the event of a crash. A plate shall be used to distribute the load. No bolts, corners, or sharp objects should be placed in such a manner that could lead to a possible puncture of the driver in a high impact crash. Seat back support need not be attached to the seat itself. Proper design and installation is crucial to safety and it is recommended that the driver employ the services of a professional race car builder for this, as well as all other vehicle safety items. An exception may be made for those seats homologated to, and mounted in accordance with, FIA 8855-1999 or 8862-2009 standards. Those seats that qualify for the aforementioned exception must conform to the entire FIA 8855-1999 or 8862-2009 set of regulations, as applicable. This includes a mandatory seat replacement, or use of a seat back brace, for any seat more than five (5) years old (8855-1999) or more than ten (10) years old (8862-2009). Please reference the FIA regulations